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<title>src/Darcs/Patch/Prim/V3/Commute.hs</title>
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<pre><a name="line-1"></a><span class='hs-comment'>{-# OPTIONS_GHC -fno-warn-orphans #-}</span>
<a name="line-2"></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'>Prim</span><span class='hs-varop'>.</span><span class='hs-conid'>V3</span><span class='hs-varop'>.</span><span class='hs-conid'>Commute</span>
<a name="line-3"></a> <span class='hs-layout'>(</span> <span class='hs-conid'>CommuteMonad</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span> <span class='hs-layout'>)</span>
<a name="line-4"></a> <span class='hs-keyword'>where</span>
<a name="line-5"></a>
<a name="line-6"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>List</span> <span class='hs-layout'>(</span> <span class='hs-varid'>intersect</span> <span class='hs-layout'>)</span>
<a name="line-7"></a>
<a name="line-8"></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'>BS</span> <span class='hs-layout'>(</span><span class='hs-varid'>length</span><span class='hs-layout'>)</span>
<a name="line-9"></a>
<a name="line-10"></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-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>
<a name="line-11"></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'>Unsafe</span> <span class='hs-layout'>(</span> <span class='hs-varid'>unsafeCoerceP</span> <span class='hs-layout'>)</span>
<a name="line-12"></a><span class='hs-keyword'>import</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'>Prim</span><span class='hs-varop'>.</span><span class='hs-conid'>V3</span><span class='hs-varop'>.</span><span class='hs-conid'>Core</span> <span class='hs-layout'>(</span> <span class='hs-conid'>Prim</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'>Hunk</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>touches</span> <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'>Patch</span><span class='hs-varop'>.</span><span class='hs-conid'>Commute</span> <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-14"></a><span class='hs-keyword'>import</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'>Permutations</span> <span class='hs-conid'>()</span> <span class='hs-comment'>-- for Invert instance of FL</span>
<a name="line-15"></a>
<a name="line-16"></a><span class='hs-cpp'>#include "impossible.h"</span>
<a name="line-17"></a><span class='hs-cpp'>#include "gadts.h"</span>
<a name="line-18"></a>
<a name="line-19"></a><a name="CommuteMonad"></a><span class='hs-keyword'>class</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>CommuteMonad</span> <span class='hs-varid'>m</span> <span class='hs-keyword'>where</span>
<a name="line-20"></a> <span class='hs-varid'>commuteFail</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>m</span> <span class='hs-varid'>a</span>
<a name="line-21"></a> <span class='hs-comment'>-- TODO we eventually have to get rid of runCommute with this signature,</span>
<a name="line-22"></a> <span class='hs-comment'>-- since m might involve IO at some point, which we can't "run";</span>
<a name="line-23"></a> <span class='hs-comment'>-- alternatively, for IO it could always yield Nothing, having a separate</span>
<a name="line-24"></a> <span class='hs-comment'>-- IO-specific function to "run" commutes in IO</span>
<a name="line-25"></a>
<a name="line-26"></a><a name="instance%20CommuteMonad%20Maybe"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>CommuteMonad</span> <span class='hs-conid'>Maybe</span> <span class='hs-keyword'>where</span>
<a name="line-27"></a> <span class='hs-varid'>commuteFail</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-28"></a>
<a name="line-29"></a><a name="instance%20Commute%20Prim"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Commute</span> <span class='hs-conid'>Prim</span> <span class='hs-keyword'>where</span>
<a name="line-30"></a> <span class='hs-varid'>commute</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>commute'</span>
<a name="line-31"></a>
<a name="line-32"></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-33"></a> <span class='hs-varid'>commute'</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>CommuteMonad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</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-varid'>wX</span> <span class='hs-varid'>wY</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'>p</span><span class='hs-layout'>)</span> <span class='hs-varid'>wX</span> <span class='hs-varid'>wY</span><span class='hs-layout'>)</span>
<a name="line-34"></a>
<a name="line-35"></a><a name="typematch"></a><span class='hs-definition'>typematch</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Prim</span> <span class='hs-varid'>wX</span> <span class='hs-varid'>wY</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Prim</span> <span class='hs-varid'>wY</span> <span class='hs-varid'>wZ</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span>
<a name="line-36"></a><span class='hs-definition'>typematch</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>True</span> <span class='hs-comment'>-- TODO</span>
<a name="line-37"></a>
<a name="line-38"></a><a name="instance%20Commute'%20Prim"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Commute'</span> <span class='hs-conid'>Prim</span> <span class='hs-keyword'>where</span>
