342 lines
No EOL
19 KiB
HTML
342 lines
No EOL
19 KiB
HTML
<?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 xmlns="http://www.w3.org/1999/xhtml" lang="fr" xml:lang="fr">
|
||
<head>
|
||
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
|
||
|
||
|
||
<meta name="keywords" content="zsh, map, foldr, filter, functional, programming, higher order functions">
|
||
|
||
<link rel="shortcut icon" type="image/x-icon" href="/Scratch/img/favicon.ico" />
|
||
<link rel="stylesheet" type="text/css" href="/Scratch/assets/css/main.css" />
|
||
<link rel="stylesheet" type="text/css" href="/Scratch/css/twilight.css" />
|
||
<link rel="stylesheet" type="text/css" href="/Scratch/css/idc.css" />
|
||
<link rel="alternate" type="application/rss+xml" title="RSS" href="http://feeds.feedburner.com/yannespositocomfr"/>
|
||
|
||
<link rel="alternate" lang="fr" xml:lang="fr" title="Fonctions d'ordre supérieur en zsh" type="text/html" hreflang="fr" href="/Scratch/fr/blog/Higher-order-function-in-zsh/" />
|
||
<link rel="alternate" lang="en" xml:lang="en" title="Higher order function in zsh" type="text/html" hreflang="en" href="/Scratch/en/blog/Higher-order-function-in-zsh/" />
|
||
<script type="text/javascript" src="/Scratch/js/jquery-1.3.1.min.js"></script>
|
||
<script type="text/javascript" src="/Scratch/js/jquery.cookie.js"></script>
|
||
<script type="text/javascript" src="/Scratch/js/index.js"></script>
|
||
<!--[if lt IE 9]>
|
||
<script src="http://ie7-js.googlecode.com/svn/version/2.1(beta4)/IE9.js"></script>
|
||
<![endif]-->
|
||
<title>Fonctions d'ordre supérieur en zsh</title>
|
||
</head>
|
||
<body lang="fr" class="article">
|
||
<script type="text/javascript">// <![CDATA[
|
||
document.write('<div id="blackpage"><img src="/Scratch/img/loading.gif" alt="Chargement en cours..."/></div>');
|
||
// ]]>
|
||
</script>
|
||
|
||
<div id="content">
|
||
|
||
<div id="choix">
|
||
<div class="return"><a href="#entete">↓ Menu ↓</a></div>
|
||
<div id="choixlang">
|
||
<a href="/Scratch/en/blog/Higher-order-function-in-zsh/" onclick="setLanguage('en')">in English</a>
|
||
</div>
|
||
<div class="flush"></div>
|
||
</div>
|
||
<div id="titre">
|
||
<h1>
|
||
Fonctions d'ordre supérieur en zsh
|
||
</h1>
|
||
|
||
</div>
|
||
<div class="flush"></div>
|
||
|
||
|
||
|
||
|
||
|
||
<div class="flush"></div>
|
||
<div id="afterheader">
|
||
<div class="corps">
|
||
<p><img alt="Title image" src="/Scratch/img/blog/Higher-order-function-in-zsh/main.jpg" /></p>
|
||
|
||
|
||
<div class="intro">
|
||
|
||
|
||
<p><span class="sc"><abbr title="Trop long à lire">tlàl</abbr> : </span> des fonctions d’ordres supérieurs en zsh.</p>
|
||
|
||
|
||
</div>
|
||
|
||
|
||
<p>Tout d’abord, pourquoi c’est important d’avoir ces fonctions.
|
||
Plus je programmais avec zsh plus j’essayais d’avoir un style fonctionnel.</p>
|
||
|
||
<p>Le minimum pour pouvoir avoir du code plus lisible c’est de posséder les fonctions <code>map</code>, <code>filter</code> et <code>fold</code>.</p>
|
||
|
||
<p>Voici pourquoi avec une comparaison.
|
||
Commençons par un programme qui converti tous les gif en png dans plusieurs répertoires projets contenant tous des répertoires resources.
