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<h1 class="title">Expanding snippets</h1>
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<li>
<a title="" href="index.html">Intro and tutorial</a>
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<li>
<a title="" href="snippet-organization.html">Howto: organize</a>
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<a title="" href="snippet-expansion.html">Howto: expand</a>
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<p>
<b>Important:</b> This documentation applies to
the <b>SVN trunk</b> of YASnippet, which you
get <a href="http://code.google.com/p/yasnippet/source/checkout">here</a>. Documentation
for other versions can be found <a title=""
href="http://code.google.com/p/yasnippet/downloads/list">here</a>.
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<div class="contents topic" id="contents">
<p class="topic-title first">Contents</p>
<ul class="simple">
<li><a class="reference internal" href="#triggering-expansion" id="id2">Triggering expansion</a><ul>
<li><a class="reference internal" href="#trigger-key" id="id3">Trigger key</a><ul>
<li><a class="reference internal" href="#fallback-bahaviour" id="id4">Fallback bahaviour</a></li>
</ul>
</li>
<li><a class="reference internal" href="#insert-at-point" id="id5">Insert at point</a></li>
<li><a class="reference internal" href="#snippet-keybinding" id="id6">Snippet keybinding</a></li>
<li><a class="reference internal" href="#expanding-from-the-menu" id="id7">Expanding from the menu</a></li>
<li><a class="reference internal" href="#expanding-with-hippie-expand" id="id8">Expanding with <tt class="docutils literal"><span class="pre">hippie-expand</span></tt></a></li>
<li><a class="reference internal" href="#expanding-from-emacs-lisp-code" id="id9">Expanding from emacs-lisp code</a></li>
</ul>
</li>
<li><a class="reference internal" href="#controlling-expansion" id="id10">Controlling expansion</a><ul>
<li><a class="reference internal" href="#eligible-snippets" id="id11">Eligible snippets</a></li>
<li><a class="reference internal" href="#the-condition-system" id="id12">The condition system</a></li>
<li><a class="reference internal" href="#multiples-snippet-with-the-same-key" id="id13">Multiples snippet with the same key</a><ul>
<li><a class="reference internal" href="#use-the-x-window-system" id="id14">Use the X window system</a></li>
<li><a class="reference internal" href="#minibuffer-prompting" id="id15">Minibuffer prompting</a></li>
<li><a class="reference internal" href="#use-dropdown-menu-el" id="id16">Use <tt class="docutils literal"><span class="pre">dropdown-menu.el</span></tt></a></li>
<li><a class="reference internal" href="#roll-your-own" id="id17">Roll your own</a></li>
</ul>
</li>
</ul>
</li>
<li><a class="reference internal" href="#customizable-variables" id="id18">Customizable Variables</a><ul>
<li><a class="reference internal" href="#yas-prompt-functions" id="id19"><tt class="docutils literal"><span class="pre">yas/prompt-functions</span></tt></a></li>
<li><a class="reference internal" href="#yas-fallback-behavior" id="id20"><tt class="docutils literal"><span class="pre">yas/fallback-behavior</span></tt></a></li>
<li><a class="reference internal" href="#yas-choose-keys-first" id="id21"><tt class="docutils literal"><span class="pre">yas/choose-keys-first</span></tt></a></li>
<li><a class="reference internal" href="#yas-choose-tables-first" id="id22"><tt class="docutils literal"><span class="pre">yas/choose-tables-first</span></tt></a></li>
<li><a class="reference internal" href="#yas-key-syntaxes" id="id23"><tt class="docutils literal"><span class="pre">yas/key-syntaxes</span></tt></a></li>
</ul>
</li>
</ul>
</div>
<div class="section" id="triggering-expansion">
<h1><a class="toc-backref" href="#id2">Triggering expansion</a></h1>
<p>You can use YASnippet to expand snippets in different ways:</p>
<ul class="simple">
<li>By typing an abbrev, the snippet <em>trigger key</em>, and then pressing
the key defined in <tt class="docutils literal"><span class="pre">yas/trigger-key</span></tt> (which defaults to
"TAB"). This works in buffers where the minor mode
<tt class="docutils literal"><span class="pre">yas/minor-mode</span></tt> is active;</li>
<li>By invoking the command <tt class="docutils literal"><span class="pre">yas/insert-snippet</span></tt> (either by typing
<tt class="docutils literal"><span class="pre">M-x</span> <span class="pre">yas/insert-snippet</span></tt> or its keybinding). This does <em>not</em>
require <tt class="docutils literal"><span class="pre">yas/minor-mode</span></tt> to be active.</li>
<li>By using the keybinding associated with an active snippet. This also
requires <tt class="docutils literal"><span class="pre">yas/minor-mode</span></tt> to be active;</li>
<li>By expanding directly from the "YASnippet" menu in the menu-bar</li>
<li>By using hippie-expand</li>
<li>Expanding from emacs-lisp code</li>
</ul>
<div class="section" id="trigger-key">
<h2><a class="toc-backref" href="#id3">Trigger key</a></h2>
<p>When <tt class="docutils literal"><span class="pre">yas/minor-mode</span></tt> is enabled, the keybinding taken from
<tt class="docutils literal"><span class="pre">yas/trigger-key</span></tt> will take effect.</p>
<p><tt class="docutils literal"><span class="pre">yas/trigger-key</span></tt> invokes <tt class="docutils literal"><span class="pre">yas/expand</span></tt>, which tries to expand a
<em>snippet abbrev</em> (also known as <em>snippet key</em>) before point.</p>
<p>The default key is <tt class="docutils literal"><span class="pre">"TAB"</span></tt>, however, you can freely set it to some
other key.</p>
<img align="left" alt="images/minor-mode-indicator.png" class="align-left" src="images/minor-mode-indicator.png" />
<p>To enable the YASnippet minor mode in all buffers globally use the
command <tt class="docutils literal"><span class="pre">yas/global-mode</span></tt>.</p>
<p>When you use <tt class="docutils literal"><span class="pre">yas/global-mode</span></tt> you can also selectively disable
YASnippet in some buffers by setting the buffer-local variable
<tt class="docutils literal"><span class="pre">yas/dont-active</span></tt> in the buffer's mode hook.</p>
<p>Trouble when using or understanding the <tt class="docutils literal"><span class="pre">yas/trigger-key</span></tt> is easily
the most controversial issue in YASsnippet. See the <a class="reference external" href="faq.html">FAQ</a>.</p>
<div class="section" id="fallback-bahaviour">
<h3><a class="toc-backref" href="#id4">Fallback bahaviour</a></h3>
<p><tt class="docutils literal"><span class="pre">yas/fallback-behaviour</span></tt> is a customization variable bound to
<tt class="docutils literal"><span class="pre">'call-other-command</span></tt> by default. If <tt class="docutils literal"><span class="pre">yas/expand</span></tt> failed to find
any suitable snippet to expand, it will disable the minor mode
temporarily and find if there's any other command bound the
<tt class="docutils literal"><span class="pre">yas/trigger-key</span></tt>.</p>
<p>If found, the command will be called. Usually this works very well --
when there's a snippet, expand it, otherwise, call whatever command
originally bind to the trigger key.</p>
<p>However, you can change this behavior by customizing the
<tt class="docutils literal"><span class="pre">yas/fallback-behavior</span></tt> variable. If you set this variable to
<tt class="docutils literal"><span class="pre">'return-nil</span></tt>, it will return <tt class="docutils literal"><span class="pre">nil</span></tt> instead of trying to call the
<em>original</em> command when no snippet is found.</p>
</div>
</div>
<div class="section" id="insert-at-point">
<h2><a class="toc-backref" href="#id5">Insert at point</a></h2>
<p>The command <tt class="docutils literal"><span class="pre">M-x</span> <span class="pre">yas/insert-snippet</span></tt> lets you insert snippets at
