132 lines
7.1 KiB
HTML
132 lines
7.1 KiB
HTML
|
<!DOCTYPE html>
|
||
|
|
<html>
|
||
|
|
<!-- Created by GNU Texinfo 7.1, https://www.gnu.org/software/texinfo/ -->
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
||
|
|
<!-- This manual documents Guile version 3.0.10.
|
||
|
|
|
||
|
|
Copyright (C) 1996-1997, 2000-2005, 2009-2023 Free Software Foundation,
|
||
|
|
Inc.
|
||
|
|
|
||
|
|
Copyright (C) 2021 Maxime Devos
|
||
|
|
|
||
|
|
Copyright (C) 2024 Tomas Volf
|
||
|
|
|
||
|
|
|
||
|
|
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>Sloppy Alist Functions (Guile Reference Manual)</title>
|
||
|
|
|
||
|
|
<meta name="description" content="Sloppy Alist Functions (Guile Reference Manual)">
|
||
|
|
<meta name="keywords" content="Sloppy Alist Functions (Guile Reference Manual)">
|
||
|
|
<meta name="resource-type" content="document">
|
||
|
|
<meta name="distribution" content="global">
|
||
|
|
<meta name="Generator" content=".texi2any-real">
|
||
|
|
<meta name="viewport" content="width=device-width,initial-scale=1">
|
||
|
|
|
||
|
|
<link href="index.html" rel="start" title="Top">
|
||
|
|
<link href="Concept-Index.html" rel="index" title="Concept Index">
|
||
|
|
<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
|
||
|
|
<link href="Association-Lists.html" rel="up" title="Association Lists">
|
||
|
|
<link href="Alist-Example.html" rel="next" title="Alist Example">
|
||
|
|
<link href="Removing-Alist-Entries.html" rel="prev" title="Removing Alist Entries">
|
||
|
|
<style type="text/css">
|
||
|
|
<!--
|
||
|
|
a.copiable-link {visibility: hidden; text-decoration: none; line-height: 0em}
|
||
|
|
div.example {margin-left: 3.2em}
|
||
|
|
span:hover a.copiable-link {visibility: visible}
|
||
|
|
strong.def-name {font-family: monospace; font-weight: bold; font-size: larger}
|
||
|
|
-->
|
||
|
|
</style>
|
||
|
|
<link rel="stylesheet" type="text/css" href="https://www.gnu.org/software/gnulib/manual.css">
|
||
|
|
|
||
|
|
|
||
|
|
</head>
|
||
|
|
|
||
|
|
<body lang="en">
|
||
|
|
<div class="subsubsection-level-extent" id="Sloppy-Alist-Functions">
|
||
|
|
<div class="nav-panel">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Alist-Example.html" accesskey="n" rel="next">Alist Example</a>, Previous: <a href="Removing-Alist-Entries.html" accesskey="p" rel="prev">Removing Alist Entries</a>, Up: <a href="Association-Lists.html" accesskey="u" rel="up">Association Lists</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>
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<h4 class="subsubsection" id="Sloppy-Alist-Functions-1"><span>6.6.20.5 Sloppy Alist Functions<a class="copiable-link" href="#Sloppy-Alist-Functions-1"> ¶</a></span></h4>
|
||
|
|
|
||
|
|
<p><code class="code">sloppy-assq</code>, <code class="code">sloppy-assv</code> and <code class="code">sloppy-assoc</code> behave
|
||
|
|
like the corresponding non-<code class="code">sloppy-</code> procedures, except that they
|
||
|
|
return <code class="code">#f</code> when the specified association list is not well-formed,
|
||
|
|
where the non-<code class="code">sloppy-</code> versions would signal an error.
