Course of Raku / Functional, concurrent, reactive, and web programming / Reactive programming

react and whenever

Tapping a single supply is fