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<title>Comments (The GNU Troff Manual)</title>
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<h3 class="section" id="Comments-1">5.7 Comments</h3>
<a class="index-entry-id" id="index-comments"></a>
<p>One of the most common forms of escape sequence is the
comment.<a class="footnote" id="DOCF48" href="groff.html_fot.html#FOOT48"><sup>48</sup></a>
</p>
<dl class="first-deffn">
<dt class="deffn" id="index-_005c_0022-1"><span class="category-def">Escape sequence: </span><span><strong class="def-name"><code class="t">\"</code><span class="r"><i class="slanted"></i></span><code class="t"></code></strong><a class="copiable-link" href='#index-_005c_0022-1'> ¶</a></span></dt>
<dd><a class="index-entry-id" id="index-_005c_0022"></a>
<p>Start a comment. Everything up to the next newline is ignored.
</p>
<p>This may sound simple, but it can be tricky to keep the comments from
interfering with the appearance of the output.
<a class="index-entry-id" id="index-ds_002c-ds1-requests_002c-and-comments"></a>
<a class="index-entry-id" id="index-as_002c-as1-requests_002c-and-comments"></a>
If the escape sequence is to the right of some text or a request, that
portion of the line is ignored, but spaces preceding it are processed
normally by GNU <code class="code">troff</code>. This affects only the <code class="code">ds</code> and
<code class="code">as</code> requests and their variants.
</p>
<a class="index-entry-id" id="index-tabs_002c-before-comments"></a>
<a class="index-entry-id" id="index-comments_002c-lining-up-with-tabs"></a>
<p>One possibly irritating idiosyncrasy is that tabs should not be used to
vertically align comments in the source document. Tab characters are
not treated as separators between a request name and its first argument,
nor between arguments.
</p>
<a class="index-entry-id" id="index-undefined-request"></a>
<a class="index-entry-id" id="index-request_002c-undefined"></a>
<p>A comment on a line by itself is treated as a blank line, because after
eliminating the comment, that is all that remains.
</p>
<div class="example">
<div class="group"><pre class="example-preformatted">Test
\" comment
Test
⇒ Test
⇒
⇒ Test
</pre></div></div>
<p>To avoid this, it is common to combine the empty request with the
comment escape sequence as ‘<samp class="samp">.\"</samp>’, causing the input line to be
ignored.
</p>
<a class="index-entry-id" id="index-_0027_002c-as-a-comment"></a>
<p>Another commenting scheme sometimes seen is three consecutive single
quotes (<code class="code">'''</code>) at the beginning of a line. This works, but GNU
<code class="code">troff</code> emits a warning diagnostic (if enabled) about an undefined
macro (namely ‘<samp class="samp">''</samp>’).
</p></dd></dl>
<dl class="first-deffn">
<dt class="deffn" id="index-_005c_0023-1"><span class="category-def">Escape sequence: </span><span><strong class="def-name"><code class="t">\#</code><span class="r"><i class="slanted"></i></span><code class="t"></code></strong><a class="copiable-link" href='#index-_005c_0023-1'> ¶</a></span></dt>
<dd><a class="index-entry-id" id="index-_005c_0023"></a>
<p>Start a comment; everything up to and including the next newline is
ignored. This <code class="code">groff</code> extension was introduced to avoid the
problems described above.
</p>
<div class="example">
<div class="group"><pre class="example-preformatted">Test
\# comment
Test
⇒ Test Test
</pre></div></div>
</dd></dl>
<dl class="first-deffn">
<dt class="deffn" id="index-_002eig"><span class="category-def">Request: </span><span><strong class="def-name"><code class="t">.ig</code></strong> <var class="def-var-arguments">[<span class="r"><i class="slanted">end</i></span>]</var><a class="copiable-link" href='#index-_002eig'> ¶</a></span></dt>
<dd><a class="index-entry-id" id="index-ig"></a>
<p>Ignore input until, in the current conditional block (if
any),<a class="footnote" id="DOCF49" href="groff.html_fot.html#FOOT49"><sup>49</sup></a> the macro <var class="var">end</var> is called
at the start of a control line, or the control line ‘<samp class="samp">..</samp>’ is
encountered if <var class="var">end</var> is not specified. <code class="code">ig</code> is parsed as if it
were a macro definition, but its contents are discarded, not
stored.<a class="footnote" id="DOCF50" href="groff.html_fot.html#FOOT50"><sup>50</sup></a>
</p>
<div class="example">
<div class="group"><pre class="example-preformatted">hand\c
.de TX
fasting
..
.ig TX
This is part of a large block of input that has been
temporarily(?) commented out.
We can restore it simply by removing the .ig request and
the call of its end macro.
.TX
</pre></div></div>
<div class="example">
<div class="group"><pre class="example-preformatted"> ⇒ handfasting
</pre></div></div>
</dd></dl>
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