Eiyeron
/
luwra


			
				
					
						
						
							123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212
							<!DOCTYPE html>
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  
  
  
  <title>Advanced - Luwra</title>
  

  <link rel="shortcut icon" href="../img/favicon.ico">

  
  <link href='https://fonts.googleapis.com/css?family=Lato:400,700|Roboto+Slab:400,700|Inconsolata:400,700' rel='stylesheet' type='text/css'>

  <link rel="stylesheet" href="../css/theme.css" type="text/css" />
  <link rel="stylesheet" href="../css/theme_extra.css" type="text/css" />
  <link rel="stylesheet" href="../css/highlight.css">

  
  <script>
    // Current page data
    var mkdocs_page_name = "Advanced";
    var mkdocs_page_input_path = "advanced.md";
    var mkdocs_page_url = "/advanced/";
  </script>
  
  <script src="../js/jquery-2.1.1.min.js"></script>
  <script src="../js/modernizr-2.8.3.min.js"></script>
  <script type="text/javascript" src="../js/highlight.pack.js"></script>
  <script src="../js/theme.js"></script> 

  
</head>

<body class="wy-body-for-nav" role="document">

  <div class="wy-grid-for-nav">

    
    <nav data-toggle="wy-nav-shift" class="wy-nav-side stickynav">
      <div class="wy-side-nav-search">
        <a href=".." class="icon icon-home"> Luwra</a>
        <div role="search">
  <form id ="rtd-search-form" class="wy-form" action="../search.html" method="get">
    <input type="text" name="q" placeholder="Search docs" />
  </form>
</div>
      </div>

      <div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
        <ul class="current">
          
            <li>
    <li class="toctree-l1 ">
        <a class="" href="..">Home</a>
        
    </li>
<li>
          
            <li>
    <li class="toctree-l1 ">
        <a class="" href="../basics/">Basics</a>
        
    </li>
<li>
          
            <li>
    <li class="toctree-l1 current">
        <a class="current" href="./">Advanced</a>
        
            <ul>
            
                <li class="toctree-l3"><a href="#operating-on-lua-values-with-c-functions">Operating on Lua values with C++ functions</a></li>
                
                    <li><a class="toctree-l4" href="#invoke-a-callable-with-lua-values">Invoke a Callable with Lua values</a></li>
                
                    <li><a class="toctree-l4" href="#invoke-a-function-with-lua-values">Invoke a function with Lua values</a></li>
                
            
            </ul>
        
    </li>
<li>
          
            <li>
    <li class="toctree-l1 ">
        <a class="" href="../miscellaneous/">Miscellaneous</a>
        
    </li>
<li>
          
        </ul>
      </div>
      &nbsp;
    </nav>

    <section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">

      
      <nav class="wy-nav-top" role="navigation" aria-label="top navigation">
        <i data-toggle="wy-nav-top" class="fa fa-bars"></i>
        <a href="..">Luwra</a>
      </nav>

      
      <div class="wy-nav-content">
        <div class="rst-content">
          <div role="navigation" aria-label="breadcrumbs navigation">
  <ul class="wy-breadcrumbs">
    <li><a href="..">Docs</a> &raquo;</li>
    
      
    
    <li>Advanced</li>
    <li class="wy-breadcrumbs-aside">
      
        
          <a href="https://github.com/vapourismo/luwra" class="icon icon-github"> Edit on GitHub</a>
        
      
    </li>
  </ul>
  <hr/>
</div>
          <div role="main">
            <div class="section">
              
                <h1 id="operating-on-lua-values-with-c-functions">Operating on Lua values with C++ functions</h1>
<p>Instead of extracting every Lua value seperately and pushing the result of your C++ function back
onto the stack again, you can use one of the following functions to make this process easier for you.</p>
<h2 id="invoke-a-callable-with-lua-values">Invoke a Callable with Lua values</h2>
<p>The function <a href="../reference/namespaceluwra.html#aa20e363f38b3ae5a168cf40365f5646a">direct</a>
lets you specify a <em>stack signature</em> in order to extract the values and invoke a <code>Callable</code> with
them.</p>
<p>Consider the following:</p>
<pre><code class="c++">string result = foo(luwra::read&lt;string&gt;(lua, n), luwra::read&lt;int&gt;(lua, n + 1));
</code></pre>

<p>It could be rewritting like this:</p>
<pre><code class="c++">string result = luwra::direct&lt;string(string, int)&gt;(lua, n, foo);
</code></pre>

<p><strong>Note:</strong> The result of <code>foo</code> is not pushed onto the stack. Besides the extraction of Lua values
everything happens on the C++ side.</p>
<h2 id="invoke-a-function-with-lua-values">Invoke a function with Lua values</h2>
<p><a href="../reference/namespaceluwra.html#a839077ddd9c3d0565a40c574bc8e9555">apply</a> is similiar to
<a href="../reference/namespaceluwra.html#aa20e363f38b3ae5a168cf40365f5646a">direct</a>. The function <code>apply</code>
provides specific overloads for function pointers and function objects. Although <code>direct</code> works
with function pointers and function objects, it is often more convenient to use <code>apply</code> since it
allows the compiler to infer the <em>stack signature</em> without providing a template parameter.</p>
<p>Provided a function <code>foo</code> which has been declared as used in the example above:</p>
<pre><code class="c++">string foo(string bar, int baz);

// ... or with a function object
std::function&lt;string(string, int)&gt; foo = /* magic */;
</code></pre>

<p>One would use <code>foo</code> like this:</p>
<pre><code class="c++">string result = luwra::apply(lua, n, foo);
</code></pre>
              
            </div>
          </div>
          <footer>
  
    <div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
      
        <a href="../miscellaneous/" class="btn btn-neutral float-right" title="Miscellaneous">Next <span class="icon icon-circle-arrow-right"></span></a>
      
      
        <a href="../basics/" class="btn btn-neutral" title="Basics"><span class="icon icon-circle-arrow-left"></span> Previous</a>
      
    </div>
  

  <hr/>

  <div role="contentinfo">
    <!-- Copyright etc -->
    
  </div>

  Built with <a href="http://www.mkdocs.org">MkDocs</a> using a <a href="https://github.com/snide/sphinx_rtd_theme">theme</a> provided by <a href="https://readthedocs.org">Read the Docs</a>.
</footer>
	  
        </div>
      </div>

    </section>

  </div>

<div class="rst-versions" role="note" style="cursor: pointer">
    <span class="rst-current-version" data-toggle="rst-current-version">
      
          <a href="https://github.com/vapourismo/luwra" class="icon icon-github" style="float: left; color: #fcfcfc"> GitHub</a>
      
      
        <span><a href="../basics/" style="color: #fcfcfc;">&laquo; Previous</a></span>
      
      
        <span style="margin-left: 15px"><a href="../miscellaneous/" style="color: #fcfcfc">Next &raquo;</a></span>
      
    </span>
</div>

</body>
</html>