<a name="line-39"></a> <span class='hs-varid'>commute'</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-conop'>:></span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>null</span> <span class='hs-layout'>(</span><span class='hs-varid'>touches</span> <span class='hs-varid'>a</span> <span class='hs-varop'>`intersect`</span> <span class='hs-varid'>touches</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>unsafeCoerceP</span> <span class='hs-varid'>b</span> <span class='hs-conop'>:></span> <span class='hs-varid'>unsafeCoerceP</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-40"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>not</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-varop'>`typematch`</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>commuteFail</span>
<a name="line-41"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>commuteOverlapping</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span> <span class='hs-conop'>:></span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-42"></a>
<a name="line-43"></a><a name="commuteOverlapping"></a><span class='hs-comment'>-- Commute patches that have actual overlap in terms of touched objects, and their types allow </span>
<a name="line-44"></a><span class='hs-definition'>commuteOverlapping</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>CommuteMonad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-conid'>Prim</span> <span class='hs-conop'>:></span> <span class='hs-conid'>Prim</span><span class='hs-layout'>)</span> <span class='hs-varid'>wX</span> <span class='hs-varid'>wY</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-conid'>Prim</span> <span class='hs-conop'>:></span> <span class='hs-conid'>Prim</span><span class='hs-layout'>)</span> <span class='hs-varid'>wX</span> <span class='hs-varid'>wY</span><span class='hs-layout'>)</span>
<a name="line-45"></a><span class='hs-definition'>commuteOverlapping</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-conid'>BinaryHunk</span> <span class='hs-varid'>a</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-conop'>:></span> <span class='hs-layout'>(</span><span class='hs-conid'>BinaryHunk</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-46"></a> <span class='hs-keyword'>do</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> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>commuteHunk</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>
<a name="line-47"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>unsafeCoerceP</span> <span class='hs-layout'>(</span><span class='hs-conid'>BinaryHunk</span> <span class='hs-varid'>a</span> <span class='hs-varid'>y'</span> <span class='hs-conop'>:></span> <span class='hs-conid'>BinaryHunk</span> <span class='hs-varid'>a</span> <span class='hs-varid'>x'</span><span class='hs-layout'>)</span>
<a name="line-48"></a><span class='hs-definition'>commuteOverlapping</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-conid'>TextHunk</span> <span class='hs-varid'>a</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-conop'>:></span> <span class='hs-layout'>(</span><span class='hs-conid'>TextHunk</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-49"></a> <span class='hs-keyword'>do</span> <span class='hs-layout'>(</span><span class='hs-varid'>y'</span> <span class='hs-conop'>:></span> <span class='hs-varid'>x'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>commuteHunk</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-conop'>:></span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span>
<a name="line-50"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>unsafeCoerceP</span> <span class='hs-layout'>(</span><span class='hs-conid'>TextHunk</span> <span class='hs-varid'>a</span> <span class='hs-varid'>y'</span> <span class='hs-conop'>:></span> <span class='hs-conid'>TextHunk</span> <span class='hs-varid'>a</span> <span class='hs-varid'>x'</span><span class='hs-layout'>)</span>
<a name="line-51"></a><span class='hs-definition'>commuteOverlapping</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>commuteFail</span>
<a name="line-52"></a>
<a name="line-53"></a><a name="commuteHunk"></a><span class='hs-definition'>commuteHunk</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>CommuteMonad</span> <span class='hs-varid'>m</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-conid'>Hunk</span> <span class='hs-conop'>:></span> <span class='hs-conid'>Hunk</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-conid'>Hunk</span> <span class='hs-conop'>:></span> <span class='hs-conid'>Hunk</span><span class='hs-layout'>)</span> <span class='hs-conid'>C</span><span class='hs-layout'>(</span><span class='hs-varid'>y</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-54"></a><span class='hs-definition'>commuteHunk</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-conid'>Hunk</span> <span class='hs-varid'>off1</span> <span class='hs-varid'>old1</span> <span class='hs-varid'>new1</span><span class='hs-layout'>)</span> <span class='hs-conop'>:></span> <span class='hs-layout'>(</span><span class='hs-conid'>Hunk</span> <span class='hs-varid'>off2</span> <span class='hs-varid'>old2</span> <span class='hs-varid'>new2</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-55"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>off1</span> <span class='hs-varop'>+</span> <span class='hs-varid'>lengthnew1</span> <span class='hs-varop'><</span> <span class='hs-varid'>off2</span> <span class='hs-keyglyph'>=</span>