|
||
Avant :</p>
|
||
|
||
<p>Avant ⇒</p>
|
||
|
||
<pre class="twilight">
|
||
<span class="Comment"><span class="Comment">#</span> for each directory in projects dir</span>
|
||
<span class="Keyword">for</span> toProject <span class="Keyword">in</span> /path/to/projects/*(/N)<span class="Keyword">;</span> <span class="Keyword">do</span>
|
||
<span class="Comment"><span class="Comment">#</span> toProject is /path/to/projects/foo</span>
|
||
<span class="Comment"><span class="Comment">#</span> project become foo (:t for tail)</span>
|
||
project=<span class="Variable"><span class="Variable">${</span>toProject:t<span class="Variable">}</span></span>
|
||
<span class="Keyword">for</span> toResource <span class="Keyword">in</span> <span class="Variable"><span class="Variable">$</span>toProject</span>/resources/*.gif(.N)<span class="Keyword">;</span> <span class="Keyword">do</span>
|
||
convert <span class="Variable"><span class="Variable">$</span>toResource</span> <span class="Variable"><span class="Variable">${</span>toResource:r<span class="Variable">}</span></span>.png <span class="Keyword">&&</span> \
|
||
<span class="Constant">\r</span>m -f <span class="Variable"><span class="Variable">$</span>toResource</span>
|
||
<span class="Keyword">done</span>
|
||
<span class="Keyword">done</span>
|
||
</pre>
|
||
|
||
<ul>
|
||
<li>Le <code>(/N)</code> permet de sélectionner seulement les répertoires sans casser la boucle s’il n’y a pas de “match”.</li>
|
||
<li>Le <code>(.N)</code> permet de sélection seulement les fichiers, aussi sans tout arréter s’il ne trouve rien.</li>
|
||
<li>Le <code>:t</code> signfie “tail” ; si <code>toto=/path/to/file.ext</code> alors <code>${toto:t}=file.ext</code>.</li>
|
||
</ul>
|
||
|
||
<p>Après</p>
|
||
|
||
<pre class="twilight">
|
||
<span class="Entity">gif_to_png</span>() { convert <span class="Variable"><span class="Variable">$</span>1</span> <span class="Variable"><span class="Variable">${</span>1:r<span class="Variable">}</span></span>.png <span class="Keyword">&&</span> <span class="Constant">\r</span>m -f <span class="Variable"><span class="Variable">$</span>1</span> }
|
||
|
||
<span class="Entity">handle_resources</span>() { map gif_to_png <span class="Variable"><span class="Variable">$</span>1</span>/resources/*.gif(.N) }
|
||
|
||
map handle_resources /path/to/projects/*(/N)
|
||
</pre>
|
||
|
||
<p>Plus de bloc !
|
||
Oui, c’est un poil plus difficile à lire pour les non initiés.
|
||
Mais c’est à la fois plus concis et plus robuste.</p>
|
||
|
||
<p>Et encore ce code ne possède pas de test.
|
||
Recommençons sur le même principe.</p>
|
||
|
||
<p>Trouver les fichiers des projets qui ne contiennent pas de s dans leur nom qui ont le même nom que leur projet.</p>
|
||
|
||
<p>Before ⇒</p>
|
||
|
||
<pre class="twilight">
|
||
<span class="Keyword">for</span> toProject <span class="Keyword">in</span> Projects/*<span class="Keyword">;</span> <span class="Keyword">do</span>
|
||
project=<span class="Variable"><span class="Variable">$</span>toProject</span>:t
|
||
<span class="Keyword">if</span> print -- project <span class="Keyword">|</span> grep -v s <span class="Keyword">></span>/dev/null
|
||
<span class="Keyword">then</span>
|
||
print <span class="Variable"><span class="Variable">$</span>project</span>
|
||
<span class="Keyword">for</span> toResource <span class="Keyword">in</span> <span class="Variable"><span class="Variable">$</span>toProject</span>/*(.N)<span class="Keyword">;</span> <span class="Keyword">do</span>
|
||
<span class="Keyword">if</span> print -- <span class="Variable"><span class="Variable">${</span>toResource:t<span class="Variable">}</span></span> <span class="Keyword">|</span> grep <span class="Variable"><span class="Variable">$</span>project</span> <span class="Keyword">></span>/dev/null<span class="Keyword">;</span> <span class="Keyword">then</span>
|
||
