<?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>Language/Preprocessor/Cpphs/ReadFirst.hs</title> <link type='text/css' rel='stylesheet' href='hscolour.css' /> </head> <body> <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 : ReadFirst</span> <a name="line-4"></a><span class='hs-comment'>-- Copyright : 2004 Malcolm Wallace</span> <a name="line-5"></a><span class='hs-comment'>-- Licence : LGPL</span> <a name="line-6"></a><span class='hs-comment'>-- </span> <a name="line-7"></a><span class='hs-comment'>-- Maintainer : Malcolm Wallace <Malcolm.Wallace@cs.york.ac.uk></span> <a name="line-8"></a><span class='hs-comment'>-- Stability : experimental</span> <a name="line-9"></a><span class='hs-comment'>-- Portability : All</span> <a name="line-10"></a><span class='hs-comment'>--</span> <a name="line-11"></a><span class='hs-comment'>-- Read the first file that matches in a list of search paths.</span> <a name="line-12"></a><span class='hs-comment'>-----------------------------------------------------------------------------</span> <a name="line-13"></a> <a name="line-14"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Language</span><span class='hs-varop'>.</span><span class='hs-conid'>Preprocessor</span><span class='hs-varop'>.</span><span class='hs-conid'>Cpphs</span><span class='hs-varop'>.</span><span class='hs-conid'>ReadFirst</span> <a name="line-15"></a> <span class='hs-layout'>(</span> <span class='hs-varid'>readFirst</span> <a name="line-16"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <a name="line-17"></a> <a name="line-18"></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'>hPutStrLn</span><span class='hs-layout'>,</span> <span class='hs-varid'>stderr</span><span class='hs-layout'>)</span> <a name="line-19"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>Directory</span> <span class='hs-layout'>(</span><span class='hs-varid'>doesFileExist</span><span class='hs-layout'>)</span> <a name="line-20"></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'>intersperse</span><span class='hs-layout'>)</span> <a name="line-21"></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'>when</span><span class='hs-layout'>)</span> <a name="line-22"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Language</span><span class='hs-varop'>.</span><span class='hs-conid'>Preprocessor</span><span class='hs-varop'>.</span><span class='hs-conid'>Cpphs</span><span class='hs-varop'>.</span><span class='hs-conid'>Position</span> <span class='hs-layout'>(</span><span class='hs-conid'>Posn</span><span class='hs-layout'>,</span><span class='hs-varid'>directory</span><span class='hs-layout'>)</span> <a name="line-23"></a> <a name="line-24"></a><a name="readFirst"></a><span class='hs-comment'>-- | Attempt to read the given file from any location within the search path.</span> <a name="line-25"></a><span class='hs-comment'>-- The first location found is returned, together with the file content.</span> <a name="line-26"></a><span class='hs-comment'>-- (The directory of the calling file is always searched first, then</span> <a name="line-27"></a><span class='hs-comment'>-- the current directory, finally any specified search path.)</span> <a name="line-28"></a><span class='hs-definition'>readFirst</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-comment'>-- ^ filename</span> <a name="line-29"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Posn</span> <span class='hs-comment'>-- ^ inclusion point</span> <a name="line-30"></a> <span class='hs-keyglyph'>-></span> <span class='hs-keyglyph'>[</span><span class='hs-conid'>String</span><span class='hs-keyglyph'>]</span> <span class='hs-comment'>-- ^ search path</span> <a name="line-31"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Bool</span> <span class='hs-comment'>-- ^ report warnings?</span> <a name="line-32"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span> <span class='hs-conid'>FilePath</span> <a name="line-33"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>String</span> <a name="line-34"></a> <span class='hs-layout'>)</span> <span class='hs-comment'>-- ^ discovered filepath, and file contents</span> <a name="line-35"></a> <a name="line-36"></a><span class='hs-definition'>readFirst</span> <span class='hs-varid'>name</span> <span class='hs-varid'>demand</span> <span class='hs-varid'>path</span> <span class='hs-varid'>warn</span> <span class='hs-keyglyph'>=</span> <a name="line-37"></a> <span class='hs-varid'>try</span> <span class='hs-layout'>(</span><span class='hs-varid'>cons</span> <span class='hs-varid'>dd</span> <span class='hs-layout'>(</span><span class='hs-str'>"."</span><span class='hs-conop'>:</span><span class='hs-varid'>path</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-38"></a> <span class='hs-keyword'>where</span> <a name="line-39"></a> <span class='hs-varid'>dd</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>directory</span> <span class='hs-varid'>demand</span> <a name="line-40"></a> <span class='hs-varid'>cons</span> <span class='hs-varid'>x</span> <span class='hs-varid'>xs</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>null</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>xs</span> <span class='hs-keyword'>else</span> <span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span> <a name="line-41"></a> <span class='hs-varid'>try</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <a name="line-42"></a> <span class='hs-varid'>when</span> <span class='hs-varid'>warn</span> <span class='hs-varop'>$</span> <a name="line-43"></a> <span class='hs-varid'>hPutStrLn</span> <span class='hs-varid'>stderr</span> <span class='hs-layout'>(</span><span class='hs-str'>"Warning: Can't find file \""</span><span class='hs-varop'>++</span><span class='hs-varid'>name</span> <a name="line-44"></a> <span class='hs-varop'>++</span><span class='hs-str'>"\" in directories\n\t"</span> <a name="line-45"></a> <span class='hs-varop'>++</span><span class='hs-varid'>concat</span> <span class='hs-layout'>(</span><span class='hs-varid'>intersperse</span> <span class='hs-str'>"\n\t"</span> <span class='hs-layout'>(</span><span class='hs-varid'>cons</span> <span class='hs-varid'>dd</span> <span class='hs-layout'>(</span><span class='hs-str'>"."</span><span class='hs-conop'>:</span><span class='hs-varid'>path</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <a name="line-46"></a> <span class='hs-varop'>++</span><span class='hs-str'>"\n Asked for by: "</span><span class='hs-varop'>++</span><span class='hs-varid'>show</span> <span class='hs-varid'>demand</span><span class='hs-layout'>)</span> <a name="line-47"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-str'>"missing file: "</span><span class='hs-varop'>++</span><span class='hs-varid'>name</span><span class='hs-layout'>,</span><span class='hs-str'>""</span><span class='hs-layout'>)</span> <a name="line-48"></a> <span class='hs-varid'>try</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-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <a name="line-49"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>file</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>p</span><span class='hs-varop'>++</span><span class='hs-chr'>'/'</span><span class='hs-conop'>:</span><span class='hs-varid'>name</span> <a name="line-50"></a> <span class='hs-varid'>ok</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>doesFileExist</span> <span class='hs-varid'>file</span> <a name="line-51"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>not</span> <span class='hs-varid'>ok</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>try</span> <span class='hs-varid'>ps</span> <a name="line-52"></a> <span class='hs-keyword'>else</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>content</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>readFile</span> <span class='hs-varid'>file</span> <a name="line-53"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>file</span><span class='hs-layout'>,</span><span class='hs-varid'>content</span><span class='hs-layout'>)</span> </pre></body> </html>
