<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Getting started — D:YAML 0.4 documentation</title> <link rel="stylesheet" href="../_static/default.css" type="text/css" /> <link rel="stylesheet" href="../_static/pygments.css" type="text/css" /> <script type="text/javascript"> var DOCUMENTATION_OPTIONS = { URL_ROOT: '../', VERSION: '0.4', COLLAPSE_INDEX: false, FILE_SUFFIX: '.html', HAS_SOURCE: true }; </script> <script type="text/javascript" src="../_static/jquery.js"></script> <script type="text/javascript" src="../_static/underscore.js"></script> <script type="text/javascript" src="../_static/doctools.js"></script> <link rel="top" title="D:YAML 0.4 documentation" href="../index.html" /> <link rel="next" title="Custom YAML data types" href="custom_types.html" /> <link rel="prev" title="Welcome to D:YAML documentation!" href="../index.html" /> </head> <body> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="custom_types.html" title="Custom YAML data types" accesskey="N">next</a></li> <li class="right" > <a href="../index.html" title="Welcome to D:YAML documentation!" accesskey="P">previous</a> |</li> <li><a href="../index.html">D:YAML 0.4 documentation</a> »</li> </ul> </div> <div class="document"> <div class="documentwrapper"> <div class="bodywrapper"> <div class="body"> <div class="section" id="getting-started"> <h1>Getting started<a class="headerlink" href="#getting-started" title="Permalink to this headline">¶</a></h1> <p>Welcome to D:YAML! D:YAML is a <a class="reference external" href="http://en.wikipedia.org/wiki/YAML">YAML</a> parser library for the <a class="reference external" href="http://dlang.org">D programming language</a>. This tutorial will explain how to set D:YAML up and use it in your projects.</p> <p>This is meant to be the <strong>simplest possible</strong> introduction to D:YAML. Some of this information might already be known to you. Only basic usage is covered.</p> <div class="section" id="setting-up"> <h2>Setting up<a class="headerlink" href="#setting-up" title="Permalink to this headline">¶</a></h2> <div class="section" id="install-the-dmd-compiler"> <h3>Install the DMD compiler<a class="headerlink" href="#install-the-dmd-compiler" title="Permalink to this headline">¶</a></h3> <p>Digital Mars D compiler, or DMD, is the most commonly used D compiler. You can find its newest version <a class="reference external" href="http://dlang.org/download.html">here</a>. Download the version of DMD for your operating system and install it.</p> <div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">Other D compilers exist, such as <a class="reference external" href="http://bitbucket.org/goshawk/gdc/wiki/Home">GDC</a> and <a class="reference external" href="http://www.dsource.org/projects/ldc/">LDC</a>. Setting up with either one of them should be similar to DMD, but they are not yet as stable as DMD.</p> </div> </div> <div class="section" id="download-and-compile-d-yaml"> <h3>Download and compile D:YAML<a class="headerlink" href="#download-and-compile-d-yaml" title="Permalink to this headline">¶</a></h3> <p>The newest version of D:YAML can be found <a class="reference external" href="https://github.com/Kiith-Sa/D-YAML">here</a>. Download a source archive, extract it, and move to the extracted directory.</p> <p>D:YAML uses a modified version of the <a class="reference external" href="http://dsource.org/projects/cdc/">CDC</a> script for compilation. To compile D:YAML, you first need to build CDC. Do this by typing the following command into the console:</p> <div class="highlight-python"><pre>dmd cdc.d</pre> </div> <p>Now compile D:YAML with CDC. To do this on Unix/Linux, use the following command:</p> <div class="highlight-python"><pre>./cdc</pre> </div> <p>On Windows:</p> <div class="highlight-python"><div class="highlight"><pre><span class="n">cdc</span><span class="o">.</span><span class="n">exe</span> </pre></div> </div> <p>This will compile the library to a file called <tt class="docutils literal"><span class="pre">libdyaml.a</span></tt> on Unix/Linux or <tt class="docutils literal"><span class="pre">libdyaml.lib</span></tt> on Windows.</p> </div> </div> <div class="section" id="your-first-d-yaml-project"> <h2>Your first D:YAML project<a class="headerlink" href="#your-first-d-yaml-project" title="Permalink to this headline">¶</a></h2> <p>Create a directory for your project and in that directory, create a file called <tt class="docutils literal"><span class="pre">input.yaml</span></tt> with the following contents:</p> <div class="highlight-yaml"><div class="highlight"><pre><span class="l-Scalar-Plain">Hello World</span> <span class="p-Indicator">:</span> <span class="p-Indicator">-</span> <span class="l-Scalar-Plain">Hello</span> <span class="p-Indicator">-</span> <span class="l-Scalar-Plain">World</span> <span class="l-Scalar-Plain">Answer</span><span class="p-Indicator">:</span> <span class="l-Scalar-Plain">42</span> </pre></div> </div> <p>This will serve as input for our example.