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<pre><a name="line-1"></a><span class='hs-comment'>-- To make GHC stop warning about the Prelude</span>
<a name="line-2"></a><span class='hs-comment'>{-# OPTIONS_GHC -Wall -fwarn-tabs -fno-warn-unused-imports #-}</span>
<a name="line-3"></a><span class='hs-comment'>{-# LANGUAGE NoImplicitPrelude #-}</span>
<a name="line-4"></a>
<a name="line-5"></a><span class='hs-comment'>-- For list fusion on toListBy, and for applicative hiding</span>
<a name="line-6"></a><span class='hs-comment'>{-# LANGUAGE CPP #-}</span>
<a name="line-7"></a>
<a name="line-8"></a><span class='hs-comment'>----------------------------------------------------------------</span>
<a name="line-9"></a><span class='hs-comment'>-- ~ 2010.08.15</span>
<a name="line-10"></a><span class='hs-comment'>-- |</span>
<a name="line-11"></a><span class='hs-comment'>-- Module : Data.Trie.Internal</span>
<a name="line-12"></a><span class='hs-comment'>-- Copyright : Copyright (c) 2008--2011 wren ng thornton</span>
<a name="line-13"></a><span class='hs-comment'>-- License : BSD3</span>
<a name="line-14"></a><span class='hs-comment'>-- Maintainer : wren@community.haskell.org</span>
<a name="line-15"></a><span class='hs-comment'>-- Stability : provisional</span>
<a name="line-16"></a><span class='hs-comment'>-- Portability : portable (with CPP)</span>
<a name="line-17"></a><span class='hs-comment'>--</span>
<a name="line-18"></a><span class='hs-comment'>-- Internal definition of the 'Trie' data type and generic functions</span>
<a name="line-19"></a><span class='hs-comment'>-- for manipulating them. Almost everything here is re-exported</span>
<a name="line-20"></a><span class='hs-comment'>-- from "Data.Trie", which is the preferred API for users. This</span>
<a name="line-21"></a><span class='hs-comment'>-- module is for developers who need deeper (and potentially fragile)</span>
<a name="line-22"></a><span class='hs-comment'>-- access to the abstract type.</span>
<a name="line-23"></a><span class='hs-comment'>----------------------------------------------------------------</span>
<a name="line-24"></a>
<a name="line-25"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Trie</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span>
<a name="line-26"></a> <span class='hs-layout'>(</span>
<a name="line-27"></a> <span class='hs-comment'>-- * Data types</span>
<a name="line-28"></a> <span class='hs-conid'>Trie</span><span class='hs-conid'>()</span><span class='hs-layout'>,</span> <span class='hs-varid'>showTrie</span>
<a name="line-29"></a>
<a name="line-30"></a> <span class='hs-comment'>-- * Functions for 'ByteString's</span>
<a name="line-31"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>breakMaximalPrefix</span>
<a name="line-32"></a>
<a name="line-33"></a> <span class='hs-comment'>-- * Basic functions</span>
<a name="line-34"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>empty</span><span class='hs-layout'>,</span> <span class='hs-varid'>null</span><span class='hs-layout'>,</span> <span class='hs-varid'>singleton</span><span class='hs-layout'>,</span> <span class='hs-varid'>size</span>
<a name="line-35"></a>
<a name="line-36"></a> <span class='hs-comment'>-- * Conversion and folding functions</span>
<a name="line-37"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>foldrWithKey</span><span class='hs-layout'>,</span> <span class='hs-varid'>toListBy</span>
<a name="line-38"></a>
<a name="line-39"></a> <span class='hs-comment'>-- * Query functions</span>
<a name="line-40"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>lookupBy_</span><span class='hs-layout'>,</span> <span class='hs-varid'>submap</span>
<a name="line-41"></a>
<a name="line-42"></a> <span class='hs-comment'>-- * Single-value modification</span>
<a name="line-43"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>alterBy</span><span class='hs-layout'>,</span> <span class='hs-varid'>alterBy_</span><span class='hs-layout'>,</span> <span class='hs-varid'>adjustBy</span>
<a name="line-44"></a>
<a name="line-45"></a> <span class='hs-comment'>-- * Combining tries</span>
<a name="line-46"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>mergeBy</span>
<a name="line-47"></a>
<a name="line-48"></a> <span class='hs-comment'>-- * Mapping functions</span>
<a name="line-49"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>mapBy</span>
<a name="line-50"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>filterMap</span>
<a name="line-51"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>contextualMap</span>
<a name="line-52"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>contextualMap'</span>
<a name="line-53"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>contextualFilterMap</span>
<a name="line-54"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>contextualMapBy</span>
<a name="line-55"></a>
<a name="line-56"></a> <span class='hs-comment'>-- * Priority-queue functions</span>
<a name="line-57"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>minAssoc</span><span class='hs-layout'>,</span> <span class='hs-varid'>maxAssoc</span>
<a name="line-58"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>updateMinViewBy</span><span class='hs-layout'>,</span> <span class='hs-varid'>updateMaxViewBy</span>
<a name="line-59"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-60"></a>
<a name="line-61"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Prelude</span> <span class='hs-varid'>hiding</span> <span class='hs-layout'>(</span><span class='hs-varid'>null</span><span class='hs-layout'>,</span> <span class='hs-varid'>lookup</span><span class='hs-layout'>)</span>
<a name="line-62"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Prelude</span> <span class='hs-layout'>(</span><span class='hs-varid'>null</span><span class='hs-layout'>,</span> <span class='hs-varid'>lookup</span><span class='hs-layout'>)</span>
<a name="line-63"></a>
<a name="line-64"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>S</span>
<a name="line-65"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Trie</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteStringInternal</span>
<a name="line-66"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Trie</span><span class='hs-varop'>.</span><span class='hs-conid'>BitTwiddle</span>
<a name="line-67"></a>
<a name="line-68"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Binary</span>
<a name="line-69"></a>
<a name="line-70"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Monoid</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-71"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftM</span><span class='hs-layout'>,</span> <span class='hs-varid'>liftM3</span><span class='hs-layout'>,</span> <span class='hs-varid'>liftM4</span><span class='hs-layout'>)</span>
<a name="line-72"></a><span class='hs-cpp'>#ifdef APPLICATIVE_IN_BASE</span>
<a name="line-73"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Monad</span> <span class='hs-layout'>(</span><span class='hs-varid'>ap</span><span class='hs-layout'>)</span>
<a name="line-74"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Applicative</span> <span class='hs-layout'>(</span><span class='hs-conid'>Applicative</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varop'><$></span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-75"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Foldable</span> <span class='hs-layout'>(</span><span class='hs-conid'>Foldable</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-76"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Traversable</span> <span class='hs-layout'>(</span><span class='hs-conid'>Traversable</span><span class='hs-layout'>(</span><span class='hs-varid'>traverse</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-77"></a><span class='hs-cpp'>#endif</span>
<a name="line-78"></a>
<a name="line-79"></a><span class='hs-cpp'>#ifdef __GLASGOW_HASKELL__</span>
<a name="line-80"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>GHC</span><span class='hs-varop'>.</span><span class='hs-conid'>Exts</span> <span class='hs-layout'>(</span><span class='hs-varid'>build</span><span class='hs-layout'>)</span>
<a name="line-81"></a><span class='hs-cpp'>#endif</span>
<a name="line-82"></a><span class='hs-comment'>----------------------------------------------------------------</span>
<a name="line-83"></a><span class='hs-comment'>----------------------------------------------------------------</span>
<a name="line-84"></a>
<a name="line-85"></a>
<a name="line-86"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-87"></a>-- ByteString Big-endian Patricia Trie datatype
<a name="line-88"></a>---------------------------------------------------------------}</span>
<a name="line-89"></a><span class='hs-comment'>{-
<a name="line-90"></a>In our idealized representation, we use a (directed) discrete graph
<a name="line-91"></a>to represent our finite state machine. To organize the set of
<a name="line-92"></a>outgoing arcs from a given Node we have ArcSet be a big-endian
<a name="line-93"></a>patricia tree like Data.IntMap. In order to simplify things we then
<a name="line-94"></a>go through a series of derivations.
<a name="line-95"></a>
<a name="line-96"></a>data Node a = Accept a (ArcSet a)
<a name="line-97"></a> | Reject (Branch a) -- Invariant: Must be Branch
<a name="line-98"></a>data Arc a = Arc ByteString (Node a) -- Invariant: never empty string
<a name="line-99"></a>data ArcSet a = None
<a name="line-100"></a> | One {KeyElem} (Arc a)
<a name="line-101"></a> | Branch {Prefix} {Mask} (ArcSet a) (ArcSet a)
<a name="line-102"></a>data Trie a = Empty
<a name="line-103"></a> | Start ByteString (Node a) -- Maybe empty string [1]
<a name="line-104"></a>
<a name="line-105"></a>[1] If we maintain the invariants on how Nodes recurse, then we
<a name="line-106"></a>can't simply have Start(Node a) because we may have a shared prefix
<a name="line-107"></a>where the prefix itself is not Accept'ed.
<a name="line-108"></a>
<a name="line-109"></a>
<a name="line-110"></a>-- Squash Arc into One:
<a name="line-111"></a>-- (pure good)
<a name="line-112"></a>data Node a = Accept a (ArcSet a)
<a name="line-113"></a> | Reject (Branch a)
<a name="line-114"></a>data ArcSet a = None
<a name="line-115"></a> | Arc ByteString (Node a)
<a name="line-116"></a> | Branch {Prefix} {Mask} (ArcSet a) (ArcSet a)
<a name="line-117"></a>data Trie a = Empty
<a name="line-118"></a> | Start ByteString (Node a)
<a name="line-119"></a>
<a name="line-120"></a>
<a name="line-121"></a>-- Squash Node together:
<a name="line-122"></a>-- (most likely good)
<a name="line-123"></a>data Node a = Node (Maybe a) (ArcSet a)
<a name="line-124"></a>data ArcSet a = None
<a name="line-125"></a> | Arc ByteString (Node a)
<a name="line-126"></a> | Branch {Prefix} {Mask} (ArcSet a) (ArcSet a)
<a name="line-127"></a>data Trie a = Empty
<a name="line-128"></a> | Start ByteString (Node a)
<a name="line-129"></a>
<a name="line-130"></a>
<a name="line-131"></a>-- Squash Empty/None and Arc/Start together:
<a name="line-132"></a>-- (This complicates invariants about non-empty strings and Node's
<a name="line-133"></a>-- recursion, but those can be circumvented by using smart
<a name="line-134"></a>-- constructors.)
<a name="line-135"></a>data Node a = Node (Maybe a) (ArcSet a)
<a name="line-136"></a>data Trie a = Empty
<a name="line-137"></a> | Arc ByteString (Node a)
<a name="line-138"></a> | Branch {Prefix} {Mask} (Trie a) (Trie a)
<a name="line-139"></a>
<a name="line-140"></a>
<a name="line-141"></a>-- Squash Node into Arc:
<a name="line-142"></a>-- (By this point, pure good)
<a name="line-143"></a>-- Unseen invariants:
<a name="line-144"></a>-- * ByteString non-empty, unless Arc is absolute root of tree
<a name="line-145"></a>-- * If (Maybe a) is Nothing, then (Trie a) is Branch
<a name="line-146"></a>-- * With views, we could re-expand Arc into accepting and
<a name="line-147"></a>-- nonaccepting variants
<a name="line-148"></a>--
<a name="line-149"></a>-- [2] Maybe we shouldn't unpack the ByteString. We could specialize
<a name="line-150"></a>-- or inline the breakMaximalPrefix function to prevent constructing
<a name="line-151"></a>-- a new ByteString from the parts...
<a name="line-152"></a>-}</span>
<a name="line-153"></a><span class='hs-comment'>-- | A map from 'ByteString's to @a@. For all the generic functions,</span>
<a name="line-154"></a><span class='hs-comment'>-- note that tries are strict in the @Maybe@ but not in @a@.</span>
<a name="line-155"></a><span class='hs-comment'>--</span>
<a name="line-156"></a><span class='hs-comment'>-- The 'Monad' instance is strange. If a key @k1@ is a prefix of</span>
<a name="line-157"></a><span class='hs-comment'>-- other keys, then results from binding the value at @k1@ will</span>
<a name="line-158"></a><span class='hs-comment'>-- override values from longer keys when they collide. If this is</span>
<a name="line-159"></a><span class='hs-comment'>-- useful for anything, or if there's a more sensible instance, I'd</span>
<a name="line-160"></a><span class='hs-comment'>-- be curious to know.</span>
<a name="line-161"></a>
<a name="line-162"></a><a name="Trie"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Empty</span>
<a name="line-163"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Arc</span> <span class='hs-comment'>{-# UNPACK #-}</span> <span class='hs-varop'>!</span><span class='hs-conid'>ByteString</span>
<a name="line-164"></a> <span class='hs-varop'>!</span><span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-165"></a> <span class='hs-varop'>!</span><span class='hs-layout'>(</span><span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-166"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>Branch</span> <span class='hs-comment'>{-# UNPACK #-}</span> <span class='hs-varop'>!</span><span class='hs-conid'>Prefix</span>
<a name="line-167"></a> <span class='hs-comment'>{-# UNPACK #-}</span> <span class='hs-varop'>!</span><span class='hs-conid'>Mask</span>
<a name="line-168"></a> <span class='hs-varop'>!</span><span class='hs-layout'>(</span><span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-169"></a> <span class='hs-varop'>!</span><span class='hs-layout'>(</span><span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-170"></a> <span class='hs-keyword'>deriving</span> <span class='hs-conid'>Eq</span>
<a name="line-171"></a> <span class='hs-comment'>-- Prefix/Mask should be deterministic regardless of insertion order</span>
<a name="line-172"></a> <span class='hs-comment'>-- TODO: prove this is so.</span>
<a name="line-173"></a>
<a name="line-174"></a>
<a name="line-175"></a><span class='hs-comment'>-- TODO? add Ord instance like Data.Map?</span>
<a name="line-176"></a>
<a name="line-177"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-178"></a>-- Trie instances: serialization et cetera
<a name="line-179"></a>---------------------------------------------------------------}</span>
<a name="line-180"></a>
<a name="line-181"></a><span class='hs-comment'>-- This instance does not unveil the innards of our abstract type.</span>
<a name="line-182"></a><span class='hs-comment'>-- It doesn't emit truly proper Haskell code though, since ByteStrings</span>
<a name="line-183"></a><span class='hs-comment'>-- are printed as (ASCII) Strings, but that's not our fault. (Also</span>
<a name="line-184"></a><span class='hs-comment'>-- 'fromList' is in "Data.Trie" instead of here.)</span>
<a name="line-185"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Show</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Show</span> <span class='hs-layout'>(</span><span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-186"></a> <span class='hs-varid'>showsPrec</span> <span class='hs-varid'>p</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>showParen</span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-varop'>></span> <span class='hs-num'>10</span><span class='hs-layout'>)</span>
<a name="line-187"></a> <span class='hs-varop'>$</span> <span class='hs-layout'>(</span><span class='hs-str'>"Data.Trie.fromList "</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>shows</span> <span class='hs-layout'>(</span><span class='hs-varid'>toListBy</span> <span class='hs-conid'>(,)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-188"></a>
<a name="line-189"></a>
<a name="line-190"></a><a name="showTrie"></a><span class='hs-comment'>-- | Visualization fuction for debugging.</span>
<a name="line-191"></a><span class='hs-definition'>showTrie</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Show</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span>
<a name="line-192"></a><span class='hs-definition'>showTrie</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>shows'</span> <span class='hs-varid'>id</span> <span class='hs-varid'>t</span> <span class='hs-str'>""</span>
<a name="line-193"></a> <span class='hs-keyword'>where</span>
<a name="line-194"></a> <span class='hs-varid'>spaces</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>const</span> <span class='hs-chr'>' '</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-str'>""</span><span class='hs-layout'>)</span>
<a name="line-195"></a>
<a name="line-196"></a> <span class='hs-varid'>shows'</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-str'>".\n"</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span>
<a name="line-197"></a> <span class='hs-varid'>shows'</span> <span class='hs-varid'>ss</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-198"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>s'</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-str'>"--"</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>shows</span> <span class='hs-varid'>p</span> <span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-str'>","</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>shows</span> <span class='hs-varid'>m</span> <span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-str'>"-+"</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span>
<a name="line-199"></a> <span class='hs-varid'>ss'</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ss</span> <span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-varid'>tail</span> <span class='hs-layout'>(</span><span class='hs-varid'>spaces</span> <span class='hs-varid'>s'</span><span class='hs-layout'>)</span> <span class='hs-varop'>++</span><span class='hs-layout'>)</span>
<a name="line-200"></a> <span class='hs-keyword'>in</span> <span class='hs-varid'>s'</span> <span class='hs-varop'>.</span> <span class='hs-varid'>shows'</span> <span class='hs-layout'>(</span><span class='hs-varid'>ss'</span> <span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-str'>"|"</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>l</span>
<a name="line-201"></a> <span class='hs-varop'>.</span> <span class='hs-varid'>ss'</span> <span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-str'>"|\n"</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span>
<a name="line-202"></a> <span class='hs-varop'>.</span> <span class='hs-varid'>ss'</span> <span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-str'>"`"</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>shows'</span> <span class='hs-layout'>(</span><span class='hs-varid'>ss'</span> <span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-str'>" "</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span>
<a name="line-203"></a> <span class='hs-varid'>shows'</span> <span class='hs-varid'>ss</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-204"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>s'</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-str'>"--"</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>shows</span> <span class='hs-varid'>k</span>
<a name="line-205"></a> <span class='hs-varop'>.</span> <span class='hs-varid'>maybe</span> <span class='hs-varid'>id</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>v</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-str'>"-("</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>shows</span> <span class='hs-varid'>v</span> <span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-str'>")"</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>mv</span>
<a name="line-206"></a> <span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-str'>"--"</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span>
<a name="line-207"></a> <span class='hs-keyword'>in</span> <span class='hs-varid'>s'</span> <span class='hs-varop'>.</span> <span class='hs-varid'>shows'</span> <span class='hs-layout'>(</span><span class='hs-varid'>ss</span> <span class='hs-varop'>.</span> <span class='hs-layout'>(</span><span class='hs-varid'>spaces</span> <span class='hs-varid'>s'</span> <span class='hs-varop'>++</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>t'</span>
<a name="line-208"></a>
<a name="line-209"></a>
<a name="line-210"></a><span class='hs-comment'>-- TODO?? a Read instance? hrm... should I?</span>
<a name="line-211"></a>
<a name="line-212"></a><span class='hs-comment'>-- TODO: consider an instance more like the new one for Data.Map. Better?</span>
<a name="line-213"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Binary</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Binary</span> <span class='hs-layout'>(</span><span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-214"></a> <span class='hs-varid'>put</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>put</span> <span class='hs-layout'>(</span><span class='hs-num'>0</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word8</span><span class='hs-layout'>)</span>
<a name="line-215"></a> <span class='hs-varid'>put</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>m</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>put</span> <span class='hs-layout'>(</span><span class='hs-num'>1</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word8</span><span class='hs-layout'>)</span><span class='hs-layout'>;</span> <span class='hs-varid'>put</span> <span class='hs-varid'>k</span><span class='hs-layout'>;</span> <span class='hs-varid'>put</span> <span class='hs-varid'>m</span><span class='hs-layout'>;</span> <span class='hs-varid'>put</span> <span class='hs-varid'>t</span>
<a name="line-216"></a> <span class='hs-varid'>put</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>put</span> <span class='hs-layout'>(</span><span class='hs-num'>2</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Word8</span><span class='hs-layout'>)</span><span class='hs-layout'>;</span> <span class='hs-varid'>put</span> <span class='hs-varid'>p</span><span class='hs-layout'>;</span> <span class='hs-varid'>put</span> <span class='hs-varid'>m</span><span class='hs-layout'>;</span> <span class='hs-varid'>put</span> <span class='hs-varid'>l</span><span class='hs-layout'>;</span> <span class='hs-varid'>put</span> <span class='hs-varid'>r</span>
