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<pre><a name="line-1"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span>
<a name="line-2"></a><span class='hs-comment'>-- |</span>
<a name="line-3"></a><span class='hs-comment'>-- Module : ForSyDe.OSharing</span>
<a name="line-4"></a><span class='hs-comment'>-- Copyright : (c) SAM Group, KTH/ICT/ECS 2007-2008</span>
<a name="line-5"></a><span class='hs-comment'>-- License : BSD-style (see the file LICENSE)</span>
<a name="line-6"></a><span class='hs-comment'>-- </span>
<a name="line-7"></a><span class='hs-comment'>-- Maintainer : forsyde-dev@ict.kth.se</span>
<a name="line-8"></a><span class='hs-comment'>-- Stability : experimental</span>
<a name="line-9"></a><span class='hs-comment'>-- Portability : portable</span>
<a name="line-10"></a><span class='hs-comment'>--</span>
<a name="line-11"></a><span class='hs-comment'>-- This module provides support for Observable Sharing: <<a href="http://www.cs.chalmers.se/~koen/pubs/entry-asian99-lava.html">http://www.cs.chalmers.se/~koen/pubs/entry-asian99-lava.html</a>></span>
<a name="line-12"></a><span class='hs-comment'>-- </span>
<a name="line-13"></a><span class='hs-comment'>-- It provides:</span>
<a name="line-14"></a><span class='hs-comment'>--</span>
<a name="line-15"></a><span class='hs-comment'>-- * 'URef': Unsafe Unmutable references, using them causes side effects.</span>
<a name="line-16"></a><span class='hs-comment'>--</span>
<a name="line-17"></a><span class='hs-comment'>-- * 'URefTable': a table were 'URef's are used as key and can store</span>
<a name="line-18"></a><span class='hs-comment'>-- any value.</span>
<a name="line-19"></a><span class='hs-comment'>-- </span>
<a name="line-20"></a><span class='hs-comment'>-- /This Module was taken from Lava2000's/ @Ref.hs@ /module/:</span>
<a name="line-21"></a><span class='hs-comment'>-- <<a href="http://www.cs.chalmers.se/~koen/Lava/">http://www.cs.chalmers.se/~koen/Lava/</a>></span>
<a name="line-22"></a><span class='hs-comment'>-- </span>
<a name="line-23"></a><span class='hs-comment'>-- IMPORTANT WARNING: Even if all the functions causing side effects</span>
<a name="line-24"></a><span class='hs-comment'>-- are set as NOINLINE and that all currently known</span>
<a name="line-25"></a><span class='hs-comment'>-- Haskell compilers are based in graph reduction</span>
<a name="line-26"></a><span class='hs-comment'>-- (i.e. referential transparency will be preserved if </span>
<a name="line-27"></a><span class='hs-comment'>-- sharing is), there are other optimisations than inlining</span>
<a name="line-28"></a><span class='hs-comment'>-- that can break Observable Sharing, e.g. Common </span>
<a name="line-29"></a><span class='hs-comment'>-- Subexpression Elimination (CSE).</span>
<a name="line-30"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span>
<a name="line-31"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>ForSyDe</span><span class='hs-varop'>.</span><span class='hs-conid'>OSharing</span>
<a name="line-32"></a> <span class='hs-layout'>(</span> <span class='hs-comment'>-- Unsafe references</span>
<a name="line-33"></a> <span class='hs-conid'>URef</span><span class='hs-layout'>,</span>
<a name="line-34"></a> <span class='hs-varid'>newURef</span><span class='hs-layout'>,</span>
<a name="line-35"></a> <span class='hs-varid'>readURef</span><span class='hs-layout'>,</span>
<a name="line-36"></a> <span class='hs-comment'>-- Tables of Unsafe References (IO version)</span>
<a name="line-37"></a> <span class='hs-conid'>URefTableIO</span><span class='hs-layout'>,</span>
<a name="line-38"></a> <span class='hs-varid'>newURefTableIO</span><span class='hs-layout'>,</span>
<a name="line-39"></a> <span class='hs-varid'>addEntryIO</span><span class='hs-layout'>,</span>
<a name="line-40"></a> <span class='hs-varid'>queryIO</span><span class='hs-layout'>,</span>
<a name="line-41"></a> <span class='hs-comment'>-- Tables of Unsafe References (IO version)</span>
<a name="line-42"></a> <span class='hs-conid'>URefTableST</span><span class='hs-layout'>,</span>
<a name="line-43"></a> <span class='hs-varid'>newURefTableST</span><span class='hs-layout'>,</span>
<a name="line-44"></a> <span class='hs-varid'>addEntryST</span><span class='hs-layout'>,</span>
<a name="line-45"></a> <span class='hs-varid'>queryST</span><span class='hs-layout'>,</span>
<a name="line-46"></a> <span class='hs-comment'>-- Memoizating functions</span>
