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| author | Indrajith K L | 2022-12-03 17:00:20 +0530 |
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| committer | Indrajith K L | 2022-12-03 17:00:20 +0530 |
| commit | f5c4671bfbad96bf346bd7e9a21fc4317b4959df (patch) | |
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diff --git a/ctags/docs/parser-cxx.html b/ctags/docs/parser-cxx.html new file mode 100644 index 0000000..5aa52b5 --- /dev/null +++ b/ctags/docs/parser-cxx.html @@ -0,0 +1,396 @@ + +<!DOCTYPE html> + +<html> + <head> + <meta charset="utf-8" /> + <meta name="viewport" content="width=device-width, initial-scale=1.0" /><meta name="generator" content="Docutils 0.17.1: http://docutils.sourceforge.net/" /> + + <title>The new C/C++ parser — Universal Ctags 0.3.0 documentation</title> + <link rel="stylesheet" type="text/css" href="_static/pygments.css" /> + <link rel="stylesheet" type="text/css" href="_static/classic.css" /> + + <script data-url_root="./" id="documentation_options" src="_static/documentation_options.js"></script> + <script src="_static/jquery.js"></script> + <script src="_static/underscore.js"></script> + <script src="_static/doctools.js"></script> + + <link rel="index" title="Index" href="genindex.html" /> + <link rel="search" title="Search" href="search.html" /> + <link rel="next" title="The new HTML parser" href="parser-html.html" /> + <link rel="prev" title="CMake parser" href="parser-cmake.html" /> + </head><body> + <div class="related" role="navigation" aria-label="related navigation"> + <h3>Navigation</h3> + <ul> + <li class="right" style="margin-right: 10px"> + <a href="genindex.html" title="General Index" + accesskey="I">index</a></li> + <li class="right" > + <a href="parser-html.html" title="The new HTML parser" + accesskey="N">next</a> |</li> + <li class="right" > + <a href="parser-cmake.html" title="CMake parser" + accesskey="P">previous</a> |</li> + <li class="nav-item nav-item-0"><a href="index.html">Universal Ctags 0.3.0 documentation</a> »</li> + <li class="nav-item nav-item-1"><a href="parsers.html" accesskey="U">Parsers</a> »</li> + <li class="nav-item nav-item-this"><a href="">The new C/C++ parser</a></li> + </ul> + </div> + + <div class="document"> + <div class="documentwrapper"> + <div class="bodywrapper"> + <div class="body" role="main"> + + <section id="the-new-c-c-parser"> +<span id="cxx"></span><h1>The new C/C++ parser<a class="headerlink" href="#the-new-c-c-parser" title="Permalink to this headline">¶</a></h1> +<dl class="field-list simple"> +<dt class="field-odd">Maintainer</dt> +<dd class="field-odd"><p>Szymon Tomasz Stefanek <<a class="reference external" href="mailto:s.stefanek%40gmail.com">s<span>.</span>stefanek<span>@</span>gmail<span>.</span>com</a>></p> +</dd> +</dl> +<section id="introduction"> +<h2>Introduction<a class="headerlink" href="#introduction" title="Permalink to this headline">¶</a></h2> +<p>The C++ language has strongly evolved since the old C/C++ parser was +written. The old parser was struggling with some of the new features +of the language and has shown signs of reaching its limits. For this +reason in February/March 2016 the C/C++ parser was rewritten from +scratch.</p> +<p>In the first release several outstanding bugs were fixed and some new +features were added. Among them:</p> +<ul class="simple"> +<li><p>Tagging of “using namespace” declarations</p></li> +<li><p>Tagging of function parameters</p></li> +<li><p>Extraction of function parameter types</p></li> +<li><p>Tagging of anonymous structures/unions/classes/enums</p></li> +<li><p>Support for C++11 lambdas (as anonymous functions)</p></li> +<li><p>Support for function-level scopes (for local variables and parameters)</p></li> +<li><p>Extraction of local variables which include calls to constructors</p></li> +<li><p>Extraction of local variables from within the for(), while(), if() +and switch() parentheses.</p></li> +<li><p>Support for function prototypes/declarations with trailing return type</p></li> +</ul> +<p>At the time of writing (March 2016) more features are planned.</p> +</section> +<section id="notable-new-features"> +<h2>Notable New Features<a class="headerlink" href="#notable-new-features" title="Permalink to this headline">¶</a></h2> +<p>Some of the notable new features are described below.