<a name="line-217"></a>
<a name="line-218"></a> <span class='hs-varid'>get</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>tag</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>get</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Get</span> <span class='hs-conid'>Word8</span>
<a name="line-219"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>tag</span> <span class='hs-keyword'>of</span>
<a name="line-220"></a> <span class='hs-num'>0</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>Empty</span>
<a name="line-221"></a> <span class='hs-num'>1</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>liftM3</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>get</span> <span class='hs-varid'>get</span> <span class='hs-varid'>get</span>
<a name="line-222"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>liftM4</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>get</span> <span class='hs-varid'>get</span> <span class='hs-varid'>get</span> <span class='hs-varid'>get</span>
<a name="line-223"></a>
<a name="line-224"></a>
<a name="line-225"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-226"></a>-- Trie instances: Abstract Nonsense
<a name="line-227"></a>---------------------------------------------------------------}</span>
<a name="line-228"></a>
<a name="line-229"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Functor</span> <span class='hs-conid'>Trie</span> <span class='hs-keyword'>where</span>
<a name="line-230"></a> <span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span>
<a name="line-231"></a> <span class='hs-keyword'>where</span>
<a name="line-232"></a> <span class='hs-varid'>go</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Empty</span>
<a name="line-233"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-234"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-235"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-236"></a>
<a name="line-237"></a>
<a name="line-238"></a><span class='hs-cpp'>#ifdef APPLICATIVE_IN_BASE</span>
<a name="line-239"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Foldable</span> <span class='hs-conid'>Trie</span> <span class='hs-keyword'>where</span>
<a name="line-240"></a> <span class='hs-comment'>-- If our definition of foldr is so much faster than the Endo</span>
<a name="line-241"></a> <span class='hs-comment'>-- default, then maybe we should remove this and use the default</span>
<a name="line-242"></a> <span class='hs-comment'>-- foldMap based on foldr</span>
<a name="line-243"></a> <span class='hs-varid'>foldMap</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span>
<a name="line-244"></a> <span class='hs-keyword'>where</span>
<a name="line-245"></a> <span class='hs-varid'>go</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mempty</span>
<a name="line-246"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>t</span>
<a name="line-247"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>v</span> <span class='hs-varop'>`mappend`</span> <span class='hs-varid'>go</span> <span class='hs-varid'>t</span>
<a name="line-248"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>l</span> <span class='hs-varop'>`mappend`</span> <span class='hs-varid'>go</span> <span class='hs-varid'>r</span>
<a name="line-249"></a>
<a name="line-250"></a> <span class='hs-comment'>{- This definition is much faster, but it's also wrong
<a name="line-251"></a> -- (or at least different than foldrWithKey)
<a name="line-252"></a> foldr f = \z t -> go t id z
<a name="line-253"></a> where
<a name="line-254"></a> go Empty k x = k x
<a name="line-255"></a> go (Branch _ _ l r) k x = go r (go l k) x
<a name="line-256"></a> go (Arc _ Nothing t) k x = go t k x
<a name="line-257"></a> go (Arc _ (Just v) t) k x = go t k (f v x)
<a name="line-258"></a>
<a name="line-259"></a> foldl f = \z t -> go t id z
<a name="line-260"></a> where
<a name="line-261"></a> go Empty k x = k x
<a name="line-262"></a> go (Branch _ _ l r) k x = go l (go r k) x
<a name="line-263"></a> go (Arc _ Nothing t) k x = go t k x
<a name="line-264"></a> go (Arc _ (Just v) t) k x = go t k (f x v)
<a name="line-265"></a> -}</span>
<a name="line-266"></a>
<a name="line-267"></a><span class='hs-comment'>-- TODO: newtype Keys = K Trie ; instance Foldable Keys</span>
<a name="line-268"></a><span class='hs-comment'>-- TODO: newtype Assoc = A Trie ; instance Foldable Assoc</span>
<a name="line-269"></a>
<a name="line-270"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Traversable</span> <span class='hs-conid'>Trie</span> <span class='hs-keyword'>where</span>
<a name="line-271"></a> <span class='hs-varid'>traverse</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span>
<a name="line-272"></a> <span class='hs-keyword'>where</span>
<a name="line-273"></a> <span class='hs-varid'>go</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pure</span> <span class='hs-conid'>Empty</span>
<a name="line-274"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varop'><$></span> <span class='hs-varid'>go</span> <span class='hs-varid'>t</span>
<a name="line-275"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-varop'>.</span> <span class='hs-conid'>Just</span> <span class='hs-varop'><$></span> <span class='hs-varid'>f</span> <span class='hs-varid'>v</span> <span class='hs-varop'><*></span> <span class='hs-varid'>go</span> <span class='hs-varid'>t</span>
<a name="line-276"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varop'><$></span> <span class='hs-varid'>go</span> <span class='hs-varid'>l</span> <span class='hs-varop'><*></span> <span class='hs-varid'>go</span> <span class='hs-varid'>r</span>
<a name="line-277"></a>
<a name="line-278"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Applicative</span> <span class='hs-conid'>Trie</span> <span class='hs-keyword'>where</span>
<a name="line-279"></a> <span class='hs-varid'>pure</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span>
<a name="line-280"></a> <span class='hs-layout'>(</span><span class='hs-varop'><*></span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ap</span>
<a name="line-281"></a><span class='hs-cpp'>#endif</span>
<a name="line-282"></a>
<a name="line-283"></a><span class='hs-comment'>-- Does this even make sense? It's not nondeterminism like lists</span>
<a name="line-284"></a><span class='hs-comment'>-- and sets. If no keys were prefixes of other keys it'd make sense</span>
<a name="line-285"></a><span class='hs-comment'>-- as a decision-tree; but since keys /can/ prefix, tries formed</span>
<a name="line-286"></a><span class='hs-comment'>-- from shorter keys can shadow the results from longer keys due</span>
<a name="line-287"></a><span class='hs-comment'>-- to the 'unionL'. It does seem to follow the laws though... What</span>
<a name="line-288"></a><span class='hs-comment'>-- computation could this possibly represent?</span>
<a name="line-289"></a><span class='hs-comment'>--</span>
<a name="line-290"></a><span class='hs-comment'>-- 1. return x >>= f == f x</span>
<a name="line-291"></a><span class='hs-comment'>-- 2. m >>= return == m</span>
<a name="line-292"></a><span class='hs-comment'>-- 3. (m >>= f) >>= g == m >>= (\x -> f x >>= g)</span>
<a name="line-293"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Monad</span> <span class='hs-conid'>Trie</span> <span class='hs-keyword'>where</span>
<a name="line-294"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>singleton</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>empty</span> <span class='hs-varid'>x</span>
<a name="line-295"></a>
<a name="line-296"></a> <span class='hs-layout'>(</span><span class='hs-varop'>>>=</span><span class='hs-layout'>)</span> <span class='hs-conid'>Empty</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>empty</span>
<a name="line-297"></a> <span class='hs-layout'>(</span><span class='hs-varop'>>>=</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>l</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>r</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
<a name="line-298"></a> <span class='hs-layout'>(</span><span class='hs-varop'>>>=</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-varid'>t</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
<a name="line-299"></a> <span class='hs-layout'>(</span><span class='hs-varop'>>>=</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>v</span> <span class='hs-varop'>`unionL`</span> <span class='hs-layout'>(</span><span class='hs-varid'>t</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-300"></a> <span class='hs-keyword'>where</span>
<a name="line-301"></a> <span class='hs-varid'>unionL</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mergeBy</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>x</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Just</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-302"></a>
<a name="line-303"></a>
<a name="line-304"></a><span class='hs-comment'>-- This instance is more sensible than Data.IntMap and Data.Map's</span>
<a name="line-305"></a><span class='hs-keyword'>instance</span> <span class='hs-layout'>(</span><span class='hs-conid'>Monoid</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Monoid</span> <span class='hs-layout'>(</span><span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-306"></a> <span class='hs-varid'>mempty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>empty</span>
<a name="line-307"></a> <span class='hs-varid'>mappend</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mergeBy</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varop'>`mappend`</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span>
<a name="line-308"></a>
<a name="line-309"></a>
<a name="line-310"></a><span class='hs-comment'>-- Since the Monoid instance isn't natural in @a@, I can't think</span>
<a name="line-311"></a><span class='hs-comment'>-- of any other sensible instance for MonadPlus. It's as specious</span>
<a name="line-312"></a><span class='hs-comment'>-- as Maybe, IO, and STM's instances though.</span>
<a name="line-313"></a><span class='hs-comment'>--</span>
<a name="line-314"></a><span class='hs-comment'>-- MonadPlus laws: <<a href="http://www.haskell.org/haskellwiki/MonadPlus">http://www.haskell.org/haskellwiki/MonadPlus</a>></span>
<a name="line-315"></a><span class='hs-comment'>-- 1. <Trie a, mzero, mplus> forms a monoid</span>
<a name="line-316"></a><span class='hs-comment'>-- 2. mzero >>= f === mzero</span>
<a name="line-317"></a><span class='hs-comment'>-- 3. m >> mzero === mzero</span>
<a name="line-318"></a><span class='hs-comment'>-- 4. mplus m n >>= k === mplus (m >>= k) (n >>= k)</span>
<a name="line-319"></a><span class='hs-comment'>-- 4' mplus (return a) n === return a</span>
<a name="line-320"></a><span class='hs-comment'>{-
<a name="line-321"></a>-- Follows #1, #1, and #3. But it does something like 4' instead
<a name="line-322"></a>-- of actually doing #4 (since we'd merge the trees generated by
<a name="line-323"></a>-- @k@ for conflicting values)
<a name="line-324"></a>--
<a name="line-325"></a>-- TODO: cf Control.Applicative.Alternative (base-4, but not Hugs).
<a name="line-326"></a>-- But (<*>) gets odd when the function is not 'pure'... maybe
<a name="line-327"></a>-- helpful though.
