## Functions (subs)

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:

    sub nameGoesHere (parameter1, parameter2, andSoOn) {
       # Some code
    }

It is also possible to return values from a function. Functions can return any of the data types which can be stored in a variable (you can therefore use a stack if you need to return more than one value from a function).

    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 + "!");
    }

When calling a function, simply type the name of the function followed by the parameters in brackets. For example:

    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);
    }

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!

    sub reallyImportantFunction () {
       say (ego, "It's vital that I say this!");
    }

    sub init () {

       # This won't call the reallyImportantFunction...
       reallyImportantFunction;

       # But this will...
       reallyImportantFunction ();
    }

### More on this subject:

Passing Functions as Variables

Unfreezable Functions

spawnSub()

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