point <em>for you current major mode</em>. It prompts you for the snippet
key first, and then for a snippet template if more than one template
exists for the same key.</p>
<p>The list presented contains the snippets that can be inserted at
point, according to the condition system. If you want to see all
applicable snippets for the major mode, prefix this command with
<tt class="docutils literal"><span class="pre">C-u</span></tt>.</p>
<p>The prompting methods used are again controlled by
<tt class="docutils literal"><span class="pre">yas/prompt-functions</span></tt>.</p>
</div>
<div class="section" id="snippet-keybinding">
<h2><a class="toc-backref" href="#id6">Snippet keybinding</a></h2>
<p>See the section of the <tt class="docutils literal"><span class="pre">#</span> <span class="pre">binding:</span></tt> directive in <a class="reference external" href="snippet-development.html">Writing
Snippets</a>.</p>
</div>
<div class="section" id="expanding-from-the-menu">
<h2><a class="toc-backref" href="#id7">Expanding from the menu</a></h2>
<p>See <a class="reference external" href="snippet-menu.html">the YASnippet Menu</a>.</p>
</div>
<div class="section" id="expanding-with-hippie-expand">
<h2><a class="toc-backref" href="#id8">Expanding with <tt class="docutils literal"><span class="pre">hippie-expand</span></tt></a></h2>
<p>To integrate with <tt class="docutils literal"><span class="pre">hippie-expand</span></tt>, just put
<tt class="docutils literal"><span class="pre">yas/hippie-try-expand</span></tt> in
<tt class="docutils literal"><span class="pre">hippie-expand-try-functions-list</span></tt>. This probably makes more sense
when placed at the top of the list, but it can be put anywhere you
prefer.</p>
</div>
<div class="section" id="expanding-from-emacs-lisp-code">
<h2><a class="toc-backref" href="#id9">Expanding from emacs-lisp code</a></h2>
<p>Sometimes you might want to expand a snippet directly from you own
elisp code. You should call <tt class="docutils literal"><span class="pre">yas/expand-snippet</span></tt> instead of
<tt class="docutils literal"><span class="pre">yas/expand</span></tt> in this case.</p>
<p>As with expanding from the menubar, the condition system and multiple
candidates doesn't affect expansion. In fact, expanding from the
YASnippet menu has the same effect of evaluating the follow code:</p>
<div class="highlight"><pre>(<span style="color: #19177C">yas/expand-snippet</span> <span style="color: #19177C">template</span>)
</pre></div>
<p>See the internal documentation on <tt class="docutils literal"><span class="pre">yas/expand-snippet</span></tt> for more
information.</p>
</div>
</div>
<div class="section" id="controlling-expansion">
<h1><a class="toc-backref" href="#id10">Controlling expansion</a></h1>
<div class="section" id="eligible-snippets">
<h2><a class="toc-backref" href="#id11">Eligible snippets</a></h2>
<p>YASnippet does quite a bit of filtering to find out which snippets are
eligible for expanding at the current cursor position.</p>
<p>In particular, the following things matter:</p>
<ul>
<li><p class="first">Currently loaded snippets tables</p>
<p>These are loaded from a directory hierarchy in your file system. See
<a class="reference external" href="snippet-organization.html">Organizing Snippets</a>. They are named after major modes like
<tt class="docutils literal"><span class="pre">html-mode</span></tt>, <tt class="docutils literal"><span class="pre">ruby-mode</span></tt>, etc...</p>
</li>
<li><p class="first">Major mode of the current buffer</p>
<p>If the currrent major mode matches one of the loaded snippet tables,
then all that table's snippets are considered for expansion. Use
<tt class="docutils literal"><span class="pre">M-x</span> <span class="pre">describe-variable</span> <span class="pre">RET</span> <span class="pre">major-mode</span> <span class="pre">RET</span></tt> to find out which major
mode you are in currently.</p>
</li>
<li><p class="first">Parent tables</p>