<a name="line-328"></a>instance MonadPlus Trie where
<a name="line-329"></a> mzero = empty
<a name="line-330"></a> mplus = unionL where unionL = mergeBy (\x _ -> Just x)
<a name="line-331"></a>-}</span>
<a name="line-332"></a>
<a name="line-333"></a>
<a name="line-334"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-335"></a>-- Extra mapping functions
<a name="line-336"></a>---------------------------------------------------------------}</span>
<a name="line-337"></a>
<a name="line-338"></a><a name="filterMap"></a><span class='hs-comment'>-- | Apply a function to all values, potentially removing them.</span>
<a name="line-339"></a><span class='hs-definition'>filterMap</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>b</span>
<a name="line-340"></a><span class='hs-definition'>filterMap</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span>
<a name="line-341"></a> <span class='hs-keyword'>where</span>
<a name="line-342"></a> <span class='hs-varid'>go</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>empty</span>
<a name="line-343"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-344"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-345"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-346"></a>
<a name="line-347"></a>
<a name="line-348"></a><a name="mapBy"></a><span class='hs-comment'>-- | Generic version of 'fmap'. This function is notably more</span>
<a name="line-349"></a><span class='hs-comment'>-- expensive than 'fmap' or 'filterMap' because we have to reconstruct</span>
<a name="line-350"></a><span class='hs-comment'>-- the keys.</span>
<a name="line-351"></a><span class='hs-definition'>mapBy</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>b</span>
<a name="line-352"></a><span class='hs-definition'>mapBy</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>empty</span>
<a name="line-353"></a> <span class='hs-keyword'>where</span>
<a name="line-354"></a> <span class='hs-varid'>go</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>empty</span>
<a name="line-355"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q'</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>q'</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span>
<a name="line-356"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>q'</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q'</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <span class='hs-varid'>q'</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span>
<a name="line-357"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-358"></a>
<a name="line-359"></a>
<a name="line-360"></a><a name="contextualMap"></a><span class='hs-comment'>-- | A variant of 'fmap' which provides access to the subtrie rooted</span>
<a name="line-361"></a><span class='hs-comment'>-- at each value.</span>
<a name="line-362"></a><span class='hs-definition'>contextualMap</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>b</span>
<a name="line-363"></a><span class='hs-definition'>contextualMap</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span>
<a name="line-364"></a> <span class='hs-keyword'>where</span>
<a name="line-365"></a> <span class='hs-varid'>go</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Empty</span>
<a name="line-366"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-367"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>v</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-368"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-369"></a>
<a name="line-370"></a>
<a name="line-371"></a><a name="contextualMap'"></a><span class='hs-comment'>-- | A variant of 'contextualMap' which applies the function strictly.</span>
<a name="line-372"></a><span class='hs-definition'>contextualMap'</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>b</span>
<a name="line-373"></a><span class='hs-definition'>contextualMap'</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span>
<a name="line-374"></a> <span class='hs-keyword'>where</span>
<a name="line-375"></a> <span class='hs-varid'>go</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Empty</span>
<a name="line-376"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-377"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varop'>$!</span> <span class='hs-varid'>f</span> <span class='hs-varid'>v</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-378"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-379"></a>
<a name="line-380"></a>
<a name="line-381"></a><a name="contextualFilterMap"></a><span class='hs-comment'>-- | A contextual variant of 'filterMap'.</span>
<a name="line-382"></a><span class='hs-definition'>contextualFilterMap</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>b</span>
<a name="line-383"></a><span class='hs-definition'>contextualFilterMap</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span>
<a name="line-384"></a> <span class='hs-keyword'>where</span>
<a name="line-385"></a> <span class='hs-varid'>go</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>empty</span>
<a name="line-386"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-387"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>v</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-388"></a> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-389"></a>
<a name="line-390"></a>
<a name="line-391"></a><a name="contextualMapBy"></a><span class='hs-comment'>-- | A contextual variant of 'mapBy'. Again note that this is</span>
<a name="line-392"></a><span class='hs-comment'>-- expensive since we must reconstruct the keys.</span>
<a name="line-393"></a><span class='hs-definition'>contextualMapBy</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>b</span>
<a name="line-394"></a><span class='hs-definition'>contextualMapBy</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>empty</span>
<a name="line-395"></a> <span class='hs-keyword'>where</span>
<a name="line-396"></a> <span class='hs-varid'>go</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>empty</span>
<a name="line-397"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-398"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>q'</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span>
<a name="line-399"></a> <span class='hs-keyword'>in</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>q'</span> <span class='hs-varid'>v</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q'</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-400"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-401"></a>
<a name="line-402"></a>
<a name="line-403"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-404"></a>-- Smart constructors and helper functions for building tries
<a name="line-405"></a>---------------------------------------------------------------}</span>
<a name="line-406"></a>
<a name="line-407"></a><a name="branch"></a><span class='hs-comment'>-- | Smart constructor to prune @Empty@ from @Branch@es.</span>
<a name="line-408"></a><span class='hs-definition'>branch</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Prefix</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Mask</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span>
<a name="line-409"></a><span class='hs-comment'>{-# INLINE branch #-}</span>
<a name="line-410"></a><span class='hs-definition'>branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>r</span>
<a name="line-411"></a><span class='hs-definition'>branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>l</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>l</span>
<a name="line-412"></a><span class='hs-definition'>branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span>
<a name="line-413"></a>
<a name="line-414"></a>
<a name="line-415"></a><a name="arc"></a><span class='hs-comment'>-- | Smart constructor to prune @Arc@s that lead nowhere.</span>
<a name="line-416"></a><span class='hs-comment'>-- N.B if mv=Just then doesn't check whether t=epsilon. It's up to callers to ensure that invariant isn't broken.</span>
<a name="line-417"></a><span class='hs-definition'>arc</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span>
<a name="line-418"></a><span class='hs-comment'>{-# INLINE arc #-}</span>
<a name="line-419"></a><span class='hs-definition'>arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span>
<a name="line-420"></a><span class='hs-definition'>arc</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Nothing</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Empty</span>
<a name="line-421"></a><span class='hs-definition'>arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t</span>
<a name="line-422"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span>
<a name="line-423"></a><span class='hs-definition'>arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k'</span> <span class='hs-varid'>mv'</span> <span class='hs-varid'>t'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>k</span> <span class='hs-varid'>k'</span><span class='hs-layout'>)</span> <span class='hs-varid'>mv'</span> <span class='hs-varid'>t'</span>
<a name="line-424"></a>
<a name="line-425"></a>
<a name="line-426"></a><a name="branchMerge"></a><span class='hs-comment'>-- | Smart constructor to join two tries into a @Branch@ with maximal</span>
<a name="line-427"></a><span class='hs-comment'>-- prefix sharing. Requires knowing the prefixes, but can combine</span>
<a name="line-428"></a><span class='hs-comment'>-- either @Branch@es or @Arc@s.</span>
<a name="line-429"></a><span class='hs-comment'>--</span>
<a name="line-430"></a><span class='hs-comment'>-- N.B. /do not/ use if prefixes could match entirely!</span>
<a name="line-431"></a><span class='hs-definition'>branchMerge</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Prefix</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Prefix</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span>
<a name="line-432"></a><span class='hs-comment'>{-# INLINE branchMerge #-}</span>
<a name="line-433"></a><span class='hs-definition'>branchMerge</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>t2</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t2</span>
<a name="line-434"></a><span class='hs-definition'>branchMerge</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>t1</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t1</span>
<a name="line-435"></a><span class='hs-definition'>branchMerge</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>t1</span> <span class='hs-varid'>p2</span> <span class='hs-varid'>t2</span>
<a name="line-436"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>zero</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>t1</span> <span class='hs-varid'>t2</span>
<a name="line-437"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>t2</span> <span class='hs-varid'>t1</span>
<a name="line-438"></a> <span class='hs-keyword'>where</span>
<a name="line-439"></a> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branchMask</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>p2</span>
<a name="line-440"></a> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mask</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>m</span>
<a name="line-441"></a>
<a name="line-442"></a>
<a name="line-443"></a><a name="getPrefix"></a><span class='hs-comment'>-- It would be better if Arc used</span>
<a name="line-444"></a><span class='hs-comment'>-- Data.ByteString.TrieInternal.wordHead somehow, that way</span>
<a name="line-445"></a><span class='hs-comment'>-- we can see 4/8/?*Word8 at a time instead of just one.</span>
<a name="line-446"></a><span class='hs-comment'>-- But that makes maintaining invariants ...difficult :(</span>
<a name="line-447"></a><span class='hs-definition'>getPrefix</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Prefix</span>
<a name="line-448"></a><span class='hs-comment'>{-# INLINE getPrefix #-}</span>
<a name="line-449"></a><span class='hs-definition'>getPrefix</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>p</span>
<a name="line-450"></a><span class='hs-definition'>getPrefix</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>0</span> <span class='hs-comment'>-- for lack of a better value</span>
<a name="line-451"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>head</span> <span class='hs-varid'>k</span>
<a name="line-452"></a><span class='hs-definition'>getPrefix</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-str'>"getPrefix: no Prefix of Empty"</span>
<a name="line-453"></a>
<a name="line-454"></a>
<a name="line-455"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-456"></a>-- Error messages
<a name="line-457"></a>---------------------------------------------------------------}</span>
<a name="line-458"></a>
<a name="line-459"></a><a name="errorLogHead"></a><span class='hs-comment'>-- TODO: shouldn't we inline the logic and just NOINLINE the string constant? There are only three use sites, which themselves aren't inlined...</span>
<a name="line-460"></a><span class='hs-definition'>errorLogHead</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ByteStringElem</span>
<a name="line-461"></a><span class='hs-comment'>{-# NOINLINE errorLogHead #-}</span>
<a name="line-462"></a><span class='hs-definition'>errorLogHead</span> <span class='hs-varid'>fn</span> <span class='hs-varid'>q</span>
<a name="line-463"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>q</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>error</span> <span class='hs-varop'>$</span> <span class='hs-str'>"Data.Trie.Internal."</span> <span class='hs-varop'>++</span> <span class='hs-varid'>fn</span> <span class='hs-varop'>++</span><span class='hs-str'>": found null subquery"</span>
<a name="line-464"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>head</span> <span class='hs-varid'>q</span>
<a name="line-465"></a>
<a name="line-466"></a>
<a name="line-467"></a><span class='hs-comment'>----------------------------------------------------------------</span>
<a name="line-468"></a><span class='hs-comment'>----------------------------------------------------------------</span>
<a name="line-469"></a>
<a name="line-470"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-471"></a>-- Basic functions
<a name="line-472"></a>---------------------------------------------------------------}</span>
<a name="line-473"></a>
<a name="line-474"></a><a name="empty"></a><span class='hs-comment'>-- | /O(1)/, Construct the empty trie.</span>
<a name="line-475"></a><span class='hs-definition'>empty</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span>
<a name="line-476"></a><span class='hs-comment'>{-# INLINE empty #-}</span>
<a name="line-477"></a><span class='hs-definition'>empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Empty</span>
<a name="line-478"></a>
<a name="line-479"></a>
<a name="line-480"></a><a name="null"></a><span class='hs-comment'>-- | /O(1)/, Is the trie empty?</span>
<a name="line-481"></a><span class='hs-definition'>null</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-482"></a><span class='hs-comment'>{-# INLINE null #-}</span>
<a name="line-483"></a><span class='hs-definition'>null</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span>
<a name="line-484"></a><span class='hs-definition'>null</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>False</span>
<a name="line-485"></a>
<a name="line-486"></a>
<a name="line-487"></a><a name="singleton"></a><span class='hs-comment'>-- | /O(1)/, Construct a singleton trie.</span>
<a name="line-488"></a><span class='hs-definition'>singleton</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span>
<a name="line-489"></a><span class='hs-comment'>{-# INLINE singleton #-}</span>
<a name="line-490"></a><span class='hs-definition'>singleton</span> <span class='hs-varid'>k</span> <span class='hs-varid'>v</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-conid'>Empty</span>
<a name="line-491"></a><span class='hs-comment'>-- For singletons, don't need to verify invariant on arc length >0</span>
<a name="line-492"></a>
<a name="line-493"></a>
<a name="line-494"></a><a name="size"></a><span class='hs-comment'>-- | /O(n)/, Get count of elements in trie.</span>
