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diff --git a/doc/groff.html.node/Delimiters.html b/doc/groff.html.node/Delimiters.html new file mode 100644 index 0000000..fa117db --- /dev/null +++ b/doc/groff.html.node/Delimiters.html @@ -0,0 +1,233 @@ +<!DOCTYPE html> +<html> +<!-- Created by GNU Texinfo 7.0.3, https://www.gnu.org/software/texinfo/ --> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> +<!-- This manual documents GNU troff version 1.23.0. + +Copyright © 1994-2023 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with no +Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A +copy of the license is included in the section entitled "GNU Free +Documentation License". --> +<title>Delimiters (The GNU Troff Manual)</title> + +<meta name="description" content="Delimiters (The GNU Troff Manual)"> +<meta name="keywords" content="Delimiters (The GNU Troff Manual)"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta name="viewport" content="width=device-width,initial-scale=1"> + +<link href="index.html" rel="start" title="Top"> +<link href="Request-Index.html" rel="index" title="Request Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="Formatter-Instructions.html" rel="up" title="Formatter Instructions"> +<link href="Using-Escape-Sequences.html" rel="prev" title="Using Escape Sequences"> +<style type="text/css"> +<!-- +div.example {margin-left: 3.2em} +kbd.key {font-style: normal} +ul.mark-bullet {list-style-type: disc} +--> +</style> + + +</head> + +<body lang="en"> +<div class="subsection-level-extent" id="Delimiters"> +<div class="nav-panel"> +<p> +Previous: <a href="Using-Escape-Sequences.html" accesskey="p" rel="prev">Using Escape Sequences</a>, Up: <a href="Formatter-Instructions.html" accesskey="u" rel="up">Formatter Instructions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Request-Index.html" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<h4 class="subsection" id="Delimiters-1">5.6.5 Delimiters</h4> +<a class="index-entry-id" id="index-delimiting-escape-sequence-arguments"></a> +<a class="index-entry-id" id="index-escape-sequence-argument-delimiters"></a> +<a class="index-entry-id" id="index-delimiters_002c-for-escape-sequence-arguments"></a> +<a class="index-entry-id" id="index-arguments_002c-to-escape-sequences_002c-delimiting"></a> + +<a class="index-entry-id" id="index-_0027_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_0022_002c-as-delimiter"></a> +<p>Some escape sequences that require parameters use delimiters. The +neutral apostrophe <code class="code">'</code> is a popular choice and shown in this +document. The neutral double quote <code class="code">"</code> is also commonly seen. +Letters, numerals, and leaders can be used. Punctuation characters +are likely better choices, except for those defined as infix operators +in numeric expressions; see below. +</p> +<div class="example"> +<div class="group"><pre class="example-preformatted">\l'1.5i\[bu]' \" draw 1.5 inches of bullet glyphs +</pre></div></div> + +<a class="index-entry-id" id="index-_005c_0025_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005cSP_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_007c_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_005e_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_007b_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_007d_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_0027_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_0060_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_002d_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_005f_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_0021_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_003f_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_0029_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_002f_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_002c_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_0026_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_003a_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c_007e_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005c0_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005ca_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005cc_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005cd_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005ce_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005cE_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005cp_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005cr_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005ct_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_005cu_002c-as-delimiter"></a> +<p>The following escape sequences don’t take arguments and thus are allowed +as delimiters: +<code class="code">\<kbd class="key">SP</kbd></code>, <code class="code">\%</code>, <code class="code">\|</code>, <code class="code">\^</code>, <code class="code">\{</code>, +<code class="code">\}</code>, <code class="code">\'</code>, <code class="code">\`</code>, <code class="code">\-</code>, <code class="code">\_</code>, <code class="code">\!</code>, +<code class="code">\?</code>, <code class="code">\)</code>, <code class="code">\/</code>, <code class="code">\,</code>, <code class="code">\&</code>, <code class="code">\:</code>, +<code class="code">\~</code>, <code class="code">\0</code>, <code class="code">\a</code>, <code class="code">\c</code>, <code class="code">\d</code>, <code class="code">\e</code>, +<code class="code">\E</code>, <code class="code">\p</code>, <code class="code">\r</code>, <code class="code">\t</code>, and <code class="code">\u</code>. However, +using them this way is discouraged; they can make the input confusing to +read. +</p> +<a class="index-entry-id" id="index-_005cA_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cb_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005co_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cw_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cX_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cZ_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-newline_002c-as-delimiter"></a> +<p>A few escape