Tasks

Julia has a built-in system for running tasks, which are, in general, known as coroutines. With this, a computation that generates values into a Channel (with a put! function) can be suspended as a task, while a consumer task can pick up the values (with a take! function). This is similar to the yield keyword in Python.

As a concrete example, let's take a look at a fib_producer function that calculates the first 10 Fibonacci numbers (refer to the Recursive functions section in Chapter 3, Functions), but it doesn't return the numbers, it produces them:

# code in Chapter 4\tasks.jl  
 function fib_producer(c::Channel) 
        a, b = (0, 1) 
        for i = 1:10 
            put!(c, b) 
            a, b = (b, a + b) 
        end 
    end 

Construct a Channel by providing this function as an argument:

chnl = Channel(fib_producer)

The task's state is now runnable...