<a name="line-495"></a><span class='hs-definition'>size</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span>
<a name="line-496"></a><span class='hs-comment'>{-# INLINE size #-}</span>
<a name="line-497"></a><span class='hs-definition'>size</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>size'</span> <span class='hs-varid'>t</span> <span class='hs-varid'>id</span> <span class='hs-num'>0</span>
<a name="line-498"></a>
<a name="line-499"></a><a name="size'"></a><span class='hs-comment'>-- | /O(n)/, CPS accumulator helper for calculating 'size'.</span>
<a name="line-500"></a><span class='hs-definition'>size'</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span>
<a name="line-501"></a><span class='hs-definition'>size'</span> <span class='hs-conid'>Empty</span> <span class='hs-varid'>f</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>n</span>
<a name="line-502"></a><span class='hs-definition'>size'</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-varid'>f</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>size'</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-varid'>size'</span> <span class='hs-varid'>r</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-varid'>n</span>
<a name="line-503"></a><span class='hs-definition'>size'</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-varid'>f</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>size'</span> <span class='hs-varid'>t</span> <span class='hs-varid'>f</span> <span class='hs-varid'>n</span>
<a name="line-504"></a><span class='hs-definition'>size'</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-varid'>f</span> <span class='hs-varid'>n</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>size'</span> <span class='hs-varid'>t</span> <span class='hs-varid'>f</span> <span class='hs-varop'>$!</span> <span class='hs-varid'>n</span> <span class='hs-varop'>+</span> <span class='hs-num'>1</span>
<a name="line-505"></a>
<a name="line-506"></a>
<a name="line-507"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-508"></a>-- Conversion functions
<a name="line-509"></a>---------------------------------------------------------------}</span>
<a name="line-510"></a>
<a name="line-511"></a><a name="foldrWithKey"></a><span class='hs-comment'>-- Still rather inefficient</span>
<a name="line-512"></a><span class='hs-comment'>-- </span>
<a name="line-513"></a><span class='hs-comment'>-- TODO: rewrite list-catenation to be lazier (real CPS instead of</span>
<a name="line-514"></a><span class='hs-comment'>-- function building? is the function building really better than</span>
<a name="line-515"></a><span class='hs-comment'>-- (++) anyways?)</span>
<a name="line-516"></a><span class='hs-comment'>-- N.B. If our manual definition of foldr/foldl (using function</span>
<a name="line-517"></a><span class='hs-comment'>-- application) is so much faster than the default Endo definition</span>
<a name="line-518"></a><span class='hs-comment'>-- (using function composition), then we should make this use</span>
<a name="line-519"></a><span class='hs-comment'>-- application instead too.</span>
<a name="line-520"></a><span class='hs-comment'>--</span>
<a name="line-521"></a><span class='hs-comment'>-- TODO: the @q@ accumulator should be lazy ByteString and only</span>
<a name="line-522"></a><span class='hs-comment'>-- forced by @fcons@. It's already non-strict, but we should ensure</span>
<a name="line-523"></a><span class='hs-comment'>-- O(n) not O(n^2) when it's forced.</span>
<a name="line-524"></a><span class='hs-comment'>--</span>
<a name="line-525"></a><span class='hs-comment'>-- BUG: not safe for deep strict @fcons@, only for WHNF-strict like (:)</span>
<a name="line-526"></a><span class='hs-comment'>-- Where to put the strictness to amortize it?</span>
<a name="line-527"></a><span class='hs-comment'>--</span>
<a name="line-528"></a><span class='hs-comment'>-- | Convert a trie into a list (in key-sorted order) using a</span>
<a name="line-529"></a><span class='hs-comment'>-- function, folding the list as we go.</span>
<a name="line-530"></a><span class='hs-definition'>foldrWithKey</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span>
<a name="line-531"></a><span class='hs-definition'>foldrWithKey</span> <span class='hs-varid'>fcons</span> <span class='hs-varid'>nil</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>t</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>go</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>empty</span> <span class='hs-varid'>t</span> <span class='hs-varid'>nil</span>
<a name="line-532"></a> <span class='hs-keyword'>where</span>
<a name="line-533"></a> <span class='hs-varid'>go</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span>
<a name="line-534"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>l</span> <span class='hs-varop'>.</span> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>r</span>
<a name="line-535"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-536"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>mv</span> <span class='hs-keyword'>of</span>
<a name="line-537"></a> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>rest</span>
<a name="line-538"></a> <span class='hs-conid'>Just</span> <span class='hs-varid'>v</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>fcons</span> <span class='hs-varid'>k'</span> <span class='hs-varid'>v</span> <span class='hs-varop'>.</span> <span class='hs-varid'>rest</span>
<a name="line-539"></a> <span class='hs-keyword'>where</span>
<a name="line-540"></a> <span class='hs-varid'>rest</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>k'</span> <span class='hs-varid'>t</span>
<a name="line-541"></a> <span class='hs-varid'>k'</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span>
<a name="line-542"></a>
<a name="line-543"></a>
<a name="line-544"></a><a name="toListBy"></a><span class='hs-comment'>-- cf Data.ByteString.unpack</span>
<a name="line-545"></a><span class='hs-comment'>-- <<a href="http://hackage.haskell.org/packages/archive/bytestring/0.9.1.4/doc/html/src/Data-ByteString.html">http://hackage.haskell.org/packages/archive/bytestring/0.9.1.4/doc/html/src/Data-ByteString.html</a>></span>
<a name="line-546"></a><span class='hs-comment'>--</span>
<a name="line-547"></a><span class='hs-comment'>-- | Convert a trie into a list using a function. Resulting values</span>
<a name="line-548"></a><span class='hs-comment'>-- are in key-sorted order.</span>
<a name="line-549"></a><span class='hs-definition'>toListBy</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span>
<a name="line-550"></a><span class='hs-comment'>{-# INLINE toListBy #-}</span>
<a name="line-551"></a><span class='hs-cpp'>#if !defined(__GLASGOW_HASKELL__)</span>
<a name="line-552"></a><span class='hs-comment'>-- TODO: should probably inline foldrWithKey</span>
<a name="line-553"></a><span class='hs-comment'>-- TODO: compare performance of that vs both this and the GHC version</span>
<a name="line-554"></a><span class='hs-definition'>toListBy</span> <span class='hs-varid'>f</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldrWithKey</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-conop'>:</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-conid'>[]</span> <span class='hs-varid'>t</span>
<a name="line-555"></a><span class='hs-cpp'>#else</span>
<a name="line-556"></a><span class='hs-comment'>-- Written with 'build' to enable the build\/foldr fusion rules.</span>
<a name="line-557"></a><span class='hs-definition'>toListBy</span> <span class='hs-varid'>f</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>build</span> <span class='hs-layout'>(</span><span class='hs-varid'>toListByFB</span> <span class='hs-varid'>f</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-558"></a>
<a name="line-559"></a><a name="toListByFB"></a><span class='hs-comment'>-- TODO: should probably have a specialized version for strictness,</span>
<a name="line-560"></a><span class='hs-comment'>-- and a rule to rewrite generic lazy version into it. As per</span>
<a name="line-561"></a><span class='hs-comment'>-- Data.ByteString.unpack and the comments there about strictness</span>
<a name="line-562"></a><span class='hs-comment'>-- and fusion.</span>
<a name="line-563"></a><span class='hs-definition'>toListByFB</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>c</span>
<a name="line-564"></a><span class='hs-comment'>{-# INLINE [0] toListByFB #-}</span>
<a name="line-565"></a><span class='hs-definition'>toListByFB</span> <span class='hs-varid'>f</span> <span class='hs-varid'>t</span> <span class='hs-varid'>cons</span> <span class='hs-varid'>nil</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>foldrWithKey</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>cons</span> <span class='hs-varop'>.</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span> <span class='hs-varid'>nil</span> <span class='hs-varid'>t</span>
<a name="line-566"></a><span class='hs-cpp'>#endif</span>
<a name="line-567"></a>
<a name="line-568"></a>
<a name="line-569"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-570"></a>-- Query functions (just recurse)
<a name="line-571"></a>---------------------------------------------------------------}</span>
<a name="line-572"></a>
<a name="line-573"></a><a name="lookupBy_"></a><span class='hs-comment'>-- | Generic function to find a value (if it exists) and the subtrie</span>
<a name="line-574"></a><span class='hs-comment'>-- rooted at the prefix. The first function argument is called if and</span>
<a name="line-575"></a><span class='hs-comment'>-- only if a node is exactly reachable by the query; if no node is</span>
<a name="line-576"></a><span class='hs-comment'>-- exactly reachable the default value is used; if the middle of</span>
<a name="line-577"></a><span class='hs-comment'>-- an arc is reached, the second function argument is used.</span>
<a name="line-578"></a><span class='hs-comment'>--</span>
<a name="line-579"></a><span class='hs-comment'>-- This function is intended for internal use. For the public-facing</span>
<a name="line-580"></a><span class='hs-comment'>-- version, see @lookupBy@ in "Data.Trie".</span>
<a name="line-581"></a><span class='hs-definition'>lookupBy_</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-582"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span>
<a name="line-583"></a><span class='hs-definition'>lookupBy_</span> <span class='hs-varid'>f</span> <span class='hs-varid'>z</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lookupBy_'</span>
<a name="line-584"></a> <span class='hs-keyword'>where</span>
<a name="line-585"></a> <span class='hs-comment'>-- | Deal with epsilon query (when there is no epsilon value)</span>
<a name="line-586"></a> <span class='hs-varid'>lookupBy_'</span> <span class='hs-varid'>q</span> <span class='hs-varid'>t</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>q</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span>
<a name="line-587"></a> <span class='hs-varid'>lookupBy_'</span> <span class='hs-varid'>q</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>t</span>
<a name="line-588"></a>
<a name="line-589"></a> <span class='hs-comment'>-- | The main recursion</span>
<a name="line-590"></a> <span class='hs-varid'>go</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>z</span>
<a name="line-591"></a>
<a name="line-592"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-593"></a> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span><span class='hs-varid'>k'</span><span class='hs-layout'>,</span><span class='hs-varid'>q'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>breakMaximalPrefix</span> <span class='hs-varid'>k</span> <span class='hs-varid'>q</span>
<a name="line-594"></a> <span class='hs-keyword'>in</span> <span class='hs-keyword'>case</span> <span class='hs-layout'>(</span><span class='hs-varid'>not</span> <span class='hs-varop'>$</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k'</span><span class='hs-layout'>,</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>q'</span><span class='hs-layout'>)</span> <span class='hs-keyword'>of</span>
<a name="line-595"></a> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k'</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-596"></a> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-conid'>False</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>z</span>
<a name="line-597"></a> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span> <span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>f</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span>
<a name="line-598"></a> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span> <span class='hs-conid'>False</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>go</span> <span class='hs-varid'>q'</span> <span class='hs-varid'>t</span>
<a name="line-599"></a>
<a name="line-600"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>t_</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>findArc</span> <span class='hs-varid'>t_</span>
<a name="line-601"></a> <span class='hs-keyword'>where</span>
<a name="line-602"></a> <span class='hs-varid'>qh</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>errorLogHead</span> <span class='hs-str'>"lookupBy_"</span> <span class='hs-varid'>q</span>
<a name="line-603"></a>
<a name="line-604"></a> <span class='hs-comment'>-- | /O(min(m,W))/, where /m/ is number of @Arc@s in this</span>
<a name="line-605"></a> <span class='hs-comment'>-- branching, and /W/ is the word size of the Prefix,Mask type.</span>
<a name="line-606"></a> <span class='hs-varid'>findArc</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-607"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>nomatch</span> <span class='hs-varid'>qh</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>z</span>
<a name="line-608"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>zero</span> <span class='hs-varid'>qh</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>findArc</span> <span class='hs-varid'>l</span>
<a name="line-609"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>findArc</span> <span class='hs-varid'>r</span>
<a name="line-610"></a> <span class='hs-varid'>findArc</span> <span class='hs-varid'>t</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>t</span>
<a name="line-611"></a> <span class='hs-varid'>findArc</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>z</span>
<a name="line-612"></a>
<a name="line-613"></a>
<a name="line-614"></a><a name="submap"></a><span class='hs-comment'>-- This function needs to be here, not in "Data.Trie", because of</span>
<a name="line-615"></a><span class='hs-comment'>-- 'arc' which isn't exported. We could use the monad instance</span>
<a name="line-616"></a><span class='hs-comment'>-- instead, though it'd be far more circuitous.</span>
<a name="line-617"></a><span class='hs-comment'>-- arc k Nothing t === singleton k () >> t</span>
<a name="line-618"></a><span class='hs-comment'>-- arc k (Just v) t === singleton k v >>= unionR t . singleton S.empty</span>
<a name="line-619"></a><span class='hs-comment'>-- (...except 'arc' doesn't do the invariant correction</span>
<a name="line-620"></a><span class='hs-comment'>-- of (>>=) for epsilon`elem`t)</span>
<a name="line-621"></a><span class='hs-comment'>--</span>
<a name="line-622"></a><span class='hs-comment'>-- | Return the subtrie containing all keys beginning with a prefix.</span>
<a name="line-623"></a><span class='hs-definition'>submap</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span>
<a name="line-624"></a><span class='hs-comment'>{-# INLINE submap #-}</span>
<a name="line-625"></a><span class='hs-definition'>submap</span> <span class='hs-varid'>q</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lookupBy_</span> <span class='hs-layout'>(</span><span class='hs-varid'>arc</span> <span class='hs-varid'>q</span><span class='hs-layout'>)</span> <span class='hs-varid'>empty</span> <span class='hs-layout'>(</span><span class='hs-varid'>arc</span> <span class='hs-varid'>q</span> <span class='hs-conid'>Nothing</span><span class='hs-layout'>)</span> <span class='hs-varid'>q</span>
<a name="line-626"></a><span class='hs-comment'>{- -- Disable superfluous error checking.
<a name="line-627"></a> -- @submap'@ would replace the first argument to @lookupBy_@
<a name="line-628"></a> where
<a name="line-629"></a> submap' Nothing Empty = errorEmptyAfterNothing "submap"
<a name="line-630"></a> submap' Nothing (Arc _ _ _) = errorArcAfterNothing "submap"
<a name="line-631"></a> submap' mx t = Arc q mx t
<a name="line-632"></a>
<a name="line-633"></a>errorInvariantBroken :: String -> String -> a
<a name="line-634"></a>{-# NOINLINE errorInvariantBroken #-}
<a name="line-635"></a>errorInvariantBroken s e = error (s ++ ": Invariant was broken" ++ e')
<a name="line-636"></a> where
<a name="line-637"></a> e' = if Prelude.null e then e else ", found: " ++ e
<a name="line-638"></a>
<a name="line-639"></a>errorArcAfterNothing :: String -> a
<a name="line-640"></a>{-# NOINLINE errorArcAfterNothing #-}
<a name="line-641"></a>errorArcAfterNothing s = errorInvariantBroken s "Arc after Nothing"
<a name="line-642"></a>
<a name="line-643"></a>errorEmptyAfterNothing :: String -> a
<a name="line-644"></a>{-# NOINLINE errorEmptyAfterNothing #-}
<a name="line-645"></a>errorEmptyAfterNothing s = errorInvariantBroken s "Empty after Nothing"
<a name="line-646"></a>-- -}</span>
<a name="line-647"></a>
<a name="line-648"></a>
<a name="line-649"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-650"></a>-- Single-value modification functions (recurse and clone spine)
<a name="line-651"></a>---------------------------------------------------------------}</span>
<a name="line-652"></a>
<a name="line-653"></a><a name="alterBy"></a><span class='hs-comment'>-- TODO: We should CPS on Empty to avoid cloning spine if no change.</span>
<a name="line-654"></a><span class='hs-comment'>-- Difficulties arise with the calls to 'branch' and 'arc'. Will</span>
<a name="line-655"></a><span class='hs-comment'>-- have to create a continuation chain, so no savings on memory</span>
<a name="line-656"></a><span class='hs-comment'>-- allocation; but would have savings on held memory, if they're</span>
<a name="line-657"></a><span class='hs-comment'>-- still holding the old one...</span>
<a name="line-658"></a><span class='hs-comment'>--</span>
<a name="line-659"></a><span class='hs-comment'>-- | Generic function to alter a trie by one element with a function</span>
<a name="line-660"></a><span class='hs-comment'>-- to resolve conflicts (or non-conflicts).</span>
<a name="line-661"></a><span class='hs-definition'>alterBy</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-662"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span>
<a name="line-663"></a><span class='hs-definition'>alterBy</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>alterBy_</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>k</span> <span class='hs-varid'>v</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>k</span> <span class='hs-varid'>v</span> <span class='hs-varid'>mv</span><span class='hs-layout'>,</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-664"></a><span class='hs-comment'>-- TODO: use GHC's 'inline' function so that this gets specialized away.</span>
<a name="line-665"></a><span class='hs-comment'>-- TODO: benchmark to be sure that this doesn't introduce unforseen performance costs because of the uncurrying etc.</span>
<a name="line-666"></a>
<a name="line-667"></a>
<a name="line-668"></a><a name="alterBy_"></a><span class='hs-comment'>-- | A variant of 'alterBy' which also allows modifying the sub-trie. </span>
<a name="line-669"></a><span class='hs-definition'>alterBy_</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-670"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span>
<a name="line-671"></a><span class='hs-definition'>alterBy_</span> <span class='hs-varid'>f_</span> <span class='hs-varid'>q_</span> <span class='hs-varid'>x_</span>
<a name="line-672"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>q_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>alterEpsilon</span>
<a name="line-673"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>q_</span>
<a name="line-674"></a> <span class='hs-keyword'>where</span>
<a name="line-675"></a> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f_</span> <span class='hs-varid'>q_</span> <span class='hs-varid'>x_</span>
<a name="line-676"></a> <span class='hs-varid'>nothing</span> <span class='hs-varid'>q</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>uncurry</span> <span class='hs-layout'>(</span><span class='hs-varid'>arc</span> <span class='hs-varid'>q</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-conid'>Nothing</span> <span class='hs-conid'>Empty</span><span class='hs-layout'>)</span>
<a name="line-677"></a>
<a name="line-678"></a> <span class='hs-varid'>alterEpsilon</span> <span class='hs-varid'>t_</span><span class='hs-keyglyph'>@</span><span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>uncurry</span> <span class='hs-layout'>(</span><span class='hs-varid'>arc</span> <span class='hs-varid'>q_</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t_</span><span class='hs-layout'>)</span>
<a name="line-679"></a> <span class='hs-varid'>alterEpsilon</span> <span class='hs-varid'>t_</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>uncurry</span> <span class='hs-layout'>(</span><span class='hs-varid'>arc</span> <span class='hs-varid'>q_</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t_</span><span class='hs-layout'>)</span>
<a name="line-680"></a> <span class='hs-varid'>alterEpsilon</span> <span class='hs-varid'>t_</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>uncurry</span> <span class='hs-layout'>(</span><span class='hs-varid'>arc</span> <span class='hs-varid'>q_</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-681"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>uncurry</span> <span class='hs-layout'>(</span><span class='hs-varid'>arc</span> <span class='hs-varid'>q_</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t_</span><span class='hs-layout'>)</span>
<a name="line-682"></a>
<a name="line-683"></a>
<a name="line-684"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>nothing</span> <span class='hs-varid'>q</span>
<a name="line-685"></a>
<a name="line-686"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>t</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-687"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>nomatch</span> <span class='hs-varid'>qh</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branchMerge</span> <span class='hs-varid'>p</span> <span class='hs-varid'>t</span> <span class='hs-varid'>qh</span> <span class='hs-layout'>(</span><span class='hs-varid'>nothing</span> <span class='hs-varid'>q</span><span class='hs-layout'>)</span>
<a name="line-688"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>zero</span> <span class='hs-varid'>qh</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span>
<a name="line-689"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-690"></a> <span class='hs-keyword'>where</span>
<a name="line-691"></a> <span class='hs-varid'>qh</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>errorLogHead</span> <span class='hs-str'>"alterBy"</span> <span class='hs-varid'>q</span>
<a name="line-692"></a>
<a name="line-693"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>t_</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-694"></a> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span><span class='hs-layout'>,</span><span class='hs-varid'>k'</span><span class='hs-layout'>,</span><span class='hs-varid'>q'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>breakMaximalPrefix</span> <span class='hs-varid'>k</span> <span class='hs-varid'>q</span> <span class='hs-keyword'>in</span>
<a name="line-695"></a> <span class='hs-keyword'>case</span> <span class='hs-layout'>(</span><span class='hs-varid'>not</span> <span class='hs-varop'>$</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k'</span><span class='hs-layout'>,</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>q'</span><span class='hs-layout'>)</span> <span class='hs-keyword'>of</span>
<a name="line-696"></a> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-comment'>-- add node to middle of arc</span>
<a name="line-697"></a> <span class='hs-varid'>uncurry</span> <span class='hs-layout'>(</span><span class='hs-varid'>arc</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k'</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-698"></a> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-conid'>False</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span>
<a name="line-699"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>nothing</span> <span class='hs-varid'>q'</span> <span class='hs-keyword'>of</span>
<a name="line-700"></a> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>t_</span> <span class='hs-comment'>-- Nothing to add, reuse old arc</span>
<a name="line-701"></a> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>arc'</span> <span class='hs-layout'>(</span><span class='hs-varid'>branchMerge</span> <span class='hs-layout'>(</span><span class='hs-varid'>getPrefix</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-varid'>getPrefix</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-702"></a> <span class='hs-keyword'>where</span>
<a name="line-703"></a> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k'</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span>
<a name="line-704"></a>
<a name="line-705"></a> <span class='hs-comment'>-- inlined version of 'arc'</span>
<a name="line-706"></a> <span class='hs-varid'>arc'</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>id</span>
<a name="line-707"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>p</span> <span class='hs-conid'>Nothing</span>
<a name="line-708"></a>
<a name="line-709"></a> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span> <span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>uncurry</span> <span class='hs-layout'>(</span><span class='hs-varid'>arc</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-710"></a> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span> <span class='hs-conid'>False</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q'</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-711"></a>
<a name="line-712"></a>
<a name="line-713"></a><a name="adjustBy"></a><span class='hs-comment'>-- | Alter the value associated with a given key. If the key is not</span>
<a name="line-714"></a><span class='hs-comment'>-- present, then the trie is returned unaltered. See 'alterBy' if</span>
<a name="line-715"></a><span class='hs-comment'>-- you are interested in inserting new keys or deleting old keys.</span>
<a name="line-716"></a><span class='hs-comment'>-- Because this function does not need to worry about changing the</span>
<a name="line-717"></a><span class='hs-comment'>-- trie structure, it is somewhat faster than 'alterBy'.</span>
<a name="line-718"></a><span class='hs-definition'>adjustBy</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-719"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span>
<a name="line-720"></a><span class='hs-definition'>adjustBy</span> <span class='hs-varid'>f_</span> <span class='hs-varid'>q_</span> <span class='hs-varid'>x_</span>
<a name="line-721"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>q_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>adjustEpsilon</span>
<a name="line-722"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>q_</span>
<a name="line-723"></a> <span class='hs-keyword'>where</span>
<a name="line-724"></a> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f_</span> <span class='hs-varid'>q_</span> <span class='hs-varid'>x_</span>
<a name="line-725"></a>
<a name="line-726"></a> <span class='hs-varid'>adjustEpsilon</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span>
<a name="line-727"></a> <span class='hs-varid'>adjustEpsilon</span> <span class='hs-varid'>t_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t_</span>
<a name="line-728"></a>
<a name="line-729"></a> <span class='hs-varid'>go</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Empty</span>
<a name="line-730"></a>
<a name="line-731"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>t</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-732"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>nomatch</span> <span class='hs-varid'>qh</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t</span>
<a name="line-733"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>zero</span> <span class='hs-varid'>qh</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span>
<a name="line-734"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-735"></a> <span class='hs-keyword'>where</span>
<a name="line-736"></a> <span class='hs-varid'>qh</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>errorLogHead</span> <span class='hs-str'>"adjustBy"</span> <span class='hs-varid'>q</span>
<a name="line-737"></a>