print -- <span class="String"><span class="String">"</span>X <span class="StringVariable"><span class="StringVariable">$</span>toResource</span><span class="String">"</span></span>
|
||
<span class="Keyword">fi</span>
|
||
<span class="Keyword">done</span>
|
||
<span class="Keyword">fi</span>
|
||
<span class="Keyword">done</span>
|
||
</pre>
|
||
|
||
<p>After ⇒</p>
|
||
|
||
<pre class="twilight">
|
||
<span class="Entity">contain_no_s</span>() { print <span class="Variable"><span class="Variable">$</span>1</span> <span class="Keyword">|</span> grep -v s }
|
||
|
||
function verify_file_name {
|
||
local project=<span class="Variable"><span class="Variable">$</span>1</span>:t
|
||
<span class="Entity">contains_project_name</span>() { print <span class="Variable"><span class="Variable">$</span>1</span>:t <span class="Keyword">|</span> grep <span class="Variable"><span class="Variable">$</span>project</span> }
|
||
map <span class="String"><span class="String">"</span>print -- X<span class="String">"</span></span> <span class="String"><span class="String">$(</span>filter contains_project_name <span class="StringVariable"><span class="StringVariable">$</span>1</span>/*<span class="String"><span class="String">(</span>.N<span class="String">)</span></span><span class="String">)</span></span>
|
||
}
|
||
|
||
map verify_file_name <span class="String"><span class="String">$(</span> filter contain_no_s Projects/* <span class="String">)</span></span>
|
||
</pre>
|
||
|
||
<p>La première version peu paraître plus facile à lire.
|
||
Mais la seconde est plus bien supérieure en terme d’architecture.
|
||
Je ne veux pas discuster ici pourquoi c’est mieux.
|
||
Je vous demande simplement de me croire quand je dis que l’approche fonctionnelle est supérieure.</p>
|
||
|
||
<p>Actuellement il me manque une fonction lambda, si quelqu’un à une idée elle serait la bienvenue.
|
||
Je ne sais pas encore comment créer facilement des fonctions anonymes.</p>
|
||
|
||
<p>Voici le code source :</p>
|
||
|
||
<div class="code"><div class="file"><a href="/Scratch/fr/blog/Higher-order-function-in-zsh/code/functional.sh"> ➥ functional.sh </a></div><div class="withfile">
|
||
<pre class="twilight">
|
||
<span class="Comment"><span class="Comment">#</span>!/usr/bin/env zsh</span>
|
||
|
||
<span class="Comment"><span class="Comment">#</span> Provide higer-order functions </span>
|
||
|
||
<span class="Comment"><span class="Comment">#</span> usage:</span>
|
||
<span class="Comment"><span class="Comment">#</span></span>
|
||
<span class="Comment"><span class="Comment">#</span> $ foo(){print "x: $1"}</span>
|
||
<span class="Comment"><span class="Comment">#</span> $ map foo a b c d</span>
|
||
<span class="Comment"><span class="Comment">#</span> x: a</span>
|
||
<span class="Comment"><span class="Comment">#</span> x: b</span>
|
||
<span class="Comment"><span class="Comment">#</span> x: c</span>
|
||
<span class="Comment"><span class="Comment">#</span> x: d</span>
|
||
function map {
|
||
local func_name=<span class="Variable"><span class="Variable">$</span>1</span>
|
||
shift
|
||
<span class="Keyword">for</span> elem <span class="Keyword">in</span> <span class="Variable"><span class="Variable">$</span>@</span><span class="Keyword">;</span> print -- <span class="String"><span class="String">$(</span>eval <span class="StringVariable"><span class="StringVariable">$</span>func_name</span> <span class="StringVariable"><span class="StringVariable">$</span>elem</span><span class="String">)</span></span>
|
||
}
|
||
|
||
<span class="Comment"><span class="Comment">#</span> $ bar() { print $(($1 + $2)) }</span>
|
||
<span class="Comment"><span class="Comment">#</span> $ fold bar 0 1 2 3 4 5</span>
|
||
<span class="Comment"><span class="Comment">#</span> 15</span>
|
||
<span class="Comment"><span class="Comment">#</span> -- but also</span>
|
||
<span class="Comment"><span class="Comment">#</span> $ fold bar 0 $( seq 1 100 )</span>