</p> <p>Now we need to parse it. Create a file called <tt class="docutils literal"><span class="pre">main.d</span></tt>. Paste following code into the file:</p> <div class="highlight-d"><div class="highlight"><pre><span class="k">import</span> <span class="n">std</span><span class="p">.</span><span class="n">stdio</span><span class="p">;</span> <span class="k">import</span> <span class="n">dyaml</span><span class="p">.</span><span class="n">all</span><span class="p">;</span> <span class="kt">void</span> <span class="n">main</span><span class="p">()</span> <span class="p">{</span> <span class="c1">//Read the input.</span> <span class="n">Node</span> <span class="n">root</span> <span class="p">=</span> <span class="n">Loader</span><span class="p">(</span><span class="s">"input.yaml"</span><span class="p">).</span><span class="n">load</span><span class="p">();</span> <span class="c1">//Display the data read.</span> <span class="k">foreach</span><span class="p">(</span><span class="nb">string</span> <span class="n">word</span><span class="p">;</span> <span class="n">root</span><span class="p">[</span><span class="s">"Hello World"</span><span class="p">])</span> <span class="p">{</span> <span class="n">writeln</span><span class="p">(</span><span class="n">word</span><span class="p">);</span> <span class="p">}</span> <span class="n">writeln</span><span class="p">(</span><span class="s">"The answer is "</span><span class="p">,</span> <span class="n">root</span><span class="p">[</span><span class="s">"Answer"</span><span class="p">].</span><span class="n">as</span><span class="p">!</span><span class="kt">int</span><span class="p">);</span> <span class="c1">//Dump the loaded document to output.yaml.</span> <span class="n">Dumper</span><span class="p">(</span><span class="s">"output.yaml"</span><span class="p">).</span><span class="n">dump</span><span class="p">(</span><span class="n">root</span><span class="p">);</span> <span class="p">}</span> </pre></div> </div> <div class="section" id="explanation-of-the-code"> <h3>Explanation of the code<a class="headerlink" href="#explanation-of-the-code" title="Permalink to this headline">¶</a></h3> <p>First, we import the <em>dyaml.all</em> module. This is the only D:YAML module you need to import - it automatically imports all needed modules.</p> <p>Next we load the file using the <em>Loader.load()</em> method. <em>Loader</em> is a struct used for parsing YAML documents. The <em>load()</em> method loads the file as <strong>one</strong> YAML document, or throws <em>YAMLException</em>, D:YAML exception type, if the file could not be parsed or does not contain exactly one document. Note that we don’t do any error checking here in order to keep the example as simple as possible.</p> <p><em>Node</em> represents a node in a YAML document. It can be a sequence (array), mapping (associative array) or a scalar (value). Here the root node is a mapping, and we use the index operator to get subnodes with keys “Hello World” and “Answer”. We iterate over the first, as it is a sequence, and use the <em>Node.as()</em> method on the second to read its value as an integer.</p> <p>You can iterate over a mapping or sequence as if it was an associative or normal array. If you try to iterate over a scalar, it will throw a <em>YAMLException</em>.</p> <p>You can iterate over subnodes using <em>Node</em> as the iterated type, or specify the type subnodes are expected to have. D:YAML will automatically convert iterated subnodes to that type if possible. Here we specify the <em>string</em> type, so we iterate over the “Hello World” sequence as an array of strings. If it is not possible to convert to iterated type, a <em>YAMLException</em> is thrown. For instance, if we specified <em>int</em> here, we would get an error, as “Hello” cannot be converted to an integer.</p> <p>The <em>Node.as()</em> method is used to read value of a scalar node as specified type. D:YAML will try to return the scalar as this type, converting if needed, throwing <em>YAMLException</em> if not possible.