devdocs/elisp/indenting-macros.html


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 <h3 class="section">Indenting Macros</h3> <p>Within a macro definition, you can use the <code>declare</code> form (see <a href="defining-macros">Defining Macros</a>) to specify how <tt class="key">TAB</tt> should indent calls to the macro. An indentation specification is written like this: </p> <div class="example"> <pre class="example">(declare (indent <var>indent-spec</var>))
</pre>
</div> <p> This results in the <code>lisp-indent-function</code> property being set on the macro name. </p> <p>Here are the possibilities for <var>indent-spec</var>: </p> <dl compact> <dt><code>nil</code></dt> <dd><p>This is the same as no property—use the standard indentation pattern. </p></dd> <dt><code>defun</code></dt> <dd><p>Handle this function like a ‘<samp>def</samp>’ construct: treat the second line as the start of a <em>body</em>. </p></dd> <dt>an integer, <var>number</var>
</dt> <dd><p>The first <var>number</var> arguments of the function are <em>distinguished</em> arguments; the rest are considered the body of the expression. A line in the expression is indented according to whether the first argument on it is distinguished or not. If the argument is part of the body, the line is indented <code>lisp-body-indent</code> more columns than the open-parenthesis starting the containing expression. If the argument is distinguished and is either the first or second argument, it is indented <em>twice</em> that many extra columns. If the argument is distinguished and not the first or second argument, the line uses the standard pattern. </p></dd> <dt>a symbol, <var>symbol</var>
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<p><var>symbol</var> should be a function name; that function is called to calculate the indentation of a line within this expression. The function receives two arguments: </p> <dl compact> <dt><var>pos</var></dt> <dd><p>The position at which the line being indented begins. </p></dd> <dt><var>state</var></dt> <dd><p>The value returned by <code>parse-partial-sexp</code> (a Lisp primitive for indentation and nesting computation) when it parses up to the beginning of this line. </p></dd> </dl> <p>It should return either a number, which is the number of columns of indentation for that line, or a list whose car is such a number. The difference between returning a number and returning a list is that a number says that all following lines at the same nesting level should be indented just like this one; a list says that following lines might call for different indentations. This makes a difference when the indentation is being computed by <kbd>C-M-q</kbd>; if the value is a number, <kbd>C-M-q</kbd> need not recalculate indentation for the following lines until the end of the list. </p>
</dd> </dl><div class="_attribution">
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    Copyright &copy; 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/Indenting-Macros.html" class="_attribution-link">https://www.gnu.org/software/emacs/manual/html_node/elisp/Indenting-Macros.html</a>
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