|
||
function fold {
|
||
<span class="Keyword">if</span> ((<span class="Variable"><span class="Variable">$</span>#</span><span class="Keyword"><</span>2)) {
|
||
print -- <span class="String"><span class="String">"</span>ERROR fold use at least 2 arguments<span class="String">"</span></span> <span class="Keyword">>&2</span>
|
||
return 1
|
||
}
|
||
<span class="Keyword">if</span> ((<span class="Variable"><span class="Variable">$</span>#</span><span class="Keyword"><</span>3)) {
|
||
print -- <span class="Variable"><span class="Variable">$</span>2</span>
|
||
return 0
|
||
} <span class="Keyword">else</span> {
|
||
local acc
|
||
local right
|
||
local func_name=<span class="Variable"><span class="Variable">$</span>1</span>
|
||
local init_value=<span class="Variable"><span class="Variable">$</span>2</span>
|
||
local first_value=<span class="Variable"><span class="Variable">$</span>3</span>
|
||
shift 3
|
||
right=<span class="String"><span class="String">$(</span> fold <span class="StringVariable"><span class="StringVariable">$</span>func_name</span> <span class="StringVariable"><span class="StringVariable">$</span>init_value</span> <span class="StringVariable"><span class="StringVariable">$</span>@</span> <span class="String">)</span></span>
|
||
acc=<span class="String"><span class="String">$(</span> eval <span class="String"><span class="String">"</span><span class="StringVariable"><span class="StringVariable">$</span>func_name</span> <span class="StringVariable"><span class="StringVariable">$</span>first_value</span> <span class="StringVariable"><span class="StringVariable">$</span>right</span><span class="String">"</span></span> <span class="String">)</span></span>
|
||
print -- <span class="Variable"><span class="Variable">$</span>acc</span>
|
||
return 0
|
||
}
|
||
}
|
||
|
||
<span class="Comment"><span class="Comment">#</span> usage:</span>
|
||
<span class="Comment"><span class="Comment">#</span></span>
|
||
<span class="Comment"><span class="Comment">#</span> $ baz() { print $1 | grep baz }</span>
|
||
<span class="Comment"><span class="Comment">#</span> $ filter baz titi bazaar biz</span>
|
||
<span class="Comment"><span class="Comment">#</span> bazaar</span>
|
||
function filter {
|
||
local predicate=<span class="Variable"><span class="Variable">$</span>1</span>
|
||
local result
|
||
typeset -a result
|
||
shift
|
||
<span class="Keyword">for</span> elem <span class="Keyword">in</span> <span class="Variable"><span class="Variable">$</span>@</span><span class="Keyword">;</span> <span class="Keyword">do</span>
|
||
<span class="Keyword">if</span> eval <span class="Variable"><span class="Variable">$</span>predicate</span> <span class="Variable"><span class="Variable">$</span>elem</span> <span class="Keyword">></span>/dev/null<span class="Keyword">;</span> <span class="Keyword">then</span>
|
||
result=( <span class="Variable"><span class="Variable">$</span>result</span> <span class="Variable"><span class="Variable">$</span>elem</span> )
|
||
<span class="Keyword">fi</span>
|
||
<span class="Keyword">done</span>
|
||
print <span class="Variable"><span class="Variable">$</span>result</span>
|
||
}
|
||
</pre>
|
||
</div></div>
|
||
|
||
</div>
|
||
|
||
|
||
|
||
<div id="choixrss">
|
||
<a id="rss" href="http://feeds.feedburner.com/yannespositocomfr">
|
||
s'abonner
|
||
</a>
|
||
</div>
|
||
<script type="text/javascript">
|
||
$(document).ready(function(){
|
||
$('#comment').hide();
|
||
$('#clickcomment').click(showComments);
|
||
});
|
||
function showComments() {
|
||
$('#comment').show();
|
||
$('#clickcomment').fadeOut();
|
||
}
|
||
document.write('<div id="clickcomment">Commentaires</div>');
|
||
</script>
|
||
<div class="flush"></div>
|
||
<div class="corps" id="comment">
|
||
<h2 class="first">commentaires</h2>
|
||
<noscript>
|
||
Vous devez activer javascript pour commenter.