</p> <p>Finally we dump the document we just read to <tt class="docutils literal"><span class="pre">output.yaml</span></tt> with the <em>Dumper.dump()</em> method. <em>Dumper</em> is a struct used to dump YAML documents. The <em>dump()</em> method writes one or more documents to a file, throwing <em>YAMLException</em> if the file could not be written to.</p> <p>D:YAML doesn’t preserve style information in documents, so even though <tt class="docutils literal"><span class="pre">output.yaml</span></tt> will contain the same data as <tt class="docutils literal"><span class="pre">input.yaml</span></tt>, it might be formatted differently. Comments are not preserved, either.</p> </div> <div class="section" id="compiling"> <h3>Compiling<a class="headerlink" href="#compiling" title="Permalink to this headline">¶</a></h3> <p>To compile your project, DMD needs to know which directories contain the imported modules and the library. You also need to tell it to link with D:YAML. The import directory should be the <tt class="docutils literal"><span class="pre">source</span></tt> subdirectory of the D:YAML directory. You can specify it using the <tt class="docutils literal"><span class="pre">-I</span></tt> option of DMD. The library directory should point to the compiled library. On Unix/Linux you can specify it using the <tt class="docutils literal"><span class="pre">-L-L</span></tt> option, and link with D:YAML using the <tt class="docutils literal"><span class="pre">-L-l</span></tt> option. On Windows, the import directory is used as the library directory. To link with the library on Windows, just add the path to it relative to the current directory.</p> <p>For example, if you extracted and compiled D:YAML in <tt class="docutils literal"><span class="pre">/home/xxx/dyaml</span></tt>, your project is in <tt class="docutils literal"><span class="pre">/home/xxx/dyaml-project</span></tt>, and you are currently in that directory, compile the project with the following command on Unix/Linux:</p> <div class="highlight-python"><pre>dmd -I../dyaml/source -L-L../dyaml -L-ldyaml main.d</pre> </div> <p>And the following on Windows:</p> <div class="highlight-python"><pre>dmd -I../dyaml/source ../dyaml/libdyaml.lib main.d</pre> </div> <p>This will produce an executable called <tt class="docutils literal"><span class="pre">main</span></tt> or <tt class="docutils literal"><span class="pre">main.exe</span></tt> in your directory. When you run it, it should produce the following output:</p> <div class="highlight-python"><pre>Hello World The answer is 42</pre> </div> </div> <div class="section" id="conclusion"> <h3>Conclusion<a class="headerlink" href="#conclusion" title="Permalink to this headline">¶</a></h3> <p>You should now have a basic idea about how to use D:YAML. To learn more, look at the <a class="reference external" href="../api/index.html">API documentation</a> and other tutorials. You can find code for this example in the <tt class="docutils literal"><span class="pre">example/getting_started</span></tt> directory in the package.</p> </div> </div> </div> </div> </div> </div> <div class="sphinxsidebar"> <div class="sphinxsidebarwrapper"> <p class="logo"><a href="../index.html"> <img class="logo" src="../_static/logo210.png" alt="Logo"/> </a></p> <h3><a href="../index.html">Table Of Contents</a></h3> <ul> <li><a class="reference internal" href="#">Getting started</a><ul> <li><a class="reference internal" href="#setting-up">Setting up</a><ul> <li><a class="reference internal" href="#install-the-dmd-compiler">Install the DMD compiler</a></li> <li><a class="reference internal" href="#download-and-compile-d-yaml">Download and compile D:YAML</a></li> </ul> </li> <li><a class="reference internal" href="#your-first-d-yaml-project">Your first D:YAML project</a><ul> <li><a class="reference internal" href="#explanation-of-the-code">Explanation of the code</a></li> <li><a class="reference internal" href="#compiling">Compiling</a></li> <li><a class="reference internal" href="#conclusion">Conclusion</a></li> </ul> </li> </ul> </li> </ul> </div> </div> <div class="clearer"></div> </div> <div class="related"> <h3>Navigation</h3> <ul> <li class="right" style="margin-right: 10px"> <a href="custom_types.html" title="Custom YAML data types" >next</a></li> <li class="right" > <a href="../index.html" title="Welcome to D:YAML documentation!" >previous</a> |</li> <li><a href="../index.html">D:YAML 0.4 documentation</a> »</li> </ul> </div> <div class="footer"> © Copyright 2011-2014, Ferdinand Majerech. Based on PyYAML http://www.pyyaml.org by Kirill Simonov. Last updated on May 19, 2014. Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 1.1.3. </div> </body> </html>