100 lines
3.8 KiB
HTML
100 lines
3.8 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>Alist Example (Guile Reference Manual)</title>
|
|
|
|
<meta name="description" content="Alist Example (Guile Reference Manual)">
|
|
<meta name="keywords" content="Alist Example (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="Sloppy-Alist-Functions.html" rel="prev" title="Sloppy Alist Functions">
|
|
<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}
|
|
-->
|
|
</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="Alist-Example">
|
|
<div class="nav-panel">
|
|
<p>
|
|
Previous: <a href="Sloppy-Alist-Functions.html" accesskey="p" rel="prev">Sloppy Alist Functions</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="Alist-Example-1"><span>6.6.20.6 Alist Example<a class="copiable-link" href="#Alist-Example-1"> ¶</a></span></h4>
|
|
|
|
<p>Here is a longer example of how alists may be used in practice.
|
|
</p>
|
|
<div class="example lisp">
|
|
<pre class="lisp-preformatted">(define capitals '(("New York" . "Albany")
|
|
("Oregon" . "Salem")
|
|
("Florida" . "Miami")))
|
|
|
|
;; What's the capital of Oregon?
|
|
(assoc "Oregon" capitals) ⇒ ("Oregon" . "Salem")
|
|
(assoc-ref capitals "Oregon") ⇒ "Salem"
|
|
|
|
;; We left out South Dakota.
|
|
(set! capitals
|
|
(assoc-set! capitals "South Dakota" "Pierre"))
|
|
capitals
|
|
⇒ (("South Dakota" . "Pierre")
|
|
("New York" . "Albany")
|
|
("Oregon" . "Salem")
|
|
("Florida" . "Miami"))
|
|
|
|
;; And we got Florida wrong.
|
|
(set! capitals
|
|
(assoc-set! capitals "Florida" "Tallahassee"))
|
|
capitals
|
|
⇒ (("South Dakota" . "Pierre")
|
|
("New York" . "Albany")
|
|
("Oregon" . "Salem")
|
|
("Florida" . "Tallahassee"))
|
|
|
|
;; After Oregon secedes, we can remove it.
|
|
(set! capitals
|
|
(assoc-remove! capitals "Oregon"))
|
|
capitals
|
|
⇒ (("South Dakota" . "Pierre")
|
|
("New York" . "Albany")
|
|
("Florida" . "Tallahassee"))
|
|
</pre></div>
|
|
|
|
</div>
|
|
|
|
|
|
|
|
</body>
|
|
</html>
|