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<h3 class="section">Syntax Table Functions</h3> <p>In this section we describe functions for creating, accessing and altering syntax tables. </p> <dl> <dt id="make-syntax-table">Function: <strong>make-syntax-table</strong> <em>&optional table</em>
</dt> <dd>
<p>This function creates a new syntax table. If <var>table</var> is non-<code>nil</code>, the parent of the new syntax table is <var>table</var>; otherwise, the parent is the standard syntax table. </p> <p>In the new syntax table, all characters are initially given the “inherit” (‘<samp>@</samp>’) syntax class, i.e., their syntax is inherited from the parent table (see <a href="syntax-class-table">Syntax Class Table</a>). </p>
</dd>
</dl> <dl> <dt id="copy-syntax-table">Function: <strong>copy-syntax-table</strong> <em>&optional table</em>
</dt> <dd><p>This function constructs a copy of <var>table</var> and returns it. If <var>table</var> is omitted or <code>nil</code>, it returns a copy of the standard syntax table. Otherwise, an error is signaled if <var>table</var> is not a syntax table. </p></dd>
</dl> <dl> <dt id="modify-syntax-entry">Command: <strong>modify-syntax-entry</strong> <em>char syntax-descriptor &optional table</em>
</dt> <dd>
<p>This function sets the syntax entry for <var>char</var> according to <var>syntax-descriptor</var>. <var>char</var> must be a character, or a cons cell of the form <code>(<var>min</var> . <var>max</var>)</code>; in the latter case, the function sets the syntax entries for all characters in the range between <var>min</var> and <var>max</var>, inclusive. </p> <p>The syntax is changed only for <var>table</var>, which defaults to the current buffer’s syntax table, and not in any other syntax table. </p> <p>The argument <var>syntax-descriptor</var> is a syntax descriptor, i.e., a string whose first character is a syntax class designator and whose second and subsequent characters optionally specify a matching character and syntax flags. See <a href="syntax-descriptors">Syntax Descriptors</a>. An error is signaled if <var>syntax-descriptor</var> is not a valid syntax descriptor. </p> <p>This function always returns <code>nil</code>. The old syntax information in the table for this character is discarded. </p> <div class="example"> <pre class="example"><span class="roman">Examples:</span>
</pre>
<pre class="example">
;; <span class="roman">Put the space character in class whitespace.</span>
(modify-syntax-entry ?\s " ")
⇒ nil
</pre>
<pre class="example">;; <span class="roman">Make ‘<samp>$</samp>’ an open parenthesis character,</span>
;; <span class="roman">with ‘<samp>^</samp>’ as its matching close.</span>
(modify-syntax-entry ?$ "(^")
⇒ nil
</pre>
<pre class="example">;; <span class="roman">Make ‘<samp>^</samp>’ a close parenthesis character,</span>
;; <span class="roman">with ‘<samp>$</samp>’ as its matching open.</span>
(modify-syntax-entry ?^ ")$")
⇒ nil
</pre>
<pre class="example">;; <span class="roman">Make ‘<samp>/</samp>’ a punctuation character,</span>
;; <span class="roman">the first character of a start-comment sequence,</span>
;; <span class="roman">and the second character of an end-comment sequence.</span>
;; <span class="roman">This is used in C mode.</span>
(modify-syntax-entry ?/ ". 14")
⇒ nil
</pre>
</div> </dd>
</dl> <dl> <dt id="char-syntax">Function: <strong>char-syntax</strong> <em>character</em>
</dt> <dd>
<p>This function returns the syntax class of <var>character</var>, represented by its designator character (see <a href="syntax-class-table">Syntax Class Table</a>). This returns <em>only</em> the class, not its matching character or syntax flags. </p> <p>The following examples apply to C mode. (We use <code>string</code> to make it easier to see the character returned by <code>char-syntax</code>.) </p> <div class="example"> <pre class="example">;; Space characters have whitespace syntax class.
(string (char-syntax ?\s))
⇒ " "
</pre>
<pre class="example">;; Forward slash characters have punctuation syntax.
;; Note that this <code>char-syntax</code> call does not reveal
;; that it is also part of comment-start and -end sequences.
(string (char-syntax ?/))
⇒ "."
</pre>
<pre class="example">;; Open parenthesis characters have open parenthesis syntax.
;; Note that this <code>char-syntax</code> call does not reveal that
;; it has a matching character, ‘<samp>)</samp>’.
(string (char-syntax ?\())
⇒ "("
</pre>
</div> </dd>
</dl> <dl> <dt id="set-syntax-table">Function: <strong>set-syntax-table</strong> <em>table</em>
</dt> <dd><p>This function makes <var>table</var> the syntax table for the current buffer. It returns <var>table</var>. </p></dd>
</dl> <dl> <dt id="syntax-table">Function: <strong>syntax-table</strong>
</dt> <dd><p>This function returns the current syntax table, which is the table for the current buffer. </p></dd>
</dl> <dl> <dt id="describe-syntax">Command: <strong>describe-syntax</strong> <em>&optional buffer</em>
</dt> <dd><p>This command displays the contents of the syntax table of <var>buffer</var> (by default, the current buffer) in a help buffer. </p></dd>
</dl> <dl> <dt id="with-syntax-table">Macro: <strong>with-syntax-table</strong> <em>table body…</em>
</dt> <dd>
<p>This macro executes <var>body</var> using <var>table</var> as the current syntax table. It returns the value of the last form in <var>body</var>, after restoring the old current syntax table. </p> <p>Since each buffer has its own current syntax table, we should make that more precise: <code>with-syntax-table</code> temporarily alters the current syntax table of whichever buffer is current at the time the macro execution starts. Other buffers are not affected. </p>
</dd>
</dl><div class="_attribution">
<p class="_attribution-p">
Copyright © 1990-1996, 1998-2022 Free Software Foundation, Inc. <br>Licensed under the GNU GPL license.<br>
<a href="https://www.gnu.org/software/emacs/manual/html_node/elisp/Syntax-Table-Functions.html" class="_attribution-link">https://www.gnu.org/software/emacs/manual/html_node/elisp/Syntax-Table-Functions.html</a>
</p>
</div>
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