<p>Snippet tables defined as the parent of some other eligible table
are also considered. This works recursively, i.e. parents of parents
of eligible tables are also considered.</p>
</li>
<li><p class="first">Buffer-local <tt class="docutils literal"><span class="pre">yas/mode-symbol</span></tt> variable</p>
<p>This can be used to consider snippet tables whose name does not
correspond to a major mode. If you set this variable to a name ,
like <tt class="docutils literal"><span class="pre">rinari-minor-mode</span></tt>, you can have some snippets expand only
in that minor mode. Naturally, you want to set this conditionally,
i.e. only when entering that minor mode, so using a hook is a good
idea.</p>
</li>
</ul>
<div class="highlight"><pre><span style="color: #408080; font-style: italic">;; When entering rinari-minor-mode, consider also the snippets in the</span>
<span style="color: #408080; font-style: italic">;; snippet table "rails-mode"</span>
(<span style="color: #19177C">add-hook</span> <span style="color: #19177C">'rinari-minor-mode-hook</span>
<span style="color: #0000FF">#'</span>(<span style="color: #008000; font-weight: bold">lambda</span> ()
(<span style="color: #008000; font-weight: bold">setq</span> <span style="color: #19177C">yas/mode-symbol</span> <span style="color: #19177C">'rails-mode</span>)))
</pre></div>
<ul>
<li><p class="first">Buffer-local <tt class="docutils literal"><span class="pre">yas/buffer-local-condition</span></tt> variable</p>
<p>This variable provides finer grained control over what snippets can
be expanded in the current buffer. The default value won't let you
expand snippets inside comments or string literals for example. See
<a class="reference internal" href="#the-condition-system">The condition system</a> for more info.</p>
</li>
</ul>
</div>
<div class="section" id="the-condition-system">
<h2><a class="toc-backref" href="#id12">The condition system</a></h2>
<p>Consider this scenario: you are an old Emacs hacker. You like the
abbrev-way and set <tt class="docutils literal"><span class="pre">yas/trigger-key</span></tt> to <tt class="docutils literal"><span class="pre">"SPC"</span></tt>. However,
you don't want <tt class="docutils literal"><span class="pre">if</span></tt> to be expanded as a snippet when you are typing
in a comment block or a string (e.g. in <tt class="docutils literal"><span class="pre">python-mode</span></tt>).</p>
<p>If you use the <tt class="docutils literal"><span class="pre">#</span> <span class="pre">condition</span> <span class="pre">:</span></tt> directive (see <a class="reference external" href="snippet-development.html">Writing Snippets</a>)
you could just specify the condition for <tt class="docutils literal"><span class="pre">if</span></tt> to be <tt class="docutils literal"><span class="pre">(not</span>
<span class="pre">(python-in-string/comment))</span></tt>. But how about <tt class="docutils literal"><span class="pre">while</span></tt>, <tt class="docutils literal"><span class="pre">for</span></tt>,
etc. ? Writing the same condition for all the snippets is just
boring. So has a buffer local variable
<tt class="docutils literal"><span class="pre">yas/buffer-local-condition</span></tt>. You can set this variable to <tt class="docutils literal"><span class="pre">(not</span>
<span class="pre">(python-in-string/comment))</span></tt> in <tt class="docutils literal"><span class="pre">python-mode-hook</span></tt>.</p>
<p>Then, what if you really want some particular snippet to expand even
inside a comment? This is also possible! But let's stop telling the
story and look at the rules:</p>
<ul class="simple">
<li>If <tt class="docutils literal"><span class="pre">yas/buffer-local-condition</span></tt> evaluate to nil, no snippets will
be considered for expansion.</li>
<li>If it evaluates to the a <em>cons cell</em> where the <tt class="docutils literal"><span class="pre">car</span></tt> is the symbol
