<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html> <head> <!-- Generated by HsColour, http://code.haskell.org/~malcolm/hscolour/ --> <title>src/Darcs/Patch/Commute.hs</title> <link type='text/css' rel='stylesheet' href='hscolour.css' /> </head> <body> <pre><a name="line-1"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Darcs</span><span class='hs-varop'>.</span><span class='hs-conid'>Patch</span><span class='hs-varop'>.</span><span class='hs-conid'>Commute</span> <a name="line-2"></a> <span class='hs-layout'>(</span> <span class='hs-conid'>Commute</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <a name="line-3"></a> <span class='hs-varid'>commuteFL</span><span class='hs-layout'>,</span> <span class='hs-varid'>commuteFLorComplain</span><span class='hs-layout'>,</span> <a name="line-4"></a> <span class='hs-varid'>commuteRL</span><span class='hs-layout'>,</span> <span class='hs-varid'>commuteRLFL</span><span class='hs-layout'>,</span> <a name="line-5"></a> <span class='hs-varid'>toFwdCommute</span><span class='hs-layout'>,</span> <span class='hs-varid'>toRevCommute</span> <a name="line-6"></a> <span class='hs-layout'>)</span> <a name="line-7"></a> <span class='hs-keyword'>where</span> <a name="line-8"></a> <a name="line-9"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Darcs</span><span class='hs-varop'>.</span><span class='hs-conid'>Witnesses</span><span class='hs-varop'>.</span><span class='hs-conid'>Ordered</span> <span class='hs-layout'>(</span><span class='hs-conid'>FL</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-conid'>RL</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <a name="line-10"></a> <span class='hs-varid'>reverseFL</span><span class='hs-layout'>,</span> <span class='hs-varid'>reverseRL</span><span class='hs-layout'>,</span> <a name="line-11"></a> <span class='hs-layout'>(</span><span class='hs-conop'>:></span><span class='hs-layout'>)</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-conop'>:<</span><span class='hs-layout'>)</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span> <a name="line-12"></a> <span class='hs-layout'>)</span> <a name="line-13"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Darcs</span><span class='hs-varop'>.</span><span class='hs-conid'>Witnesses</span><span class='hs-varop'>.</span><span class='hs-conid'>Sealed</span> <span class='hs-layout'>(</span> <span class='hs-conid'>Sealed2</span><span class='hs-layout'>,</span> <span class='hs-varid'>seal2</span> <span class='hs-layout'>)</span> <a name="line-14"></a> <a name="line-15"></a><span class='hs-cpp'>#include "gadts.h"</span> <a name="line-16"></a> <a name="line-17"></a><span class='hs-comment'>-- | Things that can commute.</span> <a name="line-18"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>Commute</span> <span class='hs-varid'>p</span> <span class='hs-keyword'>where</span> <a name="line-19"></a> <span class='hs-varid'>commute</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</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-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-20"></a> <a name="line-21"></a><a name="toFwdCommute"></a><span class='hs-comment'>-- | Swaps the ordered pair type so that commute can be</span> <a name="line-22"></a><span class='hs-comment'>-- called directly.</span> <a name="line-23"></a><span class='hs-definition'>toFwdCommute</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Commute</span> <span class='hs-varid'>p</span><span class='hs-layout'>,</span> <span class='hs-conid'>Commute</span> <span class='hs-varid'>q</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <a name="line-24"></a> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-conop'>:<</span> <span class='hs-varid'>q</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>q</span> <span class='hs-conop'>:<</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-25"></a> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>q</span> <span class='hs-conop'>:></span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-varid'>q</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-26"></a><span class='hs-definition'>toFwdCommute</span> <span class='hs-varid'>c</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-conop'>:></span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>x'</span> <span class='hs-conop'>:<</span> <span class='hs-varid'>y'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>c</span> <span class='hs-layout'>(</span><span class='hs-varid'>y</span> <span class='hs-conop'>:<</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <a name="line-27"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>y'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>x'</span><span class='hs-layout'>)</span> <a name="line-28"></a> <a name="line-29"></a><a name="toRevCommute"></a><span class='hs-comment'>-- | Swaps the ordered pair type from the order expected</span> <a name="line-30"></a><span class='hs-comment'>-- by commute to the reverse order.