Streams

A Stream is a series of elements that you can obtain one after another in a lazy fashion. It is very similar to an Array with the difference that it is lazy. Laziness means that instead of holding all values of the stream in memory (like an array does), values are generated on demand by a function. Therefore, a stream can, in principle, offer infinitely many values, which is impossible for an array! For example, we can define a function that gives us all integers.

~val = 0;
f = {~val = ~val + 1; ~val;};
f.();

If we evaluate the last line multiple times, we get 1, 2, 3, and so on. f represents an infinite stream of values. We can use FuncStream to create a Stream of integers, i.e., an object that understands certain messages. Then we can call next on the stream to get the next value. If a (finite) stream runs out of values, it returns nil.

(
~val = 0;
f = {~val = ~val + 1; ~val;};
x = FuncStream(f);
)
x.next(); // 1
x.next(); // 2
x.next(); // 3

In sclang everything is an Object and the class Object defines next to return the object itself. Therefore, every object is a Stream that streams itself. Consequently, almost everything can be viewed as a stream. A 5 is a stream returning 5. Calling next on an array will return itself.

5.next();  // 5
"hello".next; // "hello"
[1,2,3,4].next; // [1,2,3,4]
SinOsc().next // SinOsc

Everything is a Stream

In Supercollider’s sclang everything is a stream.