</p> +<section id="properties"> +<h3>Properties<a class="headerlink" href="#properties" title="Permalink to this headline">¶</a></h3> +<p>Several properties of functions and variables can be extracted +and placed in a new field called <code class="docutils literal notranslate"><span class="pre">properties</span></code>. +The syntax to enable it is:</p> +<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>ctags ... --fields-c++<span class="o">=</span>+<span class="o">{</span>properties<span class="o">}</span> ... +</pre></div> +</div> +<p>At the time of writing the following properties are reported:</p> +<ul class="simple"> +<li><p><code class="docutils literal notranslate"><span class="pre">virtual</span></code>: a function is marked as virtual</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">static</span></code>: a function/variable is marked as static</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">inline</span></code>: a function implementation is marked as inline</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">explicit</span></code>: a function is marked as explicit</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">extern</span></code>: a function/variable is marked as extern</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">const</span></code>: a function is marked as const</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">pure</span></code>: a virtual function is pure (i.e = 0)</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">override</span></code>: a function is marked as override</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">default</span></code>: a function is marked as default</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">final</span></code>: a function is marked as final</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">delete</span></code>: a function is marked as delete</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">mutable</span></code>: a variable is marked as mutable</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">volatile</span></code>: a function is marked as volatile</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">specialization</span></code>: a function is a template specialization</p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">scopespecialization</span></code>: template specialization of scope <code class="docutils literal notranslate"><span class="pre">a<x>::b()</span></code></p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">deprecated</span></code>: a function is marked as deprecated via <code class="docutils literal notranslate"><span class="pre">__attribute__</span></code></p></li> +<li><p><code class="docutils literal notranslate"><span class="pre">scopedenum</span></code>: a scoped enumeration (C++11)</p></li> +</ul> +</section> +<section id="preprocessor-macros"> +<h3>Preprocessor macros<a class="headerlink" href="#preprocessor-macros" title="Permalink to this headline">¶</a></h3> +<section id="defining-a-macro-from-command-line"> +<h4>Defining a macro from command line<a class="headerlink" href="#defining-a-macro-from-command-line" title="Permalink to this headline">¶</a></h4> +<p>The new parser supports the definition of real preprocessor macros +via the <code class="docutils literal notranslate"><span class="pre">-D</span></code> option. All types of macros are supported, +including the ones with parameters and variable arguments. +Stringification, token pasting and recursive macro expansion are also supported.</p> +<p>Option <code class="docutils literal notranslate"><span class="pre">-I</span></code> is now simply a backward-compatible syntax to define a +macro with no replacement.</p> +<p>The syntax is similar to the corresponding gcc <code class="docutils literal notranslate"><span class="pre">-D</span></code> option.</p> +<p>Some examples follow.</p> +<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>ctags ... -D IGNORE_THIS ... +</pre></div> +</div> +<p>With this commandline the following C/C++ input</p> +<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="kt">int</span> <span class="n">IGNORE_THIS</span> <span class="n">a</span><span class="p">;</span> +</pre></div> +</div> +<p>will be processed as if it was</p> +<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="kt">int</span> <span class="n">a</span><span class="p">;</span> +</pre></div> +</div> +<p>Defining a macro with parameters uses the following syntax:</p> +<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>ctags ... -D <span class="s2">"foreach(arg)=for(arg;;)"</span> ... +</pre></div> +</div> +<p>This example defines <code class="docutils literal notranslate"><span class="pre">for(arg;;)</span></code> as the replacement <code class="docutils literal notranslate"><span class="pre">foreach(arg)</span></code>. +So the following C/C++ input</p> +<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="n">foreach</span><span class="p">(</span><span class="kt">char</span> <span class="o">*</span> <span class="n">p</span><span class="p">,</span><span class="n">pointers</span><span class="p">)</span> +<span class="p">{</span> + +<span class="p">}</span> +</pre></div> +</div> +<p>is processed in new C/C++ parser as:</p> +<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="k">for</span><span class="p">(</span><span class="kt">char</span> <span class="o">*</span> <span class="n">p</span><span class="p">;;)</span> +<span class="p">{</span> + +<span class="p">}</span> +</pre></div> +</div> +<p>and the p local variable can be extracted.