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<html>
<head>
<title>Teachpack : Directories</title>
</head>
<body bgcolor="#ffffff" text="#000000"
link="#009900" vlink="#007700" alink="#cc0000">
<a href="index.html">Teachpacks for How to Design Programs</a>
<h1>Directories</h1>
<hr> <h3><a name="dir.ss">dir.ss</a></h3> <!-- DOCNOTE="teach=dir.ss" -->
<p>The teachpack <code>dir.ss</code> provides two-structures and one
operation:
<menu>
<li> <code>(define-struct dir (names dirs files))</code>
<li> <code>(define-struct file (name size content))</code>
<li> <code><a name="create-dir">create-dir</a></code> which consumes a directory path (a string)
and produces a directory.
</menu>
<p>The teachpack relies on two data definitions:
<menu>
<li>
A directory is
<code>(<a name="make-dir">make-dir</a> string[path] (listof directory) (listof file))</code>
<li>
A file is <code>(<a name="make-file">make-file</a> string[file name])</code>
</menu>
Sample: Set teachpack to <code>dir.ss</code> and execute. Then evaluate
<pre>
> (create-dir ".")
(make-dir
'|.|
empty
(cons (make-file 'ball1.gif 1289 empty)
(cons (make-file 'blueball.gif 205 empty)
(cons (make-file 'greenbal.gif 204 empty)
(cons (make-file 'redball.gif 203 empty)
(cons (make-file 'ufo.gif 1044 empty)
(cons (make-file 'gif-test.ss 5811 empty)
empty)))))))
</pre>
<p>Note: Softlinks are always treated as if they were empty files.
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<br>
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