<a name="line-47"></a> <span class='hs-varid'>memoURef</span><span class='hs-layout'>,</span>
<a name="line-48"></a> <span class='hs-varid'>memoURefIO</span><span class='hs-layout'>,</span>
<a name="line-49"></a> <span class='hs-varid'>memoURefST</span><span class='hs-layout'>)</span>
<a name="line-50"></a> <span class='hs-keyword'>where</span>
<a name="line-51"></a>
<a name="line-52"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>ForSyDe</span><span class='hs-varop'>.</span><span class='hs-conid'>OSharing</span><span class='hs-varop'>.</span><span class='hs-conid'>UDynamic</span>
<a name="line-53"></a>
<a name="line-54"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-varid'>fixIO</span><span class='hs-layout'>)</span>
<a name="line-55"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>Unsafe</span> <span class='hs-layout'>(</span><span class='hs-varid'>unsafePerformIO</span><span class='hs-layout'>)</span>
<a name="line-56"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>IORef</span> <span class='hs-layout'>(</span><span class='hs-conid'>IORef</span><span class='hs-layout'>,</span> <span class='hs-varid'>newIORef</span><span class='hs-layout'>,</span> <span class='hs-varid'>readIORef</span><span class='hs-layout'>,</span> <span class='hs-varid'>writeIORef</span><span class='hs-layout'>)</span>
<a name="line-57"></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-varop'>.</span><span class='hs-conid'>ST</span>
<a name="line-58"></a>
<a name="line-59"></a>
<a name="line-60"></a>
<a name="line-61"></a><a name="URef"></a><span class='hs-comment'>-- | An Unsafe Unmutable Reference to a value of type a </span>
<a name="line-62"></a><a name="URef"></a><span class='hs-comment'>--</span>
<a name="line-63"></a><a name="URef"></a><span class='hs-comment'>-- An 'URef' is implemented as follows: it has two pieces of information. The</span>
<a name="line-64"></a><a name="URef"></a><span class='hs-comment'>-- first one is an updatable list of entries for each table it is a member in.</span>
<a name="line-65"></a><a name="URef"></a><span class='hs-comment'>-- Since the types of the Tables vary, the URef has no idea what type of</span>
<a name="line-66"></a><a name="URef"></a><span class='hs-comment'>-- values it is supposed to store. So we use dynamic types.</span>
<a name="line-67"></a><a name="URef"></a><span class='hs-comment'>--</span>
<a name="line-68"></a><a name="URef"></a><span class='hs-comment'>-- Since it is an updatable list, it is an IORef, which we also use to compare</span>
<a name="line-69"></a><a name="URef"></a><span class='hs-comment'>-- two 'URef's. The second part is just the value the URef is pointing at (this</span>
<a name="line-70"></a><a name="URef"></a><span class='hs-comment'>-- can never change anyway since references are unmutable).</span>
<a name="line-71"></a><a name="URef"></a><span class='hs-comment'>--</span>
<a name="line-72"></a><a name="URef"></a><span class='hs-comment'>-- FIXME: why IORef? it should maybe be STRef?</span>
<a name="line-73"></a><a name="URef"></a><span class='hs-comment'>-- Besides: Is it guaranteed that the values of an IORef</span>
<a name="line-74"></a><a name="URef"></a><span class='hs-comment'>-- are not changed by the garbage collector?</span>
<a name="line-75"></a><a name="URef"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>URef</span> <span class='hs-varid'>a</span>
<a name="line-76"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>URef</span> <span class='hs-layout'>(</span><span class='hs-conid'>IORef</span> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-conid'>URefTableTag</span><span class='hs-layout'>,</span> <span class='hs-conid'>UDynamic</span><span class='hs-layout'>)</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span> <span class='hs-varid'>a</span>
<a name="line-77"></a>
<a name="line-78"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Eq</span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-79"></a> <span class='hs-conid'>URef</span> <span class='hs-varid'>r1</span> <span class='hs-keyword'>_</span> <span class='hs-varop'>==</span> <span class='hs-conid'>URef</span> <span class='hs-varid'>r2</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>r1</span> <span class='hs-varop'>==</span> <span class='hs-varid'>r2</span>
<a name="line-80"></a>