<a name="line-56"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Hunk</span> <span class='hs-layout'>(</span><span class='hs-varid'>off2</span> <span class='hs-comment'>-</span> <span class='hs-varid'>lengthnew1</span> <span class='hs-varop'>+</span> <span class='hs-varid'>lengthold1</span><span class='hs-layout'>)</span> <span class='hs-varid'>old2</span> <span class='hs-varid'>new2</span> <span class='hs-conop'>:></span> <span class='hs-conid'>Hunk</span> <span class='hs-varid'>off1</span> <span class='hs-varid'>old1</span> <span class='hs-varid'>new1</span>
<a name="line-57"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>off2</span> <span class='hs-varop'>+</span> <span class='hs-varid'>lengthold2</span> <span class='hs-varop'><</span> <span class='hs-varid'>off1</span> <span class='hs-keyglyph'>=</span>
<a name="line-58"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-layout'>(</span><span class='hs-conid'>Hunk</span> <span class='hs-varid'>off2</span> <span class='hs-varid'>old2</span> <span class='hs-varid'>new2</span><span class='hs-layout'>)</span> <span class='hs-conop'>:></span> <span class='hs-conid'>Hunk</span> <span class='hs-layout'>(</span><span class='hs-varid'>off1</span> <span class='hs-varop'>+</span> <span class='hs-varid'>lengthnew2</span> <span class='hs-comment'>-</span> <span class='hs-varid'>lengthold2</span><span class='hs-layout'>)</span> <span class='hs-varid'>old1</span> <span class='hs-varid'>new1</span>
<a name="line-59"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>off1</span> <span class='hs-varop'>+</span> <span class='hs-varid'>lengthnew1</span> <span class='hs-varop'>==</span> <span class='hs-varid'>off2</span> <span class='hs-varop'>&&</span>
<a name="line-60"></a> <span class='hs-varid'>lengthold2</span> <span class='hs-varop'>/=</span> <span class='hs-num'>0</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>lengthold1</span> <span class='hs-varop'>/=</span> <span class='hs-num'>0</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>lengthnew2</span> <span class='hs-varop'>/=</span> <span class='hs-num'>0</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>lengthnew1</span> <span class='hs-varop'>/=</span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span>
<a name="line-61"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Hunk</span> <span class='hs-layout'>(</span><span class='hs-varid'>off2</span> <span class='hs-comment'>-</span> <span class='hs-varid'>lengthnew1</span> <span class='hs-varop'>+</span> <span class='hs-varid'>lengthold1</span><span class='hs-layout'>)</span> <span class='hs-varid'>old2</span> <span class='hs-varid'>new2</span> <span class='hs-conop'>:></span> <span class='hs-conid'>Hunk</span> <span class='hs-varid'>off1</span> <span class='hs-varid'>old1</span> <span class='hs-varid'>new1</span>
<a name="line-62"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>off2</span> <span class='hs-varop'>+</span> <span class='hs-varid'>lengthold2</span> <span class='hs-varop'>==</span> <span class='hs-varid'>off1</span> <span class='hs-varop'>&&</span>
<a name="line-63"></a> <span class='hs-varid'>lengthold2</span> <span class='hs-varop'>/=</span> <span class='hs-num'>0</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>lengthold1</span> <span class='hs-varop'>/=</span> <span class='hs-num'>0</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>lengthnew2</span> <span class='hs-varop'>/=</span> <span class='hs-num'>0</span> <span class='hs-varop'>&&</span> <span class='hs-varid'>lengthnew1</span> <span class='hs-varop'>/=</span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span>
<a name="line-64"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Hunk</span> <span class='hs-varid'>off2</span> <span class='hs-varid'>old2</span> <span class='hs-varid'>new2</span> <span class='hs-conop'>:></span> <span class='hs-conid'>Hunk</span> <span class='hs-layout'>(</span><span class='hs-varid'>off1</span> <span class='hs-varop'>+</span> <span class='hs-varid'>lengthnew2</span> <span class='hs-comment'>-</span> <span class='hs-varid'>lengthold2</span><span class='hs-layout'>)</span> <span class='hs-varid'>old1</span> <span class='hs-varid'>new1</span>
<a name="line-65"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>commuteFail</span>
<a name="line-66"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>lengthnew1</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>BS</span><span class='hs-varop'>.</span><span class='hs-varid'>length</span> <span class='hs-varid'>new1</span>
<a name="line-67"></a> <span class='hs-varid'>lengthnew2</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>BS</span><span class='hs-varop'>.</span><span class='hs-varid'>length</span> <span class='hs-varid'>new2</span>
<a name="line-68"></a> <span class='hs-varid'>lengthold1</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>BS</span><span class='hs-varop'>.</span><span class='hs-varid'>length</span> <span class='hs-varid'>old1</span>
<a name="line-69"></a> <span class='hs-varid'>lengthold2</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>BS</span><span class='hs-varop'>.</span><span class='hs-varid'>length</span> <span class='hs-varid'>old2</span>
<a name="line-70"></a><span class='hs-definition'>commuteHunk</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>impossible</span>
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