</span> <a name="line-31"></a><span class='hs-definition'>toRevCommute</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Commute</span> <span class='hs-varid'>p</span><span class='hs-layout'>,</span> <span class='hs-conid'>Commute</span> <span class='hs-varid'>q</span><span class='hs-layout'>,</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <a name="line-32"></a> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-varid'>q</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>q</span> <span class='hs-conop'>:></span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-33"></a> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>q</span> <span class='hs-conop'>:<</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-conop'>:<</span> <span class='hs-varid'>q</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-34"></a><span class='hs-definition'>toRevCommute</span> <span class='hs-varid'>c</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-conop'>:<</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>x'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>y'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>c</span> <span class='hs-layout'>(</span><span class='hs-varid'>y</span> <span class='hs-conop'>:></span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <a name="line-35"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>y'</span> <span class='hs-conop'>:<</span> <span class='hs-varid'>x'</span><span class='hs-layout'>)</span> <a name="line-36"></a> <a name="line-37"></a> <a name="line-38"></a> <a name="line-39"></a><a name="instance%20Commute%20(FL%20p)"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Commute</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Commute</span> <span class='hs-layout'>(</span><span class='hs-conid'>FL</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <a name="line-40"></a> <span class='hs-varid'>commute</span> <span class='hs-layout'>(</span><span class='hs-conid'>NilFL</span> <span class='hs-conop'>:></span> <span class='hs-varid'>x</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'>x</span> <span class='hs-conop'>:></span> <span class='hs-conid'>NilFL</span><span class='hs-layout'>)</span> <a name="line-41"></a> <span class='hs-varid'>commute</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-conop'>:></span> <span class='hs-conid'>NilFL</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'>NilFL</span> <span class='hs-conop'>:></span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <a name="line-42"></a> <span class='hs-varid'>commute</span> <span class='hs-layout'>(</span><span class='hs-varid'>xs</span> <span class='hs-conop'>:></span> <span class='hs-varid'>ys</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>ys'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>rxs'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>commuteRLFL</span> <span class='hs-layout'>(</span><span class='hs-varid'>reverseFL</span> <span class='hs-varid'>xs</span> <span class='hs-conop'>:></span> <span class='hs-varid'>ys</span><span class='hs-layout'>)</span> <a name="line-43"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>ys'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>reverseRL</span> <span class='hs-varid'>rxs'</span> <a name="line-44"></a> <a name="line-45"></a> <a name="line-46"></a><a name="commuteRLFL"></a><span class='hs-definition'>commuteRLFL</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Commute</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-conid'>RL</span> <span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-conid'>FL</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</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-layout'>(</span><span class='hs-conid'>FL</span> <span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-conid'>RL</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-47"></a><span class='hs-definition'>commuteRLFL</span> <span class='hs-layout'>(</span><span class='hs-conid'>NilRL</span> <span class='hs-conop'>:></span> <span class='hs-varid'>ys</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'>ys</span> <span class='hs-conop'>:></span> <span class='hs-conid'>NilRL</span><span class='hs-layout'>)</span> <a name="line-48"></a><span class='hs-definition'>commuteRLFL</span> <span class='hs-layout'>(</span><span class='hs-varid'>xs</span> <span class='hs-conop'>:></span> <span class='hs-conid'>NilFL</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'>NilFL</span> <span class='hs-conop'>:></span> <span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <a name="line-49"></a><span class='hs-definition'>commuteRLFL</span> <span class='hs-layout'>(</span><span class='hs-varid'>xs</span> <span class='hs-conop'>:></span> <span class='hs-varid'>y</span> <span class='hs-conop'>:>:</span> <span class='hs-varid'>ys</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>y'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>xs'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>commuteRL</span> <span class='hs-layout'>(</span><span class='hs-varid'>xs</span> <span class='hs-conop'>:></span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <a name="line-50"></a> <span class='hs-varid'>ys'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>xs''</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>commuteRLFL</span> <span class='hs-layout'>(</span><span class='hs-varid'>xs'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>ys</span><span class='hs-layout'>)</span> <a name="line-51"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>y'</span> <span class='hs-conop'>:>:</span> <span class='hs-varid'>ys'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>xs''</span><span class='hs-layout'>)</span> <a name="line-52"></a> <a name="line-53"></a><a name="commuteRL"></a><span class='hs-definition'>commuteRL</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Commute</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-conid'>RL</span> <span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</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-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-conid'>RL</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-54"></a><span class='hs-definition'>commuteRL</span> <span class='hs-layout'>(</span><span class='hs-varid'>z</span> <span class='hs-conop'>:<:</span> <span class='hs-varid'>zs</span> <span class='hs-conop'>:></span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>w'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>z'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>commute</span> <span class='hs-layout'>(</span><span class='hs-varid'>z</span> <span