141 lines
7.5 KiB
HTML
141 lines
7.5 KiB
HTML
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<!DOCTYPE html>
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<html>
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<!-- Created by GNU Texinfo 7.1, https://www.gnu.org/software/texinfo/ -->
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<!-- This manual documents Guile version 3.0.10.
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Copyright (C) 1996-1997, 2000-2005, 2009-2023 Free Software Foundation,
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Inc.
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Copyright (C) 2021 Maxime Devos
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Copyright (C) 2024 Tomas Volf
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU Free Documentation License, Version 1.3 or
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any later version published by the Free Software Foundation; with no
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Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A
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copy of the license is included in the section entitled "GNU Free
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Documentation License." -->
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<title>Scheme Write (Guile Reference Manual)</title>
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<meta name="description" content="Scheme Write (Guile Reference Manual)">
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<meta name="keywords" content="Scheme Write (Guile Reference Manual)">
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<meta name="resource-type" content="document">
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<meta name="distribution" content="global">
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<meta name="Generator" content=".texi2any-real">
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<meta name="viewport" content="width=device-width,initial-scale=1">
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<link href="index.html" rel="start" title="Top">
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<link href="Concept-Index.html" rel="index" title="Concept Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="Read_002fLoad_002fEval_002fCompile.html" rel="up" title="Read/Load/Eval/Compile">
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<link href="Fly-Evaluation.html" rel="next" title="Fly Evaluation">
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<link href="Annotated-Scheme-Read.html" rel="prev" title="Annotated Scheme Read">
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<style type="text/css">
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a.copiable-link {visibility: hidden; text-decoration: none; line-height: 0em}
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strong.def-name {font-family: monospace; font-weight: bold; font-size: larger}
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</style>
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<link rel="stylesheet" type="text/css" href="https://www.gnu.org/software/gnulib/manual.css">
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</head>
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<body lang="en">
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<div class="subsection-level-extent" id="Scheme-Write">
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<div class="nav-panel">
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<p>
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Next: <a href="Fly-Evaluation.html" accesskey="n" rel="next">Procedures for On the Fly Evaluation</a>, Previous: <a href="Annotated-Scheme-Read.html" accesskey="p" rel="prev">Reading Scheme Code, For the Compiler</a>, Up: <a href="Read_002fLoad_002fEval_002fCompile.html" accesskey="u" rel="up">Reading and Evaluating Scheme Code</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<h4 class="subsection" id="Writing-Scheme-Values"><span>6.16.4 Writing Scheme Values<a class="copiable-link" href="#Writing-Scheme-Values"> ¶</a></span></h4>
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<p>Any scheme value may be written to a port. Not all values may be read
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back in (see <a class="pxref" href="Scheme-Read.html">Reading Scheme Code</a>), however.
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</p>
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<a class="index-entry-id" id="index-write-4"></a>
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<a class="index-entry-id" id="index-print"></a>
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<dl class="first-deffn">
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<dt class="deffn" id="index-write"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">write</strong> <var class="def-var-arguments">obj [port]</var><a class="copiable-link" href="#index-write"> ¶</a></span></dt>
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<dd><p>Send a representation of <var class="var">obj</var> to <var class="var">port</var> or to the current
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output port if not given.
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</p>
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<p>The output is designed to be machine readable, and can be read back
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with <code class="code">read</code> (see <a class="pxref" href="Scheme-Read.html">Reading Scheme Code</a>). Strings are printed in
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double quotes, with escapes if necessary, and characters are printed in
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‘<samp class="samp">#\</samp>’ notation.
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</p></dd></dl>
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<a class="index-entry-id" id="index-display-4"></a>
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<dl class="first-deffn">
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<dt class="deffn" id="index-display"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">display</strong> <var class="def-var-arguments">obj [port]</var><a class="copiable-link" href="#index-display"> ¶</a></span></dt>
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<dd><p>Send a representation of <var class="var">obj</var> to <var class="var">port</var> or to the current
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output port if not given.
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</p>
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<p>The output is designed for human readability, it differs from
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<code class="code">write</code> in that strings are printed without double quotes and
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escapes, and characters are printed as per <code class="code">write-char</code>, not in
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‘<samp class="samp">#\</samp>’ form.
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</p></dd></dl>
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<p>As was the case with the Scheme reader, there are a few options that
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affect the behavior of the Scheme printer.
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</p>
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<a class="index-entry-id" id="index-options-_002d-print"></a>
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<a class="index-entry-id" id="index-print-options"></a>
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<dl class="first-deffn">
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<dt class="deffn" id="index-print_002doptions"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">print-options</strong> <var class="def-var-arguments">[setting]</var><a class="copiable-link" href="#index-print_002doptions"> ¶</a></span></dt>
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<dd><p>Display the current settings of the read options. If <var class="var">setting</var> is
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omitted, only a short form of the current read options is
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printed. Otherwise if <var class="var">setting</var> is the symbol <code class="code">help</code>, a
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complete options description is displayed.
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</p></dd></dl>
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<p>The set of available options, and their default values, may be had by
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invoking <code class="code">print-options</code> at the prompt.
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</p>
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<div class="example smalllisp lisp">
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<pre class="lisp-preformatted">scheme@(guile-user)> (print-options)
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(quote-keywordish-symbols reader highlight-suffix "}" highlight-prefix "{")
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scheme@(guile-user)> (print-options 'help)
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highlight-prefix { The string to print before highlighted values.
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highlight-suffix } The string to print after highlighted values.
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quote-keywordish-symbols reader How to print symbols that have a colon
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as their first or last character. The
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value '#f' does not quote the colons;
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'#t' quotes them; 'reader' quotes them
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when the reader option 'keywords' is
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not '#f'.
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escape-newlines yes Render newlines as \n when printing
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using `write'.
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r7rs-symbols no Escape symbols using R7RS |...| symbol
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notation.
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</pre></div>
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<p>These options may be modified with the print-set! syntax.
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</p>
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<dl class="first-deffn">
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<dt class="deffn" id="index-print_002dset_0021"><span class="category-def">Scheme Syntax: </span><span><strong class="def-name">print-set!</strong> <var class="def-var-arguments">option-name value</var><a class="copiable-link" href="#index-print_002dset_0021"> ¶</a></span></dt>
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<dd><p>Modify the print options. Due to historical oddities, <code class="code">print-set!</code>
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is a macro that expects an unquoted option name.
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</p></dd></dl>
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</div>
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<hr>
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<div class="nav-panel">
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<p>
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Next: <a href="Fly-Evaluation.html">Procedures for On the Fly Evaluation</a>, Previous: <a href="Annotated-Scheme-Read.html">Reading Scheme Code, For the Compiler</a>, Up: <a href="Read_002fLoad_002fEval_002fCompile.html">Reading and Evaluating Scheme Code</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html" title="Index" rel="index">Index</a>]</p>
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</div>
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</body>
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</html>
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