</p> +<p>The previous commandline includes quotes since the macros generally contain +characters that are treated specially by the shells. You may need some escaping.</p> +<p>Token pasting is performed by the <code class="docutils literal notranslate"><span class="pre">##</span></code> operator, just like in the normal +C preprocessor.</p> +<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>ctags ... -D <span class="s2">"DECLARE_FUNCTION(prefix)=int prefix ## Call();"</span> +</pre></div> +</div> +<p>So the following code</p> +<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="n">DECLARE_FUNCTION</span><span class="p">(</span><span class="n">a</span><span class="p">)</span> +<span class="n">DECLARE_FUNCTION</span><span class="p">(</span><span class="n">b</span><span class="p">)</span> +</pre></div> +</div> +<p>will be processed as</p> +<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="kt">int</span> <span class="nf">aCall</span><span class="p">();</span> +<span class="kt">int</span> <span class="nf">bCall</span><span class="p">();</span> +</pre></div> +</div> +<p>Macros with variable arguments use the gcc <code class="docutils literal notranslate"><span class="pre">__VA_ARGS__</span></code> syntax.</p> +<div class="highlight-console notranslate"><div class="highlight"><pre><span></span><span class="gp">$ </span>ctags ... -D <span class="s2">"DECLARE_FUNCTION(name,...)=int name(__VA_ARGS__);"</span> +</pre></div> +</div> +<p>So the following code</p> +<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="n">DECLARE_FUNCTION</span><span class="p">(</span><span class="n">x</span><span class="p">,</span><span class="kt">int</span> <span class="n">a</span><span class="p">,</span><span class="kt">int</span> <span class="n">b</span><span class="p">)</span> +</pre></div> +</div> +<p>will be processed as</p> +<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="kt">int</span> <span class="nf">x</span><span class="p">(</span><span class="kt">int</span> <span class="n">a</span><span class="p">,</span><span class="kt">int</span> <span class="n">b</span><span class="p">);</span> +</pre></div> +</div> +</section> +<section id="automatically-expanding-macros-defined-in-the-same-input-file-highly-experimental"> +<h4>Automatically expanding macros defined in the same input file (HIGHLY EXPERIMENTAL)<a class="headerlink" href="#automatically-expanding-macros-defined-in-the-same-input-file-highly-experimental" title="Permalink to this headline">¶</a></h4> +<p>If a CPreProcessor macro defined in a C/C++/CUDA file, the macro invocation in the +SAME file can be expanded with following options:</p> +<div class="highlight-text notranslate"><div class="highlight"><pre><span></span>--param-CPreProcessor:_expand=1 +--fields-C=+{macrodef} +--fields-C++=+{macrodef} +--fields-CUDA=+{macrodef} +--fields=+{signature} +</pre></div> +</div> +<p>Let’s see an example.</p> +<p>input.c: +.. code-block:: C</p> +<blockquote> +<div><p>#define DEFUN(NAME) int NAME (int x, int y) +#define BEGIN { +#define END }</p> +<dl class="simple"> +<dt>DEFUN(myfunc)</dt><dd><p>BEGIN +return -1 +END</p> +</dd> +</dl> +</div></blockquote> +<p>The output without options: +.. code-block:</p> +<div class="highlight-default notranslate"><div class="highlight"><pre><span></span>$ ctags -o - input.c +BEGIN input.c /^#define BEGIN /;" d language:C file: +DEFUN input.c /^#define DEFUN(/;" d language:C file: +END input.c /^#define END /;" d language:C file: +</pre></div> +</div> +<p>The output with options: +.. code-block:</p> +<div class="highlight-default notranslate"><div class="highlight"><pre><span></span>$ ctags --param-CPreProcessor:_expand=1 --fields-C=+'{macrodef}' --fields=+'{signature}' -o - input.c +BEGIN input.c /^#define BEGIN /;" d language:C file: macrodef:{ +DEFUN input.c /^#define DEFUN(/;" d language:C file: signature:(NAME) macrodef:int NAME (int x, int y) +END input.c /^#define END /;" d language:C file: macrodef:} +myfunc input.c /^DEFUN(myfunc)$/;" f language:C typeref:typename:int signature:(int x,int y) +</pre></div> +</div> +<p><code class="docutils literal notranslate"><span class="pre">myfunc</span></code> coded by <code class="docutils literal notranslate"><span class="pre">DEFUN</span></code> macro is captured well.</p> +<p>This feature is highly experimental. At least three limitations are known.