<a name="line-81"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Show</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Show</span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-82"></a> <span class='hs-varid'>showsPrec</span> <span class='hs-keyword'>_</span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>showChar</span> <span class='hs-chr'>'{'</span> <span class='hs-varop'>.</span> <span class='hs-varid'>shows</span> <span class='hs-varid'>a</span> <span class='hs-varop'>.</span> <span class='hs-varid'>showChar</span> <span class='hs-chr'>'}'</span>
<a name="line-83"></a>
<a name="line-84"></a>
<a name="line-85"></a><a name="newURef"></a><span class='hs-comment'>-- | Create a new Unsafe Unmutable Reference to a Haskell object</span>
<a name="line-86"></a><span class='hs-comment'>--</span>
<a name="line-87"></a><span class='hs-comment'>-- This operation, as explained in the Observable sharing paper, can cuase</span>
<a name="line-88"></a><span class='hs-comment'>-- side-effects, since the value returned (the 'URef') is not determined by</span>
<a name="line-89"></a><span class='hs-comment'>-- the arguments of the function (i.e. different calls to 'newURef' with</span>
<a name="line-90"></a><span class='hs-comment'>-- the same argument return different 'URef's). </span>
<a name="line-91"></a><span class='hs-definition'>newURef</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>URef</span> <span class='hs-varid'>a</span>
<a name="line-92"></a><span class='hs-definition'>newURef</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafePerformIO</span> <span class='hs-varop'>$</span>
<a name="line-93"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newIORef</span> <span class='hs-conid'>[]</span>
<a name="line-94"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</span> <span class='hs-varid'>r</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-95"></a><span class='hs-comment'>{-# NOINLINE newURef #-}</span>
<a name="line-96"></a>
<a name="line-97"></a><a name="readURef"></a><span class='hs-comment'>-- | Read the value pointed by the 'URef'.</span>
<a name="line-98"></a><span class='hs-definition'>readURef</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>URef</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span>
<a name="line-99"></a><span class='hs-definition'>readURef</span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>a</span>
<a name="line-100"></a>
<a name="line-101"></a><span class='hs-comment'>--------------</span>
<a name="line-102"></a><span class='hs-comment'>-- URefTableIO </span>
<a name="line-103"></a><span class='hs-comment'>--------------</span>
<a name="line-104"></a>
<a name="line-105"></a><a name="URefTableTag"></a><span class='hs-comment'>-- | A unique identifier which univocally designates a table </span>
<a name="line-106"></a><a name="URefTableTag"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>URefTableTag</span>
<a name="line-107"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IORef</span> <span class='hs-conid'>()</span>
<a name="line-108"></a>
<a name="line-109"></a>
<a name="line-110"></a><a name="URefTableIO"></a><span class='hs-comment'>-- | A 'URefTable' a b </span>
<a name="line-111"></a><a name="URefTableIO"></a><span class='hs-comment'>-- </span>
<a name="line-112"></a><a name="URefTableIO"></a><span class='hs-comment'>-- * Unsafe References to a value of type "a" (key of the table)</span>
<a name="line-113"></a><a name="URefTableIO"></a><span class='hs-comment'>-- * Values of type "b" associated to each key</span>
<a name="line-114"></a><a name="URefTableIO"></a><span class='hs-comment'>-- </span>
<a name="line-115"></a><a name="URefTableIO"></a><span class='hs-comment'>-- Here is how we implement Tables of URefs:</span>
<a name="line-116"></a><a name="URefTableIO"></a><span class='hs-comment'>--</span>
<a name="line-117"></a><a name="URefTableIO"></a><span class='hs-comment'>-- A Table is nothing but a unique tag, of type TableTag. TableTag can be</span>
<a name="line-118"></a><a name="URefTableIO"></a><span class='hs-comment'>-- anything, as long as it is easy to create new ones, and we can compare them</span>
<a name="line-119"></a><a name="URefTableIO"></a><span class='hs-comment'>-- for equality. (I chose IORef ()).</span>
<a name="line-120"></a><a name="URefTableIO"></a><span class='hs-comment'>--</span>
<a name="line-121"></a><a name="URefTableIO"></a><span class='hs-comment'>-- So how do we store URefs in a Table? We do not want the Tables keeping</span>
