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diff --git a/articles/xerl-0.4-expression-separator/index.html b/articles/xerl-0.4-expression-separator/index.html new file mode 100644 index 00000000..a5be223f --- /dev/null +++ b/articles/xerl-0.4-expression-separator/index.html @@ -0,0 +1,211 @@ +<!DOCTYPE html> +<html lang="en"> + +<head> + <meta charset="utf-8"> + <meta name="viewport" content="width=device-width, initial-scale=1.0"> + <meta name="description" content=""> + <meta name="author" content="Loïc Hoguin based on a design from (Soft10) Pol Cámara"> + + <meta name="generator" content="Hugo 0.15" /> + + <title>Nine Nines: Xerl: expression separator</title> + + <link href='http://fonts.googleapis.com/css?family=Open+Sans:400,700,400italic' rel='stylesheet' type='text/css'> + + <link href="/css/bootstrap.min.css" rel="stylesheet"> + <link href="/css/99s.css" rel="stylesheet"> + + <link rel="shortcut icon" href="/img/ico/favicon.ico"> + <link rel="apple-touch-icon-precomposed" sizes="114x114" href="/img/ico/apple-touch-icon-114.png"> + <link rel="apple-touch-icon-precomposed" sizes="72x72" href="/img/ico/apple-touch-icon-72.png"> + <link rel="apple-touch-icon-precomposed" href="/img/ico/apple-touch-icon-57.png"> + + +</head> + + +<body class=""> + <header id="page-head"> + <div id="topbar" class="container"> + <div class="row"> + <div class="span2"> + <h1 id="logo"><a href="/" title="99s">99s</a></h1> + </div> + <div class="span10"> + + <div id="side-header"> + <nav> + <ul> + <li class="active"><a title="Hear my thoughts" href="/articles">Articles</a></li> + <li><a title="Watch my talks" href="/talks">Talks</a></li> + <li><a title="Read the docs" href="/docs">Documentation</a></li> + <li><a title="Request my services" href="/services">Consulting & Training</a></li> + </ul> + </nav> + <ul id="social"> + <li> + <a href="https://github.com/ninenines" title="Check my Github repositories"><img src="/img/ico_github.png" data-hover="/img/ico_github_alt.png" alt="Github"></a> + </li> + <li> + <a title="Keep in touch!" href="http://twitter.com/lhoguin"><img src="/img/ico_microblog.png" data-hover="/img/ico_microblog_alt.png"></a> + </li> + <li> + <a title="Contact me" href="mailto:[email protected]"><img src="/img/ico_mail.png" data-hover="/img/ico_mail_alt.png"></a> + </li> + </ul> + </div> + </div> + </div> + </div> + + +</header> + +<div id="contents"> +<div class="container"> +<div class="row"> +<div class="span9 maincol"> + +<article class="blog_item"> +<header> + <h1 class="lined-header"><span>Xerl: expression separator</span></h1> + <p class="date"> + <span class="day">01</span> + <span class="month">Mar</span> + </p> +</header> + +<div class="paragraph"><p>As promised we are adding an expression separator this time.
+This will be short and easy.</p></div>
+<div class="paragraph"><p>In the tokenizer we only need to add a line recognizing the
+comma as a valid token.</p></div>
+<div class="listingblock">
+<div class="content"><!-- Generator: GNU source-highlight 3.1.8
+by Lorenzo Bettini
+http://www.lorenzobettini.it
+http://www.gnu.org/software/src-highlite -->
+<pre><tt>, <span style="color: #990000">:</span> {<span style="color: #FF6600">token</span>, {<span style="color: #FF6600">','</span>, <span style="color: #009900">TokenLine</span>}}<span style="color: #990000">.</span></tt></pre></div></div>
+<div class="paragraph"><p>Then we need to change the following lines in the parser:</p></div>
+<div class="listingblock">
+<div class="content"><!-- Generator: GNU source-highlight 3.1.8
+by Lorenzo Bettini
+http://www.lorenzobettini.it
+http://www.gnu.org/software/src-highlite -->
+<pre><tt><span style="color: #FF6600">exprs</span> <span style="color: #990000">-></span> <span style="color: #FF6600">expr</span> <span style="color: #990000">:</span> [<span style="color: #FF6600">'$1'</span>]<span style="color: #990000">.</span>
+<span style="color: #FF6600">exprs</span> <span style="color: #990000">-></span> <span style="color: #FF6600">expr</span> <span style="color: #FF6600">exprs</span> <span style="color: #990000">:</span> [<span style="color: #FF6600">'$1'</span> | <span style="color: #FF6600">'$2'</span>]<span style="color: #990000">.</span></tt></pre></div></div>
+<div class="paragraph"><p>And add a comma between the expressions on the second line:</p></div>
+<div class="listingblock">
+<div class="content"><!-- Generator: GNU source-highlight 3.1.8
+by Lorenzo Bettini
+http://www.lorenzobettini.it
+http://www.gnu.org/software/src-highlite -->
+<pre><tt><span style="color: #FF6600">exprs</span> <span style="color: #990000">-></span> <span style="color: #FF6600">expr</span> <span style="color: #990000">:</span> [<span style="color: #FF6600">'$1'</span>]<span style="color: #990000">.</span>
