90 lines
4.3 KiB
HTML
90 lines
4.3 KiB
HTML
<!DOCTYPE html>
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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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Documentation License." -->
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<title>and or (Guile Reference Manual)</title>
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<meta name="description" content="and or (Guile Reference Manual)">
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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="Control-Mechanisms.html" rel="up" title="Control Mechanisms">
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<link href="while-do.html" rel="next" title="while do">
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<link href="Conditionals.html" rel="prev" title="Conditionals">
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<div class="subsection-level-extent" id="and-or">
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<div class="nav-panel">
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<p>
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Next: <a href="while-do.html" accesskey="n" rel="next">Iteration mechanisms</a>, Previous: <a href="Conditionals.html" accesskey="p" rel="prev">Simple Conditional Evaluation</a>, Up: <a href="Control-Mechanisms.html" accesskey="u" rel="up">Controlling the Flow of Program Execution</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="Conditional-Evaluation-of-a-Sequence-of-Expressions"><span>6.11.3 Conditional Evaluation of a Sequence of Expressions<a class="copiable-link" href="#Conditional-Evaluation-of-a-Sequence-of-Expressions"> ¶</a></span></h4>
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<p><code class="code">and</code> and <code class="code">or</code> evaluate all their arguments in order, similar
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to <code class="code">begin</code>, but evaluation stops as soon as one of the expressions
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evaluates to false or true, respectively.
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</p>
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<dl class="first-deffn">
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<dt class="deffn" id="index-and"><span class="category-def">syntax: </span><span><strong class="def-name">and</strong> <var class="def-var-arguments">expr …</var><a class="copiable-link" href="#index-and"> ¶</a></span></dt>
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<dd><p>Evaluate the <var class="var">expr</var>s from left to right and stop evaluation as soon
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as one expression evaluates to <code class="code">#f</code>; the remaining expressions are
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not evaluated. The value of the last evaluated expression is returned.
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If no expression evaluates to <code class="code">#f</code>, the value of the last
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expression is returned.
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</p>
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<p>If used without expressions, <code class="code">#t</code> is returned.
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</p></dd></dl>
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<dl class="first-deffn">
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<dt class="deffn" id="index-or"><span class="category-def">syntax: </span><span><strong class="def-name">or</strong> <var class="def-var-arguments">expr …</var><a class="copiable-link" href="#index-or"> ¶</a></span></dt>
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<dd><p>Evaluate the <var class="var">expr</var>s from left to right and stop evaluation as soon
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as one expression evaluates to a true value (that is, a value different
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from <code class="code">#f</code>); the remaining expressions are not evaluated. The value
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of the last evaluated expression is returned. If all expressions
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evaluate to <code class="code">#f</code>, <code class="code">#f</code> is returned.
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</p>
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<p>If used without expressions, <code class="code">#f</code> is returned.
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</p></dd></dl>
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</div>
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</body>
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</html>
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