<a name="line-122"></a><a name="URefTableIO"></a><span class='hs-comment'>-- track of their URefs (which would be disastrous when the table becomes big,</span>
<a name="line-123"></a><a name="URefTableIO"></a><span class='hs-comment'>-- and we would not have any garbage collection).</span>
<a name="line-124"></a><a name="URefTableIO"></a><span class='hs-comment'>--</span>
<a name="line-125"></a><a name="URefTableIO"></a><span class='hs-comment'>-- Instead, every URef keeps track of the value it has in each table it is</span>
<a name="line-126"></a><a name="URefTableIO"></a><span class='hs-comment'>-- in. This has the advantage that we have a constant lookup time (if the</span>
<a name="line-127"></a><a name="URefTableIO"></a><span class='hs-comment'>-- number of Tables we are using is small), and we get garbage collection of</span>
<a name="line-128"></a><a name="URefTableIO"></a><span class='hs-comment'>-- table entries for free.</span>
<a name="line-129"></a><a name="URefTableIO"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>URefTableIO</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span>
<a name="line-130"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>URefTableIO</span> <span class='hs-conid'>URefTableTag</span>
<a name="line-131"></a> <span class='hs-keyword'>deriving</span> <span class='hs-conid'>Eq</span>
<a name="line-132"></a>
<a name="line-133"></a><a name="newURefTableIO"></a><span class='hs-comment'>-- | Create a new table</span>
<a name="line-134"></a><span class='hs-definition'>newURefTableIO</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>URefTableIO</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-135"></a><span class='hs-definition'>newURefTableIO</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>URefTableIO</span> <span class='hs-varop'>`fmap`</span> <span class='hs-varid'>newIORef</span> <span class='hs-conid'>()</span>
<a name="line-136"></a>
<a name="line-137"></a><a name="queryIO"></a><span class='hs-comment'>-- | Query the value corresponding to an 'URef' </span>
<a name="line-138"></a><span class='hs-definition'>queryIO</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>URefTableIO</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>URef</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-139"></a><span class='hs-definition'>queryIO</span> <span class='hs-layout'>(</span><span class='hs-conid'>URefTableIO</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</span> <span class='hs-varid'>r</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-140"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>list</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>readIORef</span> <span class='hs-varid'>r</span>
<a name="line-141"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>unsafeFromUDyn</span> <span class='hs-varop'>`fmap`</span> <span class='hs-varid'>lookup</span> <span class='hs-varid'>t</span> <span class='hs-varid'>list</span><span class='hs-layout'>)</span>
<a name="line-142"></a>
<a name="line-143"></a><a name="addEntryIO"></a><span class='hs-comment'>-- | Add an ('URef' a, b) pair entry to the table </span>
<a name="line-144"></a><span class='hs-definition'>addEntryIO</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>URefTableIO</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-comment'>-- ^ key of the entry </span>
<a name="line-145"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>URef</span> <span class='hs-varid'>a</span>
<a name="line-146"></a> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-comment'>-- ^ value of the entry </span>
<a name="line-147"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-148"></a><span class='hs-definition'>addEntryIO</span> <span class='hs-layout'>(</span><span class='hs-conid'>URefTableIO</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</span> <span class='hs-varid'>r</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>=</span>
<a name="line-149"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>list</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>readIORef</span> <span class='hs-varid'>r</span>