<a name="line-738"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>t_</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-739"></a> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span><span class='hs-varid'>k'</span><span class='hs-layout'>,</span><span class='hs-varid'>q'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>breakMaximalPrefix</span> <span class='hs-varid'>k</span> <span class='hs-varid'>q</span> <span class='hs-keyword'>in</span>
<a name="line-740"></a> <span class='hs-keyword'>case</span> <span class='hs-layout'>(</span><span class='hs-varid'>not</span> <span class='hs-varop'>$</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k'</span><span class='hs-layout'>,</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>q'</span><span class='hs-layout'>)</span> <span class='hs-keyword'>of</span>
<a name="line-741"></a> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>t_</span> <span class='hs-comment'>-- don't break arc inline</span>
<a name="line-742"></a> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-conid'>False</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>t_</span> <span class='hs-comment'>-- don't break arc branching</span>
<a name="line-743"></a> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span> <span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-varid'>liftM</span> <span class='hs-varid'>f</span> <span class='hs-varid'>mv</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span>
<a name="line-744"></a> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span> <span class='hs-conid'>False</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q'</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-745"></a>
<a name="line-746"></a>
<a name="line-747"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-748"></a>-- Trie-combining functions
<a name="line-749"></a>---------------------------------------------------------------}</span>
<a name="line-750"></a>
<a name="line-751"></a><a name="mergeBy"></a><span class='hs-comment'>-- TEST CASES: foldr (unionL . uncurry singleton) empty t</span>
<a name="line-752"></a><span class='hs-comment'>-- foldr (uncurry insert) empty t</span>
<a name="line-753"></a><span class='hs-comment'>-- where t = map (\s -> (pk s, 0))</span>
<a name="line-754"></a><span class='hs-comment'>-- ["heat","hello","hoi","apple","appa","hell","appb","appc"]</span>
<a name="line-755"></a><span class='hs-comment'>--</span>
<a name="line-756"></a><span class='hs-comment'>-- | Combine two tries, using a function to resolve collisions.</span>
<a name="line-757"></a><span class='hs-comment'>-- This can only define the space of functions between union and</span>
<a name="line-758"></a><span class='hs-comment'>-- symmetric difference but, with those two, all set operations can</span>
<a name="line-759"></a><span class='hs-comment'>-- be defined (albeit inefficiently).</span>
<a name="line-760"></a><span class='hs-definition'>mergeBy</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span>
<a name="line-761"></a><span class='hs-definition'>mergeBy</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mergeBy'</span>
<a name="line-762"></a> <span class='hs-keyword'>where</span>
<a name="line-763"></a> <span class='hs-comment'>-- | Deals with epsilon entries, before recursing into @go@</span>
<a name="line-764"></a> <span class='hs-varid'>mergeBy'</span>
<a name="line-765"></a> <span class='hs-varid'>t0_</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k0</span> <span class='hs-varid'>mv0</span> <span class='hs-varid'>t0</span><span class='hs-layout'>)</span>
<a name="line-766"></a> <span class='hs-varid'>t1_</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k1</span> <span class='hs-varid'>mv1</span> <span class='hs-varid'>t1</span><span class='hs-layout'>)</span>
<a name="line-767"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k0</span> <span class='hs-varop'>&&</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k0</span> <span class='hs-layout'>(</span><span class='hs-varid'>mergeMaybe</span> <span class='hs-varid'>f</span> <span class='hs-varid'>mv0</span> <span class='hs-varid'>mv1</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t0</span> <span class='hs-varid'>t1</span><span class='hs-layout'>)</span>
<a name="line-768"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k0</span> <span class='hs-varid'>mv0</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t0</span> <span class='hs-varid'>t1_</span><span class='hs-layout'>)</span>
<a name="line-769"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k1</span> <span class='hs-varid'>mv1</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t1</span> <span class='hs-varid'>t0_</span><span class='hs-layout'>)</span>
<a name="line-770"></a> <span class='hs-varid'>mergeBy'</span>
<a name="line-771"></a> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k0</span> <span class='hs-varid'>mv0</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-varid'>t0</span><span class='hs-layout'>)</span>
<a name="line-772"></a> <span class='hs-varid'>t1_</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span>
<a name="line-773"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k0</span> <span class='hs-varid'>mv0</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t0</span> <span class='hs-varid'>t1_</span><span class='hs-layout'>)</span>
<a name="line-774"></a> <span class='hs-varid'>mergeBy'</span>
<a name="line-775"></a> <span class='hs-varid'>t0_</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span>
<a name="line-776"></a> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k1</span> <span class='hs-varid'>mv1</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-varid'>t1</span><span class='hs-layout'>)</span>
<a name="line-777"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k1</span> <span class='hs-varid'>mv1</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t1</span> <span class='hs-varid'>t0_</span><span class='hs-layout'>)</span>
<a name="line-778"></a> <span class='hs-varid'>mergeBy'</span> <span class='hs-varid'>t0_</span> <span class='hs-varid'>t1_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>t0_</span> <span class='hs-varid'>t1_</span>
<a name="line-779"></a>
<a name="line-780"></a>
<a name="line-781"></a> <span class='hs-comment'>-- | The main recursion</span>
<a name="line-782"></a> <span class='hs-varid'>go</span> <span class='hs-conid'>Empty</span> <span class='hs-varid'>t1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t1</span>
<a name="line-783"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>t0</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>t0</span>
<a name="line-784"></a>
<a name="line-785"></a> <span class='hs-comment'>-- /O(n+m)/ for this part where /n/ and /m/ are sizes of the branchings</span>
<a name="line-786"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>t0</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m0</span> <span class='hs-varid'>l0</span> <span class='hs-varid'>r0</span><span class='hs-layout'>)</span>
<a name="line-787"></a> <span class='hs-varid'>t1</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>m1</span> <span class='hs-varid'>l1</span> <span class='hs-varid'>r1</span><span class='hs-layout'>)</span>
<a name="line-788"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>shorter</span> <span class='hs-varid'>m0</span> <span class='hs-varid'>m1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>union0</span>
<a name="line-789"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>shorter</span> <span class='hs-varid'>m1</span> <span class='hs-varid'>m0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>union1</span>
<a name="line-790"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>p0</span> <span class='hs-varop'>==</span> <span class='hs-varid'>p1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m0</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>l0</span> <span class='hs-varid'>l1</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>r0</span> <span class='hs-varid'>r1</span><span class='hs-layout'>)</span>
<a name="line-791"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branchMerge</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>t0</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>t1</span>
<a name="line-792"></a> <span class='hs-keyword'>where</span>
<a name="line-793"></a> <span class='hs-varid'>union0</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>nomatch</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branchMerge</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>t0</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>t1</span>
<a name="line-794"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>zero</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>m0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m0</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>l0</span> <span class='hs-varid'>t1</span><span class='hs-layout'>)</span> <span class='hs-varid'>r0</span>
<a name="line-795"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m0</span> <span class='hs-varid'>l0</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>r0</span> <span class='hs-varid'>t1</span><span class='hs-layout'>)</span>
<a name="line-796"></a>
<a name="line-797"></a> <span class='hs-varid'>union1</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>nomatch</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>m1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branchMerge</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>t0</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>t1</span>
<a name="line-798"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>zero</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>m1</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t0</span> <span class='hs-varid'>l1</span><span class='hs-layout'>)</span> <span class='hs-varid'>r1</span>
<a name="line-799"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>m1</span> <span class='hs-varid'>l1</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t0</span> <span class='hs-varid'>r1</span><span class='hs-layout'>)</span>
<a name="line-800"></a>
<a name="line-801"></a> <span class='hs-comment'>-- We combine these branches of 'go' in order to clarify where the definitions of 'p0', 'p1', 'm'', 'p'' are relevant. However, this may introduce inefficiency in the pattern matching automaton...</span>
<a name="line-802"></a> <span class='hs-comment'>-- TODO: check. And get rid of 'go'' if it does.</span>
<a name="line-803"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>t0_</span> <span class='hs-varid'>t1_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go'</span> <span class='hs-varid'>t0_</span> <span class='hs-varid'>t1_</span>
<a name="line-804"></a> <span class='hs-keyword'>where</span>
<a name="line-805"></a> <span class='hs-varid'>p0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>getPrefix</span> <span class='hs-varid'>t0_</span>
<a name="line-806"></a> <span class='hs-varid'>p1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>getPrefix</span> <span class='hs-varid'>t1_</span>
<a name="line-807"></a> <span class='hs-varid'>m'</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branchMask</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>p1</span>
<a name="line-808"></a> <span class='hs-varid'>p'</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mask</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m'</span>
<a name="line-809"></a>
<a name="line-810"></a> <span class='hs-varid'>go'</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k0</span> <span class='hs-varid'>mv0</span> <span class='hs-varid'>t0</span><span class='hs-layout'>)</span>
<a name="line-811"></a> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k1</span> <span class='hs-varid'>mv1</span> <span class='hs-varid'>t1</span><span class='hs-layout'>)</span>
<a name="line-812"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>m'</span> <span class='hs-varop'>==</span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span>
<a name="line-813"></a> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>pre</span><span class='hs-layout'>,</span><span class='hs-varid'>k0'</span><span class='hs-layout'>,</span><span class='hs-varid'>k1'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>breakMaximalPrefix</span> <span class='hs-varid'>k0</span> <span class='hs-varid'>k1</span> <span class='hs-keyword'>in</span>
<a name="line-814"></a> <span class='hs-keyword'>if</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>pre</span>
<a name="line-815"></a> <span class='hs-keyword'>then</span> <span class='hs-varid'>error</span> <span class='hs-str'>"mergeBy: no mask, but no prefix string"</span>
<a name="line-816"></a> <span class='hs-keyword'>else</span> <span class='hs-keyword'>let</span> <span class='hs-comment'>{-# INLINE arcMerge #-}</span>
<a name="line-817"></a> <span class='hs-varid'>arcMerge</span> <span class='hs-varid'>mv'</span> <span class='hs-varid'>t1'</span> <span class='hs-varid'>t2'</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>pre</span> <span class='hs-varid'>mv'</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t1'</span> <span class='hs-varid'>t2'</span><span class='hs-layout'>)</span>
