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<!DOCTYPE html> <html lang="en"> <head> <title>Macro attributes - H3RALD</title> <link href='https://fonts.googleapis.com/css?family=Crimson+Text:400,400italic,600,600italic,700,700italic' rel='stylesheet' type='text/css'> <meta charset="utf-8" /> <meta name="author" content="Fabio Cevasco" /> <meta name="robots" content="all, follow" /> <meta name="Revisit-After" content="2 Days" /> <meta name="description" content="H3RALD - Fabio Cevasco's Web Site" /> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta name="keywords" content="h3rald, fabio cevasco, glyph, ruby" /> <link rel="shortcut icon" href="/favicon.png" type="image/png" /> <meta content="44.388041;9.073248" name="ICBM" /> <link rel="stylesheet" type="text/css" href="/styles/bootstrap.css" /> <link rel="stylesheet" type="text/css" href="/styles/github.css" /> <link rel="stylesheet" type="text/css" href="/styles/style.css" /> <!--[if lt IE 9]> <script src="https://html5shiv.googlecode.com/svn/trunk/html5.js"></script> <![endif]--> <script src="https://www.google.com/jsapi?key=ABQIAAAAr6RY1Z6dchG_sX9WDLSy3xRlq2n1sm52B5HDRR5tm6o8XM18FhR56xHNNH6CsX86uN5VoTrglpyOyQ" type="text/javascript"></script> <script src="/js/sevenup.js" type="text/javascript"></script> <script src="/js/sevenup_black.js" type="text/javascript"></script> <script src="https://code.jquery.com/jquery-latest.js" type="text/javascript"></script> <script src="/js/jquery-timeago.js" type="text/javascript"></script> <script src="/js/date.js" type="text/javascript"></script> <script src="/js/hyphenator.js" type="text/javascript"></script> <script src="/js/init.js" type="text/javascript"></script> <script src="/js/search.js" type="text/javascript"></script> <script src="/js/highlight.js" type="text/javascript"></script> <script src="/js/bootstrap.js" type="text/javascript"></script> </head> <body> <div class="container"> <div class="row" id="header-row"> <div class="col-md-6 main-title"> <h1> <a href="/"><img src="/img/h3rald.png" alt="H3RALD" /></a> </h1> </div> <div class="col-md-4 col-md-offset-2"> <div class="gcse-searchbox" data-enableAutoComplete="true"></div> </div> </div> <div id="search_results"> <div class="gcse-searchresults" data-linkTarget="_top"></div> </div> <div id="main-navbar" class="navbar navbar-inverse" role="navigation"> <div class="navbar-header"> <button type="button" class="navbar-toggle" data-toggle="collapse" data-target=".navbar-collapse"> <span class="sr-only">Toggle navigation</span> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span> </button> </div> <div class="navbar-collapse collapse"> <ul class="nav navbar-nav"> <li><a href="/"><i class="fa fa-home"></i> HOME</a></li> <li><a href="/projects/"><i class="fa fa-briefcase"></i> PROJECTS</a></li> <li><a href="/tags/"><i class="fa fa-tags"></i> TAGS</a></li> <li><a href="/archives/"><i class="fa fa-archive"></i> ARCHIVES</a></li> <li><a href="/about/"><i class="fa fa-question-circle"></i> ABOUT</a></li> <li><a href="/contact/"><i class="fa fa-envelope"></i> CONTACT</a></li> </ul> </div> </div> </div> <div class="container"> <article class="page"> <header class="row"> <hgroup class="col-md-9"> <h1>Macro attributes</h1> <h2>Glyph</h2> </hgroup> </header> <section id="body-text" class="hyphenate"> <nav class="navigation"><a href="/glyph/book/text_editing/macro_intro.html">← Introducing Glyph Macros</a> | <a href="/glyph/book/index.html">Contents</a> | <a href="/glyph/book/text_editing/macro_composition.html">Macro Composition →</a></nav> <p>Although a macro can take any number of parameters, they are often no more than two or three, for readibility reasons: parameters have no name, but their position within a macro is significant.</p> <p>If you have something like this:</p> <div class="CodeRay"> <div class="code"><pre><span class="line-numbers"><a href="#n1" name="n1">1</a></span>custom_image[test.png|50%|50%|Test Image]</pre></div> </div> <p>it may still be easy enough to understand what each parameter is used for, but:</p> <ul> <li>you can easily forget that the third parameter is the image width</li> <li>if you don’t want to resize the image, you still have to pass <em>empty parameters</em> to the macro, like this: <code>custom_image[test2.png|||Test Image]</code></li> </ul> <p>To avoid these situations, some macros which would normally take three or four parameters take optional attributes instead, so you can write:</p> <div class="CodeRay"> <div class="code"><pre><span class="line-numbers"><a href="#n1" name="n1">1</a></span>image[test.png <span class="line-numbers"><a href="#n2" name="n2">2</a></span> @width[50%] <span class="line-numbers"><a href="#n3" name="n3">3</a></span> @alt[Test Image] <span class="line-numbers"><a href="#n4" name="n4">4</a></span> @height[50%] <span class="line-numbers"><a href="#n5" name="n5">5</a></span>]</pre></div> </div> <p>More verbose, of course, but definitely more readable. In this way, if you won't want to scale an image, you can safely omit the <code>@width</code> and <code>@height</code> attributes.</p> <aside class="note"> <span class="note-title">Note</span>Like parameters, attributes can contain other macros, too. </aside> <nav class="navigation"><a href="/glyph/book/text_editing/macro_intro.html">← Introducing Glyph Macros</a> | <a href="/glyph/book/index.html">Contents</a> | <a href="/glyph/book/text_editing/macro_composition.html">Macro Composition →</a></nav> </section> </article> </div> <footer> <section> <p>H3RALD Web Site v8.4 © 2004 — 2014 <em>Fabio Cevasco</em></p> </section> </footer> <script type="text/javascript"> var disqus_shortname = 'h3rald'; (function() { var dsq = document.createElement('script'); dsq.type = 'text/javascript'; dsq.async = true; dsq.src = '//' + disqus_shortname + '.disqus.com/embed.js'; (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(dsq); })(); </script> <noscript>Please enable JavaScript to view the <a href="http://disqus.com/?ref_noscript">comments powered by Disqus.</a></noscript> <a href="http://disqus.com" class="dsq-brlink">comments powered by <span class="logo-disqus">Disqus</span></a> <script> hljs.tabReplace = ' '; hljs.initHighlightingOnLoad(); </script> <!-- Start Google Analytics --> <script type="text/javascript"> var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-18587377-1']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 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