<a name="line-150"></a> <span class='hs-varid'>writeIORef</span> <span class='hs-varid'>r</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>t</span><span class='hs-layout'>,</span> <span class='hs-varid'>unsafeToUDyn</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-conop'>:</span> <span class='hs-varid'>filter</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varop'>/=</span> <span class='hs-varid'>t</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>fst</span><span class='hs-layout'>)</span> <span class='hs-varid'>list</span><span class='hs-layout'>)</span>
<a name="line-151"></a>
<a name="line-152"></a><span class='hs-comment'>--------------</span>
<a name="line-153"></a><span class='hs-comment'>-- URefTableST</span>
<a name="line-154"></a><span class='hs-comment'>--------------</span>
<a name="line-155"></a>
<a name="line-156"></a><a name="URefTableST"></a><span class='hs-comment'>-- | 'ST' version of 'URefTableIO'</span>
<a name="line-157"></a><a name="URefTableST"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>URefTableST</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span>
<a name="line-158"></a> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>URefTableST</span> <span class='hs-layout'>(</span><span class='hs-conid'>URefTableIO</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-159"></a> <span class='hs-keyword'>deriving</span> <span class='hs-conid'>Eq</span>
<a name="line-160"></a>
<a name="line-161"></a><a name="newURefTableST"></a><span class='hs-comment'>-- | 'ST' version of 'newURefTableIO'</span>
<a name="line-162"></a><span class='hs-definition'>newURefTableST</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>ST</span> <span class='hs-varid'>s</span> <span class='hs-layout'>(</span><span class='hs-conid'>URefTableST</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-163"></a><span class='hs-definition'>newURefTableST</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafeIOToST</span> <span class='hs-layout'>(</span><span class='hs-conid'>URefTableST</span> <span class='hs-varop'>`fmap`</span> <span class='hs-varid'>newURefTableIO</span><span class='hs-layout'>)</span>
<a name="line-164"></a>
<a name="line-165"></a><a name="queryST"></a><span class='hs-comment'>-- | 'ST' version of 'queryIO'</span>
<a name="line-166"></a><span class='hs-definition'>queryST</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>URefTableST</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>URef</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ST</span> <span class='hs-varid'>s</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-167"></a><span class='hs-definition'>queryST</span> <span class='hs-layout'>(</span><span class='hs-conid'>URefTableST</span> <span class='hs-varid'>tab</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafeIOToST</span> <span class='hs-layout'>(</span><span class='hs-varid'>queryIO</span> <span class='hs-varid'>tab</span> <span class='hs-varid'>r</span><span class='hs-layout'>)</span>
<a name="line-168"></a>
<a name="line-169"></a><a name="addEntryST"></a><span class='hs-comment'>-- | 'ST' version of 'addEntryIO'</span>
<a name="line-170"></a><span class='hs-definition'>addEntryST</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>URefTableST</span> <span class='hs-varid'>s</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>URef</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-conid'>ST</span> <span class='hs-varid'>s</span> <span class='hs-conid'>()</span>
<a name="line-171"></a><span class='hs-definition'>addEntryST</span> <span class='hs-layout'>(</span><span class='hs-conid'>URefTableST</span> <span class='hs-varid'>tab</span><span class='hs-layout'>)</span> <span class='hs-varid'>r</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafeIOToST</span> <span class='hs-layout'>(</span><span class='hs-varid'>addEntryIO</span> <span class='hs-varid'>tab</span> <span class='hs-varid'>r</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-172"></a>
<a name="line-173"></a><span class='hs-comment'>--------------------------------</span>
<a name="line-174"></a><span class='hs-comment'>-- Memoization of URef functions</span>
<a name="line-175"></a><span class='hs-comment'>--------------------------------</span>
<a name="line-176"></a>
<a name="line-177"></a><a name="memoURef"></a><span class='hs-comment'>-- | Generates a memoizated version of a function taking 'URef' values </span>