class='hs-conop'>:></span> <span class='hs-varid'>w</span><span class='hs-layout'>)</span> <a name="line-55"></a> <span class='hs-varid'>w''</span> <span class='hs-conop'>:></span> <span class='hs-varid'>zs'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>commuteRL</span> <span class='hs-layout'>(</span><span class='hs-varid'>zs</span> <span class='hs-conop'>:></span> <span class='hs-varid'>w'</span><span class='hs-layout'>)</span> <a name="line-56"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>w''</span> <span class='hs-conop'>:></span> <span class='hs-varid'>z'</span> <span class='hs-conop'>:<:</span> <span class='hs-varid'>zs'</span><span class='hs-layout'>)</span> <a name="line-57"></a><span class='hs-definition'>commuteRL</span> <span class='hs-layout'>(</span><span class='hs-conid'>NilRL</span> <span class='hs-conop'>:></span> <span class='hs-varid'>w</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'>w</span> <span class='hs-conop'>:></span> <span class='hs-conid'>NilRL</span><span class='hs-layout'>)</span> <a name="line-58"></a> <a name="line-59"></a><a name="commuteFLorComplain"></a><span class='hs-definition'>commuteFLorComplain</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Commute</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-conid'>FL</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Either</span> <span class='hs-layout'>(</span><span class='hs-conid'>Sealed2</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-conid'>FL</span> <span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-60"></a><span class='hs-definition'>commuteFLorComplain</span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-conid'>NilFL</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Right</span> <span class='hs-layout'>(</span><span class='hs-conid'>NilFL</span> <span class='hs-conop'>:></span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <a name="line-61"></a><span class='hs-definition'>commuteFLorComplain</span> <span class='hs-layout'>(</span><span class='hs-varid'>q</span> <span class='hs-conop'>:></span> <span class='hs-varid'>p</span> <span class='hs-conop'>:>:</span> <span class='hs-varid'>ps</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>commute</span> <span class='hs-layout'>(</span><span class='hs-varid'>q</span> <span class='hs-conop'>:></span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-keyword'>of</span> <a name="line-62"></a> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-varid'>p'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>q'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <a name="line-63"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>commuteFLorComplain</span> <span class='hs-layout'>(</span><span class='hs-varid'>q'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>ps</span><span class='hs-layout'>)</span> <span class='hs-keyword'>of</span> <a name="line-64"></a> <span class='hs-conid'>Right</span> <span class='hs-layout'>(</span><span class='hs-varid'>ps'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>q''</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Right</span> <span class='hs-layout'>(</span><span class='hs-varid'>p'</span> <span class='hs-conop'>:>:</span> <span class='hs-varid'>ps'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>q''</span><span class='hs-layout'>)</span> <a name="line-65"></a> <span class='hs-conid'>Left</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Left</span> <span class='hs-varid'>l</span> <a name="line-66"></a> <span class='hs-conid'>Nothing</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Left</span> <span class='hs-varop'>$</span> <span class='hs-varid'>seal2</span> <span class='hs-varid'>p</span> <a name="line-67"></a> <a name="line-68"></a><a name="commuteFL"></a><span class='hs-definition'>commuteFL</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Commute</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-conid'>FL</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</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-layout'>(</span><span class='hs-conid'>FL</span> <span class='hs-varid'>p</span> <span class='hs-conop'>:></span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-69"></a><span class='hs-definition'>commuteFL</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>either</span> <span class='hs-layout'>(</span><span class='hs-varid'>const</span> <span class='hs-conid'>Nothing</span><span class='hs-layout'>)</span> <span class='hs-conid'>Just</span> <span class='hs-varop'>.</span> <span class='hs-varid'>commuteFLorComplain</span> <a name="line-70"></a> <a name="line-71"></a><a name="instance%20Commute%20(RL%20p)"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Commute</span> <span class='hs-varid'>p</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Commute</span> <span class='hs-layout'>(</span><span class='hs-conid'>RL</span> <span class='hs-varid'>p</span><span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <a name="line-72"></a> <span class='hs-varid'>commute</span> <span class='hs-layout'>(</span><span class='hs-varid'>xs</span> <span class='hs-conop'>:></span> <span class='hs-varid'>ys</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>fys'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>xs'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>commuteRLFL</span> <span class='hs-layout'>(</span><span class='hs-varid'>xs</span> <span class='hs-conop'>:></span> <span class='hs-varid'>reverseRL</span> <span class='hs-varid'>ys</span><span class='hs-layout'>)</span> <a name="line-73"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>reverseFL</span> <span class='hs-varid'>fys'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>xs'</span><span class='hs-layout'>)</span> <a name="line-74"></a> </pre></body> </html>