</p> +<ul class="simple"> +<li><p>This feature doesn’t understand <code class="docutils literal notranslate"><span class="pre">#undef</span></code> yet. +Once a macro is defined, its invocation is always expanded even +after the parser sees <code class="docutils literal notranslate"><span class="pre">#undef</span></code> for the macro in the same input +file.</p></li> +<li><p>Macros are expanded incorrectly if the result of macro expansion +includes the macro invocation again.</p></li> +<li><p>Currently, ctags can expand a macro invocation only if its +definitions are in the same input file. ctags cannot expand a macro +defined in the header file included from the current input file.</p></li> +</ul> +<p>Enabling this macro expansion feature makes the parsing speed about +two times slower.</p> +</section> +</section> +</section> +<section id="incompatible-changes"> +<h2>Incompatible Changes<a class="headerlink" href="#incompatible-changes" title="Permalink to this headline">¶</a></h2> +<p>The parser is mostly compatible with the old one. There are some minor +incompatible changes which are described below.</p> +<section id="anonymous-structure-names"> +<h3>Anonymous structure names<a class="headerlink" href="#anonymous-structure-names" title="Permalink to this headline">¶</a></h3> +<p>The old parser produced structure names in the form <code class="docutils literal notranslate"><span class="pre">__anonN</span></code> where N +was a number starting at 1 in each file and increasing at each new +structure. This caused collisions in symbol names when ctags was run +on multiple files.</p> +<p>In the new parser the anonymous structure names depend on the file name +being processed and on the type of the structure itself. Collisions are +far less likely (though not impossible as hash functions are unavoidably +imperfect).</p> +<p>Pitfall: the file name used for hashing includes the path as passed to the +ctags executable. So the same file “seen” from different paths will produce +different structure names. This is unavoidable and is up to the user to +ensure that multiple ctags runs are started from a common directory root.</p> +</section> +<section id="file-scope"> +<h3>File scope<a class="headerlink" href="#file-scope" title="Permalink to this headline">¶</a></h3> +<p>The file scope information is not 100% reliable. It never was. +There are several cases in that compiler, linker or even source code +tricks can “unhide” file scope symbols (for instance *.c files can be +included into each other) and several other cases in that the limitation +of the scope of a symbol to a single file simply cannot be determined +with a single pass or without looking at a program as a whole.</p> +<p>The new parser defines a simple policy for file scope association +that tries to be as compatible as possible with the old parser and +should reflect the most common usages. The policy is the following:</p> +<ul class="simple"> +<li><p>Namespaces are in file scope if declared inside a .c or .cpp file</p></li> +<li><p>Function prototypes are in file scope if declared inside a .c or .cpp file</p></li> +<li><p>K&R style function definitions are in file scope if declared static +inside a .c file.</p></li> +<li><p>Function definitions appearing inside a namespace are in file scope only +if declared static inside a .c or .cpp file. +Note that this rule includes both global functions (global namespace) +and class/struct/union members defined outside of the class/struct/union +declaration.</p></li> +<li><p>Function definitions appearing inside a class/struct/union declaration +are in file scope only if declared static inside a .cpp file</p></li> +<li><p>Function parameters are always in file scope</p></li> +<li><p>Local variables are always in file scope</p></li> +<li><p>Variables appearing inside a namespace are in file scope only if +they are declared static inside a .c or .cpp file</p></li> +<li><p>Variables that are members of a class/struct/union are in file scope +only if declared in a .c or .cpp file</p></li> +<li><p>Typedefs are in file scope if appearing inside a .c or .cpp file</p></li> +</ul> +<p>Most of these rules are debatable in one way or the other. Just keep in mind +that this is not 100% reliable.</p> +</section> +<section id="inheritance-information"> +<h3>Inheritance information<a class="headerlink" href="#inheritance-information" title="Permalink to this headline">¶</a></h3> +<p>The new parser does not strip template names from base classes. +For a declaration like</p> +<div class="highlight-C notranslate"><div class="highlight"><pre><span></span><span class="n">template</span><span class="o"><</span><span class="n">typename</span> <span class="n">A</span><span class="o">></span> <span class="n">class</span> <span class="nl">B</span> <span class="p">:</span> <span class="n">public</span> <span class="n">C</span><span class="o"><</span><span class="n">A</span><span class="o">></span> +</pre></div> +</div> +<p>the old parser reported <code class="docutils literal notranslate"><span class="pre">C</span></code> as base class while the new one reports +<code class="docutils literal notranslate"><span class="pre">C<A></span></code>.