|
||
|
|
</p>
|
||
|
|
<p>Specifically, there are two conditions for which the non-<code class="code">sloppy-</code>
|
||
|
|
procedures signal an error, which the <code class="code">sloppy-</code> procedures handle
|
||
|
|
instead by returning <code class="code">#f</code>. Firstly, if the specified alist as a
|
||
|
|
whole is not a proper list:
|
||
|
|
</p>
|
||
|
|
<div class="example">
|
||
|
|
<pre class="example-preformatted">(assoc "mary" '((1 . 2) ("key" . "door") . "open sesame"))
|
||
|
|
⇒
|
||
|
|
ERROR: In procedure assoc in expression (assoc "mary" (quote #)):
|
||
|
|
ERROR: Wrong type argument in position 2 (expecting
|
||
|
|
association list): ((1 . 2) ("key" . "door") . "open sesame")
|
||
|
|
|
||
|
|
(sloppy-assoc "mary" '((1 . 2) ("key" . "door") . "open sesame"))
|
||
|
|
⇒
|
||
|
|
#f
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>Secondly, if one of the entries in the specified alist is not a pair:
|
||
|
|
</p>
|
||
|
|
<div class="example">
|
||
|
|
<pre class="example-preformatted">(assoc 2 '((1 . 1) 2 (3 . 9)))
|
||
|
|
⇒
|
||
|
|
ERROR: In procedure assoc in expression (assoc 2 (quote #)):
|
||
|
|
ERROR: Wrong type argument in position 2 (expecting
|
||
|
|
association list): ((1 . 1) 2 (3 . 9))
|
||
|
|
|
||
|
|
(sloppy-assoc 2 '((1 . 1) 2 (3 . 9)))
|
||
|
|
⇒
|
||
|
|
#f
|
||
|
|
</pre></div>
|
||
|
|
|
||
|
|
<p>Unless you are explicitly working with badly formed association lists,
|
||
|
|
it is much safer to use the non-<code class="code">sloppy-</code> procedures, because they
|
||
|
|
help to highlight coding and data errors that the <code class="code">sloppy-</code>
|
||
|
|
versions would silently cover up.
|
||
|
|
</p>
|
||
|
|
<dl class="first-deffn">
|
||
|
|
<dt class="deffn" id="index-sloppy_002dassq"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">sloppy-assq</strong> <var class="def-var-arguments">key alist</var><a class="copiable-link" href="#index-sloppy_002dassq"> ¶</a></span></dt>
|
||
|
|
<dt class="deffnx def-cmd-deffn" id="index-scm_005fsloppy_005fassq"><span class="category-def">C Function: </span><span><strong class="def-name">scm_sloppy_assq</strong> <var class="def-var-arguments">(key, alist)</var><a class="copiable-link" href="#index-scm_005fsloppy_005fassq"> ¶</a></span></dt>
|
||
|
|
<dd><p>Behaves like <code class="code">assq</code> but does not do any error checking.
|
||
|
|
Recommended only for use in Guile internals.
|
||
|
|
</p></dd></dl>
|
||
|
|
|
||
|
|
<dl class="first-deffn">
|
||
|
|
<dt class="deffn" id="index-sloppy_002dassv"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">sloppy-assv</strong> <var class="def-var-arguments">key alist</var><a class="copiable-link" href="#index-sloppy_002dassv"> ¶</a></span></dt>
|
||
|
|
<dt class="deffnx def-cmd-deffn" id="index-scm_005fsloppy_005fassv"><span class="category-def">C Function: </span><span><strong class="def-name">scm_sloppy_assv</strong> <var class="def-var-arguments">(key, alist)</var><a class="copiable-link" href="#index-scm_005fsloppy_005fassv"> ¶</a></span></dt>
|
||
|
|
<dd><p>Behaves like <code class="code">assv</code> but does not do any error checking.
|
||
|
|
Recommended only for use in Guile internals.
|
||
|
|
</p></dd></dl>
|
||
|
|
|
||
|
|
<dl class="first-deffn">
|
||
|
|
<dt class="deffn" id="index-sloppy_002dassoc"><span class="category-def">Scheme Procedure: </span><span><strong class="def-name">sloppy-assoc</strong> <var class="def-var-arguments">key alist</var><a class="copiable-link" href="#index-sloppy_002dassoc"> ¶</a></span></dt>
|
||
|
|
<dt class="deffnx def-cmd-deffn" id="index-scm_005fsloppy_005fassoc"><span class="category-def">C Function: </span><span><strong class="def-name">scm_sloppy_assoc</strong> <var class="def-var-arguments">(key, alist)</var><a class="copiable-link" href="#index-scm_005fsloppy_005fassoc"> ¶</a></span></dt>
|
||
|
|
<dd><p>Behaves like <code class="code">assoc</code> but does not do any error checking.
|
||
|
|
Recommended only for use in Guile internals.
|
||
|
|
</p></dd></dl>
|
||
|
|
|
||
|
|
</div>
|
||
|
|
<hr>
|
||
|
|
<div class="nav-panel">
|
||
|
|
<p>
|
||
|
|
Next: <a href="Alist-Example.html">Alist Example</a>, Previous: <a href="Removing-Alist-Entries.html">Removing Alist Entries</a>, Up: <a href="Association-Lists.html">Association Lists</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>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|