<a name="line-818"></a> <span class='hs-keyword'>in</span> <span class='hs-keyword'>case</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k0'</span><span class='hs-layout'>,</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>k1'</span><span class='hs-layout'>)</span> <span class='hs-keyword'>of</span>
<a name="line-819"></a> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>arcMerge</span> <span class='hs-layout'>(</span><span class='hs-varid'>mergeMaybe</span> <span class='hs-varid'>f</span> <span class='hs-varid'>mv0</span> <span class='hs-varid'>mv1</span><span class='hs-layout'>)</span> <span class='hs-varid'>t0</span> <span class='hs-varid'>t1</span>
<a name="line-820"></a> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-conid'>False</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>arcMerge</span> <span class='hs-varid'>mv0</span> <span class='hs-varid'>t0</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k1'</span> <span class='hs-varid'>mv1</span> <span class='hs-varid'>t1</span><span class='hs-layout'>)</span>
<a name="line-821"></a> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span><span class='hs-conid'>True</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>arcMerge</span> <span class='hs-varid'>mv1</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k0'</span> <span class='hs-varid'>mv0</span> <span class='hs-varid'>t0</span><span class='hs-layout'>)</span> <span class='hs-varid'>t1</span>
<a name="line-822"></a> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span><span class='hs-conid'>False</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>arcMerge</span> <span class='hs-conid'>Nothing</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k0'</span> <span class='hs-varid'>mv0</span> <span class='hs-varid'>t0</span><span class='hs-layout'>)</span>
<a name="line-823"></a> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k1'</span> <span class='hs-varid'>mv1</span> <span class='hs-varid'>t1</span><span class='hs-layout'>)</span>
<a name="line-824"></a> <span class='hs-varid'>go'</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span>
<a name="line-825"></a> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-sel'>_p1</span> <span class='hs-varid'>m1</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-826"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>nomatch</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>m1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branchMerge</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>t1_</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>t0_</span>
<a name="line-827"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>zero</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m1</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>m1</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t0_</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span>
<a name="line-828"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>m1</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>t0_</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-829"></a> <span class='hs-varid'>go'</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-sel'>_p0</span> <span class='hs-varid'>m0</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-830"></a> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span>
<a name="line-831"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>nomatch</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branchMerge</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>t0_</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>t1_</span>
<a name="line-832"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>zero</span> <span class='hs-varid'>p1</span> <span class='hs-varid'>m0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m0</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>l</span> <span class='hs-varid'>t1_</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span>
<a name="line-833"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m0</span> <span class='hs-varid'>l</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>r</span> <span class='hs-varid'>t1_</span><span class='hs-layout'>)</span>
<a name="line-834"></a>
<a name="line-835"></a> <span class='hs-comment'>-- Inlined branchMerge. Both tries are disjoint @Arc@s now.</span>
<a name="line-836"></a> <span class='hs-varid'>go'</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>zero</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>m'</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>p'</span> <span class='hs-varid'>m'</span> <span class='hs-varid'>t0_</span> <span class='hs-varid'>t1_</span>
<a name="line-837"></a> <span class='hs-varid'>go'</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Branch</span> <span class='hs-varid'>p'</span> <span class='hs-varid'>m'</span> <span class='hs-varid'>t1_</span> <span class='hs-varid'>t0_</span>
<a name="line-838"></a>
<a name="line-839"></a>
<a name="line-840"></a><a name="mergeMaybe"></a><span class='hs-definition'>mergeMaybe</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span>
<a name="line-841"></a><span class='hs-comment'>{-# INLINE mergeMaybe #-}</span>
<a name="line-842"></a><span class='hs-definition'>mergeMaybe</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Nothing</span> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-843"></a><span class='hs-definition'>mergeMaybe</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>mv1</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mv1</span>
<a name="line-844"></a><span class='hs-definition'>mergeMaybe</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>mv0</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mv0</span>
<a name="line-845"></a><span class='hs-definition'>mergeMaybe</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v0</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v1</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>f</span> <span class='hs-varid'>v0</span> <span class='hs-varid'>v1</span>
<a name="line-846"></a>
<a name="line-847"></a>
<a name="line-848"></a><span class='hs-comment'>{---------------------------------------------------------------
<a name="line-849"></a>-- Priority-queue functions
<a name="line-850"></a>---------------------------------------------------------------}</span>
<a name="line-851"></a>
<a name="line-852"></a><a name="minAssoc"></a><span class='hs-definition'>minAssoc</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-853"></a><span class='hs-definition'>minAssoc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>empty</span>
<a name="line-854"></a> <span class='hs-keyword'>where</span>
<a name="line-855"></a> <span class='hs-varid'>go</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-856"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span><span class='hs-layout'>,</span><span class='hs-varid'>v</span><span class='hs-layout'>)</span>
<a name="line-857"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span>
<a name="line-858"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>l</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>l</span>
<a name="line-859"></a>
<a name="line-860"></a>
<a name="line-861"></a><a name="maxAssoc"></a><span class='hs-definition'>maxAssoc</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-862"></a><span class='hs-definition'>maxAssoc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>empty</span>
<a name="line-863"></a> <span class='hs-keyword'>where</span>
<a name="line-864"></a> <span class='hs-varid'>go</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-865"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-conid'>Empty</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span><span class='hs-layout'>,</span><span class='hs-varid'>v</span><span class='hs-layout'>)</span>
<a name="line-866"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span>
<a name="line-867"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>r</span>
<a name="line-868"></a>
<a name="line-869"></a>
<a name="line-870"></a><a name="mapView"></a><span class='hs-definition'>mapView</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-871"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-872"></a><span class='hs-definition'>mapView</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-873"></a><span class='hs-definition'>mapView</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span><span class='hs-layout'>,</span><span class='hs-varid'>v</span><span class='hs-layout'>,</span><span class='hs-varid'>t</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>k</span><span class='hs-layout'>,</span><span class='hs-varid'>v</span><span class='hs-layout'>,</span> <span class='hs-varid'>f</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-874"></a>
<a name="line-875"></a>
<a name="line-876"></a><a name="updateMinViewBy"></a><span class='hs-definition'>updateMinViewBy</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-877"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-878"></a><span class='hs-definition'>updateMinViewBy</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>empty</span>
<a name="line-879"></a> <span class='hs-keyword'>where</span>
<a name="line-880"></a> <span class='hs-varid'>go</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-881"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>q'</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span>
<a name="line-882"></a> <span class='hs-keyword'>in</span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>q'</span><span class='hs-layout'>,</span><span class='hs-varid'>v</span><span class='hs-layout'>,</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>q'</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-883"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mapView</span> <span class='hs-layout'>(</span><span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-conid'>Nothing</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-884"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mapView</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span><span class='hs-varid'>l'</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l'</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span>
<a name="line-885"></a>
<a name="line-886"></a>
<a name="line-887"></a><a name="updateMaxViewBy"></a><span class='hs-definition'>updateMaxViewBy</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-888"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-layout'>(</span><span class='hs-conid'>ByteString</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Trie</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-889"></a><span class='hs-definition'>updateMaxViewBy</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>go</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>empty</span>
<a name="line-890"></a> <span class='hs-keyword'>where</span>
<a name="line-891"></a> <span class='hs-varid'>go</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>Empty</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-892"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-conid'>Empty</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>let</span> <span class='hs-varid'>q'</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span>
<a name="line-893"></a> <span class='hs-keyword'>in</span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>q'</span><span class='hs-layout'>,</span><span class='hs-varid'>v</span><span class='hs-layout'>,</span> <span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>q'</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-conid'>Empty</span><span class='hs-layout'>)</span>
<a name="line-894"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mapView</span> <span class='hs-layout'>(</span><span class='hs-varid'>arc</span> <span class='hs-varid'>k</span> <span class='hs-varid'>mv</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>append</span> <span class='hs-varid'>q</span> <span class='hs-varid'>k</span><span class='hs-layout'>)</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span>
<a name="line-895"></a> <span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-layout'>(</span><span class='hs-conid'>Branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mapView</span> <span class='hs-layout'>(</span><span class='hs-varid'>branch</span> <span class='hs-varid'>p</span> <span class='hs-varid'>m</span> <span class='hs-varid'>l</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>go</span> <span class='hs-varid'>q</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-896"></a>
<a name="line-897"></a><span class='hs-comment'>----------------------------------------------------------------</span>
<a name="line-898"></a><span class='hs-comment'>----------------------------------------------------------- fin.</span>
</pre></body>
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