</p> +</section> +<section id="typeref"> +<h3>Typeref<a class="headerlink" href="#typeref" title="Permalink to this headline">¶</a></h3> +<p>The syntax of the typeref field (<code class="docutils literal notranslate"><span class="pre">typeref:A:B</span></code>) was designed with only +struct/class/union/enum types in mind. Generic types don’t have <code class="docutils literal notranslate"><span class="pre">A</span></code> +information and the keywords became entirely optional in C++: +you just can’t tell. Furthermore, struct/class/union/enum types +share the same namespace and their names can’t collide, so the <code class="docutils literal notranslate"><span class="pre">A</span></code> +information is redundant for most purposes.</p> +<p>To accommodate generic types and preserve some degree of backward +compatibility the new parser uses struct/class/union/enum in place +of <code class="docutils literal notranslate"><span class="pre">A</span></code> where such keyword can be inferred. Where the information is +not available it uses the ‘typename’ keyword.</p> +<p>Generally, you should ignore the information in field <code class="docutils literal notranslate"><span class="pre">A</span></code> and use +only information in field <code class="docutils literal notranslate"><span class="pre">B</span></code>.</p> +</section> +</section> +</section> + + + <div class="clearer"></div> + </div> + </div> + </div> + <div class="sphinxsidebar" role="navigation" aria-label="main navigation"> + <div class="sphinxsidebarwrapper"> + <h3><a href="index.html">Table of Contents</a></h3> + <ul> +<li><a class="reference internal" href="#">The new C/C++ parser</a><ul> +<li><a class="reference internal" href="#introduction">Introduction</a></li> +<li><a class="reference internal" href="#notable-new-features">Notable New Features</a><ul> +<li><a class="reference internal" href="#properties">Properties</a></li> +<li><a class="reference internal" href="#preprocessor-macros">Preprocessor macros</a><ul> +<li><a class="reference internal" href="#defining-a-macro-from-command-line">Defining a macro from command line</a></li> +<li><a class="reference internal" href="#automatically-expanding-macros-defined-in-the-same-input-file-highly-experimental">Automatically expanding macros defined in the same input file (HIGHLY EXPERIMENTAL)</a></li> +</ul> +</li> +</ul> +</li> +<li><a class="reference internal" href="#incompatible-changes">Incompatible Changes</a><ul> +<li><a class="reference internal" href="#anonymous-structure-names">Anonymous structure names</a></li> +<li><a class="reference internal" href="#file-scope">File scope</a></li> +<li><a class="reference internal" href="#inheritance-information">Inheritance information</a></li> +<li><a class="reference internal" href="#typeref">Typeref</a></li> +</ul> +</li> +</ul> +</li> +</ul> + + <h4>Previous topic</h4> + <p class="topless"><a href="parser-cmake.html" + title="previous chapter">CMake parser</a></p> + <h4>Next topic</h4> + <p class="topless"><a href="parser-html.html" + title="next chapter">The new HTML parser</a></p> +<div id="searchbox" style="display: none" role="search"> + <h3 id="searchlabel">Quick search</h3> + <div class="searchformwrapper"> + <form class="search" action="search.html" method="get"> + <input type="text" name="q" aria-labelledby="searchlabel" /> + <input type="submit" value="Go" /> + </form> + </div> +</div> +<script>$('#searchbox').show(0);</script> + </div> + </div> + <div class="clearer"></div> + </div> + <div class="related" role="navigation" aria-label="related navigation"> + <h3>Navigation</h3> + <ul> + <li class="right" style="margin-right: 10px"> + <a href="genindex.html" title="General Index" + >index</a></li> + <li class="right" > + <a href="parser-html.html" title="The new HTML parser" + >next</a> |</li> + <li class="right" > + <a href="parser-cmake.html" title="CMake parser" + >previous</a> |</li> + <li class="nav-item nav-item-0"><a href="index.html">Universal Ctags 0.3.0 documentation</a> »</li> + <li class="nav-item nav-item-1"><a href="parsers.html" >Parsers</a> »</li> + <li class="nav-item nav-item-this"><a href="">The new C/C++ parser</a></li> + </ul> + </div> + <div class="footer" role="contentinfo"> + © Copyright 2015, Universal Ctags Team. + Last updated on 11 Jun 2021. + Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 4.0.2. + </div> + </body> +</html>
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