<tt class="docutils literal"><span class="pre">require-snippet-condition</span></tt> and the <tt class="docutils literal"><span class="pre">cdr</span></tt> is a symbol (let's
call it <tt class="docutils literal"><span class="pre">requirement</span></tt>), then:<ul>
<li>Snippets having no <tt class="docutils literal"><span class="pre">#</span> <span class="pre">condition:</span></tt> directive won't be considered;</li>
<li>Snippets with conditions that evaluate to nil (or produce an
error) won't be considered;</li>
<li>If the snippet has a condition that evaluates to non-nil (let's
call it <tt class="docutils literal"><span class="pre">result</span></tt>):<ul>
<li>If <tt class="docutils literal"><span class="pre">requirement</span></tt> is <tt class="docutils literal"><span class="pre">t</span></tt>, the snippet is ready to be
expanded;</li>
<li>If <tt class="docutils literal"><span class="pre">requirement</span></tt> is <tt class="docutils literal"><span class="pre">eq</span></tt> to <tt class="docutils literal"><span class="pre">result</span></tt>, the snippet is ready
to be expanded;</li>
<li>Otherwise the snippet won't be considered.</li>
</ul>
</li>
</ul>
</li>
<li>If it evaluates to the symbol <tt class="docutils literal"><span class="pre">always</span></tt>, all snippets are
considered for expansion, regardless of any conditions.</li>
<li>If it evaluate to <tt class="docutils literal"><span class="pre">t</span></tt> or some other non-nil value:<ul>
<li>If the snippet has no condition, or has a condition that evaluate
to non-nil, it is ready to be expanded.</li>
<li>Otherwise, it won't be considered.</li>
</ul>
</li>
</ul>
<p>In the mentioned scenario, set <tt class="docutils literal"><span class="pre">yas/buffer-local-condition</span></tt> like
this</p>
<div class="highlight"><pre>(<span style="color: #19177C">add-hook</span> <span style="color: #19177C">'python-mode-hook</span>
<span style="color: #666666">'</span>(<span style="color: #008000; font-weight: bold">lambda</span> ()
(<span style="color: #008000; font-weight: bold">setq</span> <span style="color: #19177C">yas/buffer-local-condition</span>
<span style="color: #666666">'</span>(<span style="color: #008000; font-weight: bold">if</span> (<span style="color: #19177C">python-in-string/comment</span>)
<span style="color: #666666">'</span>(<span style="color: #19177C">require-snippet-condition</span> <span style="color: #666666">.</span> <span style="color: #19177C">force-in-comment</span>)
<span style="color: #880000">t</span>))))
</pre></div>
<p>... and specify the condition for a snippet that you're going to
expand in comment to be evaluated to the symbol
<tt class="docutils literal"><span class="pre">force-in-comment</span></tt>. Then it can be expanded as you expected, while
other snippets like <tt class="docutils literal"><span class="pre">if</span></tt> still can't expanded in comment.</p>
</div>
<div class="section" id="multiples-snippet-with-the-same-key">
<h2><a class="toc-backref" href="#id13">Multiples snippet with the same key</a></h2>
<p>The rules outlined <a class="reference external" href="Eligiblesnippets">above</a> can return more than
one snippet to be expanded at point.</p>
<p>When there are multiple candidates, YASnippet will let you select
one. The UI for selecting multiple candidate can be customized through
<tt class="docutils literal"><span class="pre">yas/prompt-functions</span></tt> , which defines your preferred methods of
being prompted for snippets.</p>
<p>You can customize it with <tt class="docutils literal"><span class="pre">M-x</span> <span class="pre">customize-variable</span> <span class="pre">RET</span>
<span class="pre">yas/prompt-functions</span> <span class="pre">RET</span></tt>. Alternatively you can put in your
emacs-file:</p>
<div class="highlight"><pre>(<span style="color: #008000; font-weight: bold">setq</span> <span style="color: #19177C">yas/prompt-functions</span> <span style="color: #666666">'</span>(<span style="color: #19177C">yas/x-prompt</span> <span style="color: #19177C">yas/dropdown-prompt</span>))