+<span style="color: #FF6600">exprs</span> <span style="color: #990000">-></span> <span style="color: #FF6600">expr</span> <span style="color: #FF6600">','</span> <span style="color: #FF6600">exprs</span> <span style="color: #990000">:</span> [<span style="color: #FF6600">'$1'</span> | <span style="color: #FF6600">'$3'</span>]<span style="color: #990000">.</span></tt></pre></div></div>
+<div class="paragraph"><p>That takes care of everything except the optional trailing
+comma at the end of our lists of expressions. We just need an
+additional rule to take care of this.</p></div>
+<div class="listingblock">
+<div class="content"><!-- Generator: GNU source-highlight 3.1.8
+by Lorenzo Bettini
+http://www.lorenzobettini.it
+http://www.gnu.org/software/src-highlite -->
+<pre><tt><span style="color: #FF6600">exprs</span> <span style="color: #990000">-></span> <span style="color: #FF6600">expr</span> <span style="color: #FF6600">','</span> <span style="color: #990000">:</span> [<span style="color: #FF6600">'$1'</span>]<span style="color: #990000">.</span></tt></pre></div></div>
+<div class="paragraph"><p>That’s it.</p></div>
+<div class="paragraph"><p>Wondering why we don’t have this optional trailing comma in
+Erlang considering how easy it was and the number of people
+complaining about it? Yeah, me too. But that’s for someone else
+to answer.</p></div>
+<div class="paragraph"><p>Another change I want to talk about is a simple modification
+of the compiler code to use an <code>#env{}</code> record for
+tracking state instead of passing around individual variables.
+This will be required later on when we make modules into proper
+expressions so I thought it was a good idea to anticipate.</p></div>
+<div class="ulist"><ul>
+<li>
+<p>
+<a href="https://github.com/extend/xerl/blob/0.4/">View the source</a>
+</p>
+</li>
+</ul></div>
+ +</article> +</div> + +<div class="span3 sidecol"> +<h3>More articles</h3> +<ul id="articles-nav" class="extra_margin"> + + <li><a href="http://ninenines.eu/articles/erlanger-playbook-september-2015-update/">The Erlanger Playbook September 2015 Update</a></li> + + <li><a href="http://ninenines.eu/articles/erlanger-playbook/">The Erlanger Playbook</a></li> + + <li><a href="http://ninenines.eu/articles/erlang-validate-utf8/">Validating UTF-8 binaries with Erlang</a></li> + + <li><a href="http://ninenines.eu/articles/on-open-source/">On open source</a></li> + + <li><a href="http://ninenines.eu/articles/the-story-so-far/">The story so far</a></li> + + <li><a href="http://ninenines.eu/articles/cowboy2-qs/">Cowboy 2.0 and query strings</a></li> + + <li><a href="http://ninenines.eu/articles/january-2014-status/">January 2014 status</a></li> + + <li><a href="http://ninenines.eu/articles/farwest-funded/">Farwest got funded!</a></li> + + <li><a href="http://ninenines.eu/articles/erlang.mk-and-relx/">Build Erlang releases with Erlang.mk and Relx</a></li> + + <li><a href="http://ninenines.eu/articles/xerl-0.5-intermediate-module/">Xerl: intermediate module</a></li> + + <li><a href="http://ninenines.eu/articles/xerl-0.4-expression-separator/">Xerl: expression separator</a></li> + + <li><a href="http://ninenines.eu/articles/erlang-scalability/">Erlang Scalability</a></li> + + <li><a href="http://ninenines.eu/articles/xerl-0.3-atomic-expressions/">Xerl: atomic expressions</a></li> + + <li><a href="http://ninenines.eu/articles/xerl-0.2-two-modules/">Xerl: two modules</a></li> + + <li><a href="http://ninenines.eu/articles/xerl-0.1-empty-modules/">Xerl: empty modules</a></li> + + <li><a href="http://ninenines.eu/articles/ranch-ftp/">Build an FTP Server with Ranch in 30 Minutes</a></li> + + <li><a href="http://ninenines.eu/articles/tictactoe/">Erlang Tic Tac Toe</a></li> + +</ul> + +<h3>Feedback</h3> +<p>Feel free to <a href="mailto:[email protected]">email us</a> +if you found any mistake or need clarification on any of the +articles.</p> + +</div> +</div> +</div> +</div> + + <footer> + <div class="container"> + <div class="row"> + <div class="span6"> + <p id="scroll-top"><a href="#">↑ Scroll to top</a></p> + <nav> + <ul> + <li><a href="mailto:[email protected]" title="Contact us">Contact us</a></li><li><a href="https://github.com/ninenines/ninenines.github.io" title="Github repository">Contribute to this site</a></li> + </ul> + </nav> + </div> + <div class="span6 credits"> + <p><img src="/img/footer_logo.png"></p> + <p>Copyright © Loïc Hoguin 2012-2016</p> + </div> + </div> + </div> + </footer> + + + <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script> + <script src="/js/bootstrap-carousel.js"></script> + <script src="/js/bootstrap-dropdown.js"></script> + <script src="/js/custom.js"></script> + </body> +</html> + |