<?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>Control/Arrow/Transformer.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 : Control.Arrow.Transformer</span> <a name="line-4"></a><span class='hs-comment'>-- Copyright : (c) Ross Paterson 2003</span> <a name="line-5"></a><span class='hs-comment'>-- License : BSD-style (see the LICENSE file in the distribution)</span> <a name="line-6"></a><span class='hs-comment'>--</span> <a name="line-7"></a><span class='hs-comment'>-- Maintainer : ross@soi.city.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 : portable</span> <a name="line-10"></a><span class='hs-comment'>--</span> <a name="line-11"></a><span class='hs-comment'>-- Arrow transformers, for making new arrow types out of old ones.</span> <a name="line-12"></a> <a name="line-13"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Arrow</span><span class='hs-varop'>.</span><span class='hs-conid'>Transformer</span> <span class='hs-layout'>(</span> <a name="line-14"></a> <span class='hs-conid'>ArrowTransformer</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span> <a name="line-15"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span> <a name="line-16"></a> <a name="line-17"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Arrow</span> <a name="line-18"></a> <a name="line-19"></a><a name="ArrowTransformer"></a><span class='hs-comment'>-- | Construct a new arrow from an existing one.</span> <a name="line-20"></a><a name="ArrowTransformer"></a><span class='hs-keyword'>class</span> <span class='hs-layout'>(</span><span class='hs-conid'>Arrow</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Arrow</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>ArrowTransformer</span> <span class='hs-varid'>f</span> <span class='hs-varid'>a</span> <span class='hs-keyword'>where</span> <a name="line-21"></a> <a name="line-22"></a> <span class='hs-comment'>-- | A transformation of arrows, preserving 'arr', '>>>' and 'first'.</span> <a name="line-23"></a> <span class='hs-comment'>--</span> <a name="line-24"></a> <span class='hs-comment'>-- Typical usage in arrow notation:</span> <a name="line-25"></a> <span class='hs-comment'>--</span> <a name="line-26"></a> <span class='hs-comment'>-- > proc p -> ...</span> <a name="line-27"></a> <span class='hs-comment'>-- > (|lift cmd|)</span> <a name="line-28"></a> <a name="line-29"></a> <span class='hs-varid'>lift</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>f</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-varid'>c</span> </pre></body> </html>