sequences, +<code class="code">\A</code>, +<code class="code">\b</code>, +<code class="code">\o</code>, +<code class="code">\w</code>, +<code class="code">\X</code>, +and <code class="code">\Z</code>, accept a newline as a delimiter. Newlines that serve +as delimiters continue to be recognized as input line terminators. +</p> +<div class="example"> +<div class="group"><pre class="example-preformatted">A caf\o +e\(aa +in Paris + ⇒ A café in Paris +</pre></div></div> + +<p>Use of newlines as delimiters in escape sequences is also discouraged. +</p> +<a class="index-entry-id" id="index-_005cD_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005ch_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cH_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cl_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cL_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cN_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cR_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cs_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cS_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cv_002c-delimiters-allowed-by"></a> +<a class="index-entry-id" id="index-_005cx_002c-delimiters-allowed-by"></a> +<p>Finally, the escape sequences <code class="code">\D</code>, <code class="code">\h</code>, <code class="code">\H</code>, +<code class="code">\l</code>, <code class="code">\L</code>, <code class="code">\N</code>, <code class="code">\R</code>, <code class="code">\s</code>, <code class="code">\S</code>, +<code class="code">\v</code>, and <code class="code">\x</code> prohibit many delimiters. +</p> +<ul class="itemize mark-bullet"> +<li><a class="index-entry-id" id="index-numerals_002c-as-delimiters"></a> +<a class="index-entry-id" id="index-digits_002c-as-delimiters"></a> +<a class="index-entry-id" id="index-_002e_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-decimal-point_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-dot_002c-as-delimiter"></a> +the numerals <code class="code">0</code>-<code class="code">9</code> and the decimal point <code class="code">.</code> + +</li><li><a class="index-entry-id" id="index-operators_002c-as-delimiters"></a> +<a class="index-entry-id" id="index-_002b_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_002d_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_002f_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_002a_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_0025_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_003c_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_003e_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_003d_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_0026_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_003a_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_0028_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-_0029_002c-as-delimiter"></a> +the (single-character) operators ‘<samp class="samp">+-/*%<>=&:()</samp>’ + +</li><li><a class="index-entry-id" id="index-space-character_002c-as-delimiter"></a> +<a class="index-entry-id" id="index-tab-character_002c-as-delimiter"></a> +the space and tab characters + +</li><li><a class="index-entry-id" id="index-_005c_0025_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005c_003a_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005c_007b_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005c_007d_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005c_0027_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005c_0060_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005c_002d_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005c_005f_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005c_0021_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005c_002f_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005cc_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005ce_002c-as-delimiter-1"></a> +<a class="index-entry-id" id="index-_005cp_002c-as-delimiter-1"></a> +any escape sequences other than <code class="code">\%</code>, <code class="code">\:</code>, <code class="code">\{</code>, +<code class="code">\}</code>, <code class="code">\'</code>, <code class="code">\`</code>, <code class="code">\-</code>, <code class="code">\_</code>, <code class="code">\!</code>, +<code class="code">\/</code>, <code class="code">\c</code>, <code class="code">\e</code>, and <code class="code">\p</code> +</li></ul> + +<p>Delimiter syntax is complex and flexible primarily for historical +reasons; the foregoing restrictions need be kept in mind mainly when +using <code class="code">groff</code> in <abbr class="acronym">AT&T</abbr> compatibility mode. GNU +<code class="code">troff</code> keeps track of the nesting depth of escape sequence +interpolations, so the only characters you need to avoid using as +delimiters are those that appear in the arguments you input, not any +that result from interpolation. Typically, <code class="code">'</code> works fine. +See <a class="xref" href="Implementation-Differences.html">Implementation Differences</a>. +</p> +<div class="example"> +<div class="group"><pre class="example-preformatted">$ groff -Tps +.de Mw +. nr wd \w'\\$1' +. tm "\\$1" is \\n(wd units wide. +.. +.Mw Wet'suwet'en +.Mw Wet+200i +.cp 1 \" turn on compatibility mode +.Mw Wet'suwet'en +.Mw Wet' +.Mw Wet+200i + error→ "Wet'suwet'en" is 54740 units wide. + error→ "Wet'+200i" is 42610 units wide. + error→ "Wet'suwet'en" is 15860 units wide. + error→ "Wet'" is 15860 units wide. + error→ "Wet'+200i" is 14415860 units wide. +</pre></div></div> + +<p>We see here that in compatibility mode, the part of the argument after +the <code class="code">'</code> delimiter escapes from its context and, if nefariously +crafted, influences the computation of the <var class="var">wd</var> register’s value in +a surprising way. +</p> +</div> +<hr> +<div class="nav-panel"> +<p> +Previous: <a href="Using-Escape-Sequences.html">Using Escape Sequences</a>, Up: <a href="Formatter-Instructions.html">Formatter Instructions</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Request-Index.html" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |