98 lines
4.1 KiB
HTML
98 lines
4.1 KiB
HTML
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<html lang="en">
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<head>
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<title>Functions - Enigma</title>
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<meta name="description" content="Enigma">
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<meta name="generator" content="makeinfo 4.13">
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<link title="Top" rel="start" href="index.html#Top">
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<link rel="up" href="Language.html#Language" title="Language">
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<link rel="prev" href="Files.html#Files" title="Files">
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<link rel="next" href="Conditionals.html#Conditionals" title="Conditionals">
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<link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage">
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<!--
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This manual is for Enigma, version 0.1.
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Copyright (C) 2010 Niels Serup
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Permission is granted to copy, distribute and/or modify this
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document under the terms of the GNU Free Documentation License,
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Version 1.3 or any later version published by the Free Software
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Foundation; with no Invariant Sections, no Front-Cover Texts, and
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no Back-Cover Texts. A copy of the license is included in the
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section entitled "GNU Free Documentation License".
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This document is also available under the terms of the Creative
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Commons Attribution-Share Alike 3.0 (or any later version)
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Unported license. A copy of the license is available at
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`http://creativecommons.org/licenses/by-sa/3.0/legalcode'.
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</head>
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<body>
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<div class="node">
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<a name="Functions"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="Conditionals.html#Conditionals">Conditionals</a>,
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Previous: <a rel="previous" accesskey="p" href="Files.html#Files">Files</a>,
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Up: <a rel="up" accesskey="u" href="Language.html#Language">Language</a>
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<hr>
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</div>
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<h3 class="section">2.7 Functions</h3>
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<p><a name="index-functions-14"></a>Functions are defined and called using the following syntax:
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<pre class="verbatim"># Defining them
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{stdout "Hello" ! write;} = func;
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{/x,y/stdout "x=" x ", y=" y!write;} = coorprint;
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{stdout args ! write;} = aprint;
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# Calling them
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!func; # Outputs "Hello"
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52 12 ! coorprint; # Outputs "x=52, y=12"
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999 "abc" 21 ! aprint; # Outputs "999 abc 21"
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</pre>
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<p>Arguments can thus be accessed either by using the <code>/.../</code> syntax
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in the beginning of the function or by using the local <code>args</code>
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variable. Furthermore, to make <em>all</em> new variables save in the
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global space, prepend the function content with a <code>*</code>. This will
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have the same effect as replacing all <code>=</code> signs in the function
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with the <code>*</code> operator.
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<p>Remember that your file is also a function, just without the curly
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brackets. This means that when working on the top level of your program,
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<code>args</code> actually refer to the arguments specified on the command
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line. All arguments are strings, but built-in functions that can convert
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them to numbers exist.
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<p>The previous example functions did not have any return values. This is
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merely because they didn't need such things. To define a return value,
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the return value must be sent to the special variable <code>return</code>.
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<pre class="verbatim">{/a,b/a b ! multiply = return;} = 2mul;
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33 3 ! 2mul = 2mult;
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stdout 2mult ! write;
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</pre>
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The execution of a function does <em>not</em> stop when a value
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is assigned to <code>return</code>. This has both advantages and
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disadvantages.
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<p>Many things are almost impossible to do without the built-in
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functions. Some are completely impossible. See <a href="Built_002dIn.html#Built_002dIn">Built-In</a>. As all
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objects in Enigma are pointers, several built-in functions actually
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modify the objects sent to them as arguments. To solve this problem, one
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must use the <code>clone</code> function.
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</body></html>
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