</pre></div>
<p>Currently there are some alternatives solution with YASnippet.</p>
<img align="right" alt="images/x-menu.png" class="align-right" src="images/x-menu.png" />
<div class="section" id="use-the-x-window-system">
<h3><a class="toc-backref" href="#id14">Use the X window system</a></h3>
<p>The function <tt class="docutils literal"><span class="pre">yas/x-prompt</span></tt> can be used to show a popup menu for you
to select. This menu will be part of you native window system widget,
which means:</p>
<ul class="simple">
<li>It usually looks beautiful. E.g. when you compile Emacs with gtk
support, this menu will be rendered with your gtk theme.</li>
<li>Emacs have little control over it. E.g. you can't use <tt class="docutils literal"><span class="pre">C-n</span></tt>,
<tt class="docutils literal"><span class="pre">C-p</span></tt> to navigate.</li>
<li>This function can't be used when in a terminal.</li>
</ul>
<img align="right" alt="images/ido-menu.png" class="align-right" src="images/ido-menu.png" />
</div>
<div class="section" id="minibuffer-prompting">
<h3><a class="toc-backref" href="#id15">Minibuffer prompting</a></h3>
<p>You can use functions <tt class="docutils literal"><span class="pre">yas/completing-prompt</span></tt> for the classic emacs
completion method or <tt class="docutils literal"><span class="pre">yas/ido-prompt</span></tt> for a much nicer looking
method. The best way is to try it. This works in a terminal.</p>
<img align="right" alt="images/dropdown-menu.png" class="align-right" src="images/dropdown-menu.png" />
</div>
<div class="section" id="use-dropdown-menu-el">
<h3><a class="toc-backref" href="#id16">Use <tt class="docutils literal"><span class="pre">dropdown-menu.el</span></tt></a></h3>
<p>The function <tt class="docutils literal"><span class="pre">yas/dropdown-prompt</span></tt> can also be placed in the
<tt class="docutils literal"><span class="pre">yas/prompt-functions</span></tt> list.</p>
<p>This works in both window system and terminal and is customizable, you
can use <tt class="docutils literal"><span class="pre">C-n</span></tt>, <tt class="docutils literal"><span class="pre">C-p</span></tt> to navigate, <tt class="docutils literal"><span class="pre">q</span></tt> to quit and even press
<tt class="docutils literal"><span class="pre">6</span></tt> as a shortcut to select the 6th candidate.</p>
</div>
<div class="section" id="roll-your-own">
<h3><a class="toc-backref" href="#id17">Roll your own</a></h3>
<p>See below for the documentation on variable <tt class="docutils literal"><span class="pre">yas/prompt-functions</span></tt></p>
</div>
</div>
</div>
<div class="section" id="customizable-variables">
<h1><a class="toc-backref" href="#id18">Customizable Variables</a></h1>
<div class="section" id="yas-prompt-functions">
<h2><a class="toc-backref" href="#id19"><tt class="docutils literal"><span class="pre">yas/prompt-functions</span></tt></a></h2>
<p>You can write a function and add it to the <tt class="docutils literal"><span class="pre">yas/prompt-functions</span></tt>
list. These functions are called with the following arguments:</p>
<ul class="simple">
<li>PROMPT: A string to prompt the user;</li>
<li>CHOICES: A list of strings or objects;</li>
<li>optional DISPLAY-FN : A function. When applied to each of the
objects in CHOICES it will return a string;</li>
</ul>
<p>The return value of any function you put here should be one of
the objects in CHOICES, properly formatted with DISPLAY-FN (if
that is passed).</p>
<ul class="simple">
<li>To signal that your particular style of prompting is unavailable at
the moment, you can also have the function return nil.</li>
<li>To signal that the user quit the prompting process, you can signal
<tt class="docutils literal"><span class="pre">quit</span></tt> with <tt class="docutils literal"><span class="pre">(signal</span> <span class="pre">'quit</span> <span class="pre">"user</span> <span class="pre">quit!")</span></tt></li>