|
||
</noscript>
|
||
|
||
<script type="text/javascript">
|
||
var idcomments_acct = 'a307f0044511ff1b5cfca573fc0a52e7';
|
||
var idcomments_post_id = '/Scratch/fr/blog/Higher-order-function-in-zsh/';
|
||
var idcomments_post_url = 'http://yannesposito.com/Scratch/fr/blog/Higher-order-function-in-zsh/';
|
||
</script>
|
||
<span id="IDCommentsPostTitle" style="display:none"></span>
|
||
<script type='text/javascript' src='/Scratch/js/genericCommentWrapperV2.js'></script>
|
||
|
||
</div>
|
||
|
||
<div id="entete" class="corps_spaced">
|
||
<div id="liens">
|
||
<ul><li><a href="/Scratch/fr/">Bienvenue</a></li>
|
||
<li><a href="/Scratch/fr/blog/">Blog</a></li>
|
||
<li><a href="/Scratch/fr/softwares/">Softwares</a></li>
|
||
<li><a href="/Scratch/fr/about/">À propos</a></li></ul>
|
||
</div>
|
||
<div class="flush"></div>
|
||
<hr/>
|
||
<div id="next_before_articles">
|
||
<div id="previous_articles">
|
||
articles précédents
|
||
|
||
<div class="previous_article">
|
||
<a href="/Scratch/fr/blog/programming-language-experience/"><span class="nicer">«</span> Mon expérience avec les languages de programmation</a>
|
||
</div>
|
||
|
||
|
||
<div class="previous_article">
|
||
<a href="/Scratch/fr/blog/Learn-Vim-Progressively/"><span class="nicer">«</span> Apprenez Vim Progressivement</a>
|
||
</div>
|
||
|
||
|
||
<div class="previous_article">
|
||
<a href="/Scratch/fr/blog/A-more-convenient-diff/"><span class="nicer">«</span> Un diff plus pratique</a>
|
||
</div>
|
||
|
||
|
||
</div>
|
||
<div id="next_articles">
|
||
articles suivants
|
||
|
||
<div class="next_article">
|
||
<a href="/Scratch/fr/blog/Yesod-excellent-ideas/">Les idées de yesod <span class="nicer">»</span></a>
|
||
</div>
|
||
|
||
|
||
<div class="next_article">
|
||
<a href="/Scratch/fr/blog/SVG-and-m4-fractals/">Accroître le pouvoir des languages déficients. <span class="nicer">»</span></a>
|
||
</div>
|
||
|
||
|
||
<div class="next_article">
|
||
<a href="/Scratch/fr/blog/Yesod-tutorial-for-newbies/">Site en Haskell <span class="nicer">»</span></a>
|
||
</div>
|
||
|
||
|
||
</div>
|
||
<div class="flush"></div>
|
||
</div>
|
||
</div>
|
||
|
||
|
||
<div id="bottom">
|
||
<div>
|
||
<a rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/deed.fr">Droits de reproduction ©, Yann Esposito</a>
|
||
</div>
|
||
<div id="lastmod">
|
||
Écrit le : 28/09/2011
|
||
modifié le : 26/10/2011
|
||
</div>
|
||
<div>
|
||
Site entièrement réalisé avec
|
||
<a href="http://www.vim.org">Vim</a>
|
||
et
|
||
<a href="http://nanoc.stoneship.org">nanoc</a>
|
||
</div>
|
||
<div>
|
||
<a href="/Scratch/fr/validation/">Validation</a>
|
||
<a href="http://validator.w3.org/check?uri=referer"> [xhtml] </a>
|
||
.
|
||
<a href="http://jigsaw.w3.org/css-validator/check/referer?profile=css3"> [css] </a>
|
||
.
|
||
<a href="http://validator.w3.org/feed/check.cgi?url=http%3A//yannesposito.com/Scratch/fr/blog/feed/feed.xml">[rss]</a>
|
||
</div>
|
||
</div>
|
||
<div class="clear"></div>
|
||
</div>
|
||
</body>
|
||
</html> |