Functions

#Functions A function can be defined in one of two ways.

fun add(a,b)
{
    return a+b;
}

or

add = fun(a,b)
{
    return a+b;
}

If a function completes execution without returning, it implicitly returns a null value.

#Generators Generators are functions that pause and return a value whenever a yield statement is hit.

A generator is returned by any function that uses the yield keyword.

fun generator_func()
{
    for (local i = 0; i < 10; i++)
        yield i;
}
generator = generator_func();

This generator would return 0 the first time it is called, then 1 the next time, then 2, so on and so forth until it hits 9. When the generator is run after it hits nine, it hits an implicit "return null;" statement and returns null. Then, the generator is finished and will throw an error if it is called again.

In order to check when a generator has returned, you can check the result of the ":done()" function on it as shown below.

local finished = generator:done();

It is also possible to use generators in a for each loop.

for (local x in generator)
{
    print(x);
}