<a name="line-178"></a><span class='hs-definition'>memoURef</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</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-layout'>(</span><span class='hs-conid'>URef</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-179"></a><span class='hs-definition'>memoURef</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafePerformIO</span> <span class='hs-varop'>.</span> <span class='hs-varid'>memoURefIO</span> <span class='hs-layout'>(</span><span class='hs-varid'>return</span> <span class='hs-varop'>.</span> <span class='hs-varid'>f</span><span class='hs-layout'>)</span>
<a name="line-180"></a><span class='hs-comment'>{-# NOINLINE memoURef #-}</span>
<a name="line-181"></a>
<a name="line-182"></a><a name="memoURefIO"></a><span class='hs-comment'>-- | 'IO' version of 'memoURef'</span>
<a name="line-183"></a><span class='hs-definition'>memoURefIO</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-184"></a><span class='hs-definition'>memoURefIO</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafePerformIO</span> <span class='hs-varop'>$</span>
<a name="line-185"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>tab</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newURefTableIO</span>
<a name="line-186"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>f'</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>mb</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>queryIO</span> <span class='hs-varid'>tab</span> <span class='hs-varid'>r</span>
<a name="line-187"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>mb</span> <span class='hs-keyword'>of</span>
<a name="line-188"></a> <span class='hs-conid'>Just</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span> <span class='hs-varid'>return</span> <span class='hs-varid'>b</span>
<a name="line-189"></a> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>fixIO</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span>
<a name="line-190"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>addEntryIO</span> <span class='hs-varid'>tab</span> <span class='hs-varid'>r</span> <span class='hs-varid'>b</span>
<a name="line-191"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>r</span>
<a name="line-192"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>f'</span>
<a name="line-193"></a><span class='hs-comment'>{-# NOINLINE memoURefIO #-}</span>
<a name="line-194"></a>
<a name="line-195"></a><a name="memoURefST"></a><span class='hs-comment'>-- | 'ST' version of 'memoURef'</span>
<a name="line-196"></a><span class='hs-definition'>memoURefST</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ST</span> <span class='hs-varid'>s</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>URef</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ST</span> <span class='hs-varid'>s</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-197"></a><span class='hs-definition'>memoURefST</span> <span class='hs-varid'>f</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafePerformST</span> <span class='hs-varop'>$</span>
<a name="line-198"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>tab</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newURefTableST</span>
<a name="line-199"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>f'</span> <span class='hs-varid'>r</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>mb</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>queryST</span> <span class='hs-varid'>tab</span> <span class='hs-varid'>r</span>
<a name="line-200"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>mb</span> <span class='hs-keyword'>of</span>
<a name="line-201"></a> <span class='hs-conid'>Just</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span> <span class='hs-varid'>return</span> <span class='hs-varid'>b</span>
<a name="line-202"></a> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>fixST</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span>
<a name="line-203"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>addEntryST</span> <span class='hs-varid'>tab</span> <span class='hs-varid'>r</span> <span class='hs-varid'>b</span>
<a name="line-204"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>r</span>
<a name="line-205"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>f'</span>
<a name="line-206"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>unsafePerformST</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafePerformIO</span> <span class='hs-varop'>.</span> <span class='hs-varid'>unsafeSTToIO</span>
<a name="line-207"></a><span class='hs-comment'>{-# NOINLINE memoURefST #-}</span>
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