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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
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<TITLE>Functions (subs)</TITLE>
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<div align="center"><img id="headerGraphic" src="images/sludge300.png" alt="SLUDGE"/></div>
<h2>Functions (subs)</h2>
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<P>
In SLUDGE, a function or "sub" is a group of instructions which make up a particular task. Each function has a name, a set of parameters (values which can be passed in) and a list of commands. A function is defined in the following way:
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<P>
<pre>sub nameGoesHere (parameter1, parameter2, andSoOn) {
# Some code
}</pre>
</P>
<P>
It is also possible to return values from a function. Functions can return any of the data types which can be stored in a <a href="Variables.html">variable</a> (you can therefore use a <a href="The_Multi-Purpose_Stack___Array___Queue_Type.html">stack</a> if you need to return more than one value from a function).
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<P>
<pre>sub addTwoNumbers (a, b) {
return a + b;
}
sub introducePeople (aBod, anotherBod) {
# Let's return a stack containing "A, I'd like you to meet B."
# and "B, this is A!".
return newStack (aBod + ", I'd like you to meet " + anotherBod + ".",
anotherBod + ", this is " + aBod + "!");
}</pre>
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<P>
When calling a function, simply type the name of the function followed by the parameters in brackets. For example:
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<pre>sub sayNumber (number) {
say (ego, "The number is " + number + ".");
}
sub init () {
# Let's call our addTwoNumbers function
var total = addTwoNumbers (100, 451);
# Now let's call our new sayNumber function
sayNumber (total);
}</pre>
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<P>
If you are calling a function which needs no parameters, make sure you still include an empty set of brackets, otherwise the function will not be called!
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<pre>sub reallyImportantFunction () {
say (ego, "It's vital that I say this!");
}
sub init () {
# This won't call the reallyImportantFunction...
reallyImportantFunction;
# But this will...
reallyImportantFunction ();
}</pre>
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<H3>More on this subject:</H3>
<P>
<a href="Passing_Functions_as_Variables.html">Passing Functions as Variables</a>
</P>
<P>
<a href="Unfreezable_Functions.html">Unfreezable Functions</a>
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<P>
<a href="spawnSub.html">spawnSub()</a>
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<P class="copyright-notice">SLUDGE and this SLUDGE documentation are <A HREF="Copyright.html">copyright</A> Hungry Software and contributors 2000-2012
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