Using Functions

The former example raises a question, will we always need to type

some_freq  => sine.freq;
some_duration => now;

everytime we want to set the frequency and advance time?

Functions as mean to encapsulate behavior

Well, no: this can all fit in a function. Let's write it

fun void play(SinOsc sine, const float freq, const dur d) {
  freq => sine.freq;
  d => now;
}

What does this mean?

the fun keyword denotes the start of a function declaration.

the return type of the function follows.
here the function returns nothing, we declare it as void.

After that there is the function name, play in this case.

What follows is the argument list.
A function argument syntax is as follow:

Type name

A simple example function

Let's write a simple adder

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

This time the function returns an int, so we change the return type accordingly.

Here is how we call it

fun int add(int a, int b) {
  return a + b;
}
<<< add(1, 2) >>>;

#! alternatively
<<< (2, 3) => add >>>;

A example using functions

#import Modules

fun void play(SinOsc sine, const float freq, const dur d) {
  freq => sine.freq;
  d => now;
}

var SinOsc sine ~> dac;

play(sine, 440, second);
play(sine, 220, .5::second);
play(sine, 220, .5::second);
play(sine, 440, second);