</ul>
</div>
<div class="section" id="yas-fallback-behavior">
<h2><a class="toc-backref" href="#id20"><tt class="docutils literal"><span class="pre">yas/fallback-behavior</span></tt></a></h2>
<p>How to act when <tt class="docutils literal"><span class="pre">yas/expand</span></tt> does <em>not</em> expand a snippet.</p>
<dl class="docutils">
<dt><tt class="docutils literal"><span class="pre">call-other-command</span></tt> means try to temporarily disable YASnippet and</dt>
<dd>call the next command bound to <tt class="docutils literal"><span class="pre">yas/trigger-key</span></tt>.</dd>
</dl>
<p><tt class="docutils literal"><span class="pre">return-nil</span></tt> means return nil. (i.e. do nothing)</p>
<p>An entry (apply COMMAND . ARGS) means interactively call COMMAND, if
ARGS is non-nil, call COMMAND non-interactively with ARGS as
arguments.</p>
</div>
<div class="section" id="yas-choose-keys-first">
<h2><a class="toc-backref" href="#id21"><tt class="docutils literal"><span class="pre">yas/choose-keys-first</span></tt></a></h2>
<p>If non-nil, prompt for snippet key first, then for template.</p>
<p>Otherwise prompts for all possible snippet names.</p>
<p>This affects <tt class="docutils literal"><span class="pre">yas/insert-snippet</span></tt> and <tt class="docutils literal"><span class="pre">yas/visit-snippet-file</span></tt>.</p>
</div>
<div class="section" id="yas-choose-tables-first">
<h2><a class="toc-backref" href="#id22"><tt class="docutils literal"><span class="pre">yas/choose-tables-first</span></tt></a></h2>
<p>If non-nil, and multiple eligible snippet tables, prompts user for
tables first.</p>
<p>Otherwise, user chooses between the merging together of all
eligible tables.</p>
<p>This affects <tt class="docutils literal"><span class="pre">yas/insert-snippet</span></tt>, <tt class="docutils literal"><span class="pre">yas/visit-snippet-file</span></tt></p>
</div>
<div class="section" id="yas-key-syntaxes">
<h2><a class="toc-backref" href="#id23"><tt class="docutils literal"><span class="pre">yas/key-syntaxes</span></tt></a></h2>
<p>The default searching strategy is quite powerful. For example, in
<tt class="docutils literal"><span class="pre">c-mode</span></tt>, <tt class="docutils literal"><span class="pre">bar</span></tt>, <tt class="docutils literal"><span class="pre">foo_bar</span></tt>, <tt class="docutils literal"><span class="pre">"#foo_bar"</span></tt> can all be recognized
as a snippet key. Furthermore, the searching is in that order. In
other words, if <tt class="docutils literal"><span class="pre">bar</span></tt> is found to be a key to some <em>valid</em> snippet,
then that snippet is expanded and replaces the <tt class="docutils literal"><span class="pre">bar</span></tt>. Snippets
pointed to by <tt class="docutils literal"><span class="pre">foo_bar</span></tt> and <tt class="docutils literal"><span class="pre">"#foobar</span></tt> won't be considered.</p>
<p>However, this strategy can also be customized easily from the
<tt class="docutils literal"><span class="pre">yas/key-syntaxes</span></tt> variable. It is a list of syntax rules, the
default value is <tt class="docutils literal"><span class="pre">("w"</span> <span class="pre">"w_"</span> <span class="pre">"w_."</span> <span class="pre">"^</span> <span class="pre">")</span></tt>. Which means search the
following thing until found one:</p>
<ul class="simple">
<li>a word.</li>
<li>a symbol. In lisp, <tt class="docutils literal"><span class="pre">-</span></tt> and <tt class="docutils literal"><span class="pre">?</span></tt> can all be part of a symbol.</li>
<li>a sequence of characters of either word, symbol or punctuation.</li>
<li>a sequence of characters of non-whitespace characters.</li>
</ul>
<p>But you'd better keep the default value unless you want to understand
how Emacs's syntax rules work...</p>
</div>
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