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diff --git a/doc/groff.html.node/Environments.html b/doc/groff.html.node/Environments.html new file mode 100644 index 0000000..489ee62 --- /dev/null +++ b/doc/groff.html.node/Environments.html @@ -0,0 +1,250 @@ +<!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>Environments (The GNU Troff Manual)</title> + +<meta name="description" content="Environments (The GNU Troff Manual)"> +<meta name="keywords" content="Environments (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="GNU-troff-Reference.html" rel="up" title="GNU troff Reference"> +<link href="Suppressing-Output.html" rel="next" title="Suppressing Output"> +<link href="Diversions.html" rel="prev" title="Diversions"> +<style type="text/css"> +<!-- +a.copiable-link {visibility: hidden; text-decoration: none; line-height: 0em} +div.example {margin-left: 3.2em} +span.r {font-family: initial; font-weight: normal; font-style: normal} +span:hover a.copiable-link {visibility: visible} +strong.def-name {font-family: monospace; font-weight: bold; font-size: larger} +ul.mark-bullet {list-style-type: disc} +--> +</style> + + +</head> + +<body lang="en"> +<div class="section-level-extent" id="Environments"> +<div class="nav-panel"> +<p> +Next: <a href="Suppressing-Output.html" accesskey="n" rel="next">Suppressing Output</a>, Previous: <a href="Diversions.html" accesskey="p" rel="prev">Diversions</a>, Up: <a href="GNU-troff-Reference.html" accesskey="u" rel="up">GNU <code class="code">troff</code> Reference</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> +<h3 class="section" id="Environments-1">5.31 Environments</h3> +<a class="index-entry-id" id="index-environments"></a> + +<p>As discussed in <a class="ref" href="Deferring-Output.html">Deferring Output</a>, environments store most of the +parameters that determine the appearance of text. A default environment +named ‘<samp class="samp">0</samp>’ exists when GNU <code class="code">troff</code> starts up; it is modified by +formatting-related requests and escape sequences. +</p> +<a class="index-entry-id" id="index-stack"></a> +<p>You can create new environments and switch among them. Only one is +current at any given time. Active environments are managed using a +<em class="dfn">stack</em>, a data structure supporting “push” and “pop” +operations. The current environment is at the top of the stack. +The same environment name can be pushed onto the stack multiple times, +possibly interleaved with others. Popping the environment stack does +not destroy the current environment; it remains accessible by name and +can be made current again by pushing it at any time. Environments +cannot be renamed or deleted, and can only be modified when current. To +inspect the environment stack, use the <code class="code">pev</code> request; see +<a class="ref" href="Debugging.html">Debugging</a>. +</p> +<p>Environments store the following information. +</p> +<ul class="itemize mark-bullet"> +<li>a partially collected line, if any + +</li><li>data about the most recently output glyph and line (registers +<code class="code">.cdp</code>, <code class="code">.cht</code>, <code class="code">.csk</code>, <code class="code">.n</code>, <code class="code">.w</code>) + +</li><li>typeface parameters (size, family, style, height and slant, inter-word +and inter-sentence space sizes) + +</li><li>page parameters (line length, title length, vertical spacing, line +spacing, indentation, line numbering, centering, right-alignment, +underlining, hyphenation parameters) + +</li><li>filling enablement; adjustment enablement and mode + +</li><li>tab stops; tab, leader, escape, control, no-break control, hyphenation, +and margin characters + +</li><li>input line traps + +</li><li>stroke and fill colors +</li></ul> + +<dl class="first-deffn"> +<dt class="deffn" id="index-_002eev"><span class="category-def">Request: </span><span><strong class="def-name"><code class="t">.ev</code></strong> <var class="def-var-arguments">[<span class="r"><i class="slanted">ident</i></span>]</var><a class="copiable-link" href='#index-_002eev'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-ev"></a> +</dd><dt class="deffnx def-cmd-deffn" id="index-_005cn_005b_002eev_005d"><span class="category-def">Register: </span><span><strong class="def-name"><code class="t">\n[.ev]</code></strong><a class="copiable-link" href='#index-_005cn_005b_002eev_005d'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-_002eev-1"></a> +<a class="index-entry-id" id="index-switching-environments-_0028ev_0029"></a> +<a class="index-entry-id" id="index-environment_002c-switching-_0028ev_0029"></a> +<a class="index-entry-id" id="index-environment-number_002fname-register-_0028_002eev_0029"></a> +<p>Enter the environment <var class="var">ident</var>, which is created if it does not +already exist, using the same parameters as for the default environment +used at startup. With no argument, GNU <code class="code">troff</code> switches to the +previous environment. +</p> +<p>Invoking <code class="code">ev</code> with an argument puts environment <var class="var">ident</var> onto +the top of the environment stack. (If it isn’t already present in the +stack, this is a proper push.) Without an argument, <code class="code">ev</code> pops the +environment stack, making the previous environment current. It is an +error to pop the environment stack with no previous environment +available. The read-only string-valued register <code class="code">.ev</code> contains the +name of the current environment—the one at the top of the stack. +</p> +<div class="example"> +<div class="group"><pre class="example-preformatted">.ev footnote-env +.fam N +.ps 6 +.vs 8 +.ll -.5i +.ev + +<span class="r">…</span> + +.ev footnote-env +\[dg] Observe the smaller text and vertical spacing. +.ev +</pre></div></div> + +<p>We can familiarize ourselves with stack behavior by wrapping the +<code