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<title>Parsing Program Source (GNU Emacs Lisp Reference Manual)</title>
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<div class="chapter" id="Parsing-Program-Source">
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<p>
Next: <a href="Abbrevs.html" accesskey="n" rel="next">Abbrevs and Abbrev Expansion</a>, Previous: <a href="Syntax-Tables.html" accesskey="p" rel="prev">Syntax Tables</a>, Up: <a href="index.html" accesskey="u" rel="up">Emacs Lisp</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html" title="Index" rel="index">Index</a>]</p>
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<hr>
<span id="Parsing-Program-Source-1"></span><h2 class="chapter">37 Parsing Program Source</h2>
<span id="index-syntax-tree_002c-from-parsing-program-source"></span>
<p>Emacs provides various ways to parse program source text and produce a
<em>syntax tree</em>. In a syntax tree, text is no longer considered a
one-dimensional stream of characters, but a structured tree of nodes,
where each node representing a piece of text. Thus, a syntax tree can
enable interesting features like precise fontification, indentation,
navigation, structured editing, etc.
</p>
<p>Emacs has a simple facility for parsing balanced expressions
(see <a href="Parsing-Expressions.html">Parsing Expressions</a>). There is also the SMIE library for
generic navigation and indentation (see <a href="SMIE.html">Simple Minded Indentation Engine</a>).
</p>
<p>In addition to those, Emacs also provides integration with
<a href="https://tree-sitter.github.io/tree-sitter">the tree-sitter
library</a>) if support for it was compiled in. The tree-sitter library
implements an incremental parser and has support from a wide range of
programming languages.
</p>
<dl class="def">
<dt id="index-treesit_002davailable_002dp"><span class="category">Function: </span><span><strong>treesit-available-p</strong><a href='#index-treesit_002davailable_002dp' class='copiable-anchor'> ¶</a></span></dt>
<dd><p>This function returns non-<code>nil</code> if tree-sitter features are
available for the current Emacs session.
</p></dd></dl>
<p>To be able to parse the program source using the tree-sitter library
and access the syntax tree of the program, a Lisp program needs to
load a language definition library, and create a parser for that
language and the current buffer. After that, the Lisp program can
query the parser about specific nodes of the syntax tree. Then, it
can access various kinds of information about each node, and search
for nodes using a powerful pattern-matching syntax. This chapter
explains how to do all this, and also how a Lisp program can work with
source files that mix multiple programming languages.
</p>
<ul class="section-toc">
<li><a href="Language-Definitions.html" accesskey="1">Tree-sitter Language Definitions</a></li>
<li><a href="Using-Parser.html" accesskey="2">Using Tree-sitter Parser</a></li>
<li><a href="Retrieving-Nodes.html" accesskey="3">Retrieving Nodes</a></li>
<li><a href="Accessing-Node-Information.html" accesskey="4">Accessing Node Information</a></li>
<li><a href="Pattern-Matching.html" accesskey="5">Pattern Matching Tree-sitter Nodes</a></li>
<li><a href="Multiple-Languages.html" accesskey="6">Parsing Text in Multiple Languages</a></li>
<li><a href="Tree_002dsitter-major-modes.html" accesskey="7">Developing major modes with tree-sitter</a></li>
<li><a href="Tree_002dsitter-C-API.html" accesskey="8">Tree-sitter C API Correspondence</a></li>
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