Functions#

Macros can become very long... And we all have a tendency of reusing code by pasting it across the script.

One way to avoid code duplication is to place them into a function. A function is a block of code that can be called from anywhere in the script.

For instance in this snippet, there are some duplications:

array1 = newArray(5);

for (i = 0; i < array1.length; i++) {
 array1[i] = (i * array1.length / 90) * (PI / 180);
}
Array.print(array1);


array2 = newArray(10);
for (i = 0; i < array2.length; i++) {
 array2[i] = (i * array2.length / 90) * (PI / 180);
}
Array.print(array2);

Pretty cumbersome, isn't it?

A function can be used to avoid this duplication:

function fillArray(size) { // (1)!
    // (2)!
    array = newArray(size);

    for (i = 0; i < size; i++) {
        array[i] = (i * size / 90) * (PI / 180);
    }

    Array.print(array);

    return array; // (3)!
}

array1 = fillArray(5); // (4)!
array2 = fillArray(10);

1. Function declaration
2. Function body
3. Return statement
4. Function call

Pretty neat!

Function declaration#

A function is declared using the function keyword followed by the function name and a list of parameters between parentheses. The function body is enclosed between curly brackets.

function functionName(parameter1, parameter2, ...) {
    // Function body
    return returnValue; // (1)!
}

1. The return is optional!

When to use functions?#

Whenever you are going to use the same lines of code more than once, you should consider using a function.

You can declare multiple functions in the same script. What is important is to keep the code clean. Smaller functions are easier to test and to debug, as you can call them with different parameter values and check the output.