class="code">ev</code> request with a macro that reports the contents of the +<code class="code">.ev</code> register to the standard error stream. +</p> +<div class="example"> +<div class="group"><pre class="example-preformatted">.de EV +. ev \\$1 +. tm environment is now \\n[.ev] +.. +. +.EV foo +.EV bar +.EV +.EV baz +.EV +.EV +.EV +</pre></div></div> + +<div class="example"> +<div class="group"><pre class="example-preformatted"> error→ environment is now foo + error→ environment is now bar + error→ environment is now foo + error→ environment is now baz + error→ environment is now foo + error→ environment is now 0 + error→ error: environment stack underflow + error→ environment is now 0 +</pre></div></div> + +</dd></dl> + +<dl class="first-deffn"> +<dt class="deffn" id="index-_002eevc"><span class="category-def">Request: </span><span><strong class="def-name"><code class="t">.evc</code></strong> <var class="def-var-arguments">environment</var><a class="copiable-link" href='#index-_002eevc'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-evc"></a> +<a class="index-entry-id" id="index-copying-environment-_0028evc_0029"></a> +<a class="index-entry-id" id="index-environment_002c-copying-_0028evc_0029"></a> +<p>Copy the contents of <var class="var">environment</var> to the current environment. +</p> +<p>The following environment data are not copied. +</p> +<ul class="itemize mark-bullet"> +<li>a partially collected line, if present; + +</li><li>the interruption status of the previous input line (due to use of the +<code class="code">\c</code> escape sequence); + +</li><li>the count of remaining lines to center, to right-justify, or to +underline (with or without underlined spaces)—these are set to zero; + +</li><li>the activation status of temporary indentation; + +</li><li>input line traps and their associated data; + +</li><li>the activation status of line numbering (which can be reactivated with +‘<samp class="samp">.nm +0</samp>’<!-- /@w -->); and + +</li><li>the count of consecutive hyphenated lines (set to zero). +</li></ul> +</dd></dl> + +<dl class="first-deffn"> +<dt class="deffn" id="index-_005cn_005b_002ew_005d"><span class="category-def">Register: </span><span><strong class="def-name"><code class="t">\n[.w]</code></strong><a class="copiable-link" href='#index-_005cn_005b_002ew_005d'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-_002ew"></a> +</dd><dt class="deffnx def-cmd-deffn" id="index-_005cn_005b_002echt_005d"><span class="category-def">Register: </span><span><strong class="def-name"><code class="t">\n[.cht]</code></strong><a class="copiable-link" href='#index-_005cn_005b_002echt_005d'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-_002echt"></a> +</dd><dt class="deffnx def-cmd-deffn" id="index-_005cn_005b_002ecdp_005d"><span class="category-def">Register: </span><span><strong class="def-name"><code class="t">\n[.cdp]</code></strong><a class="copiable-link" href='#index-_005cn_005b_002ecdp_005d'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-_002ecdp"></a> +</dd><dt class="deffnx def-cmd-deffn" id="index-_005cn_005b_002ecsk_005d"><span class="category-def">Register: </span><span><strong class="def-name"><code class="t">\n[.csk]</code></strong><a class="copiable-link" href='#index-_005cn_005b_002ecsk_005d'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-_002ecsk"></a> +<a class="index-entry-id" id="index-environment_002c-dimensions-of-last-glyph-_0028_002ew_002c-_002echt_002c-_002ecdp_002c-_002ecsk_0029"></a> +<a class="index-entry-id" id="index-width_002c-of-last-glyph-_0028_002ew_0029"></a> +<a class="index-entry-id" id="index-height_002c-of-last-glyph-_0028_002echt_0029"></a> +<a class="index-entry-id" id="index-depth_002c-of-last-glyph-_0028_002ecdp_0029"></a> +<a class="index-entry-id" id="index-skew_002c-of-last-glyph-_0028_002ecsk_0029"></a> +<a class="index-entry-id" id="index-last-glyph_002c-dimensions-_0028_002ew_002c-_002echt_002c-_002ecdp_002c-_002ecsk_0029"></a> +<a class="index-entry-id" id="index-glyph_002c-last_002c-dimensions-_0028_002ew_002c-_002echt_002c-_002ecdp_002c-_002ecsk_0029"></a> +<p>The <code class="code">\n[.w]</code> register contains the width of the last glyph +formatted in the environment. +</p> +<p>The <code class="code">\n[.cht]</code> register contains the height of the last glyph +formatted in the environment. +</p> +<p>The <code class="code">\n[.cdp]</code> register contains the depth of the last glyph +formatted in the environment. It is positive for glyphs extending below +the baseline. +</p> +<p>The <code class="code">\n[.csk]</code> register contains the <em class="dfn">skew</em> (how far to the +right of the glyph’s center that GNU <code class="code">troff</code> should place an +accent) of the last glyph formatted in the environment. +</p></dd></dl> + +<dl class="first-deffn"> +<dt class="deffn" id="index-_005cn_005b_002en_005d"><span class="category-def">Register: </span><span><strong class="def-name"><code class="t">\n[.n]</code></strong><a class="copiable-link" href='#index-_005cn_005b_002en_005d'> ¶</a></span></dt> +<dd><a class="index-entry-id" id="index-_002en"></a> +<a class="index-entry-id" id="index-environment_002c-previous-line-length-_0028_002en_0029"></a> +<a class="index-entry-id" id="index-line-length_002c-previous-_0028_002en_0029"></a> +<a class="index-entry-id" id="index-length-of-previous-line-_0028_002en_0029"></a> +<a class="index-entry-id" id="index-previous-line-length-_0028_002en_0029"></a> +<p>The <code class="code">\n[.n]</code> register contains the length of the previous output +line emitted in the environment. +</p></dd></dl> + + + + +</div> +<hr> +<div class="nav-panel"> +<p> +Next: <a href="Suppressing-Output.html">Suppressing Output</a>, Previous: <a href="Diversions.html">Diversions</a>, Up: <a href="GNU-troff-Reference.html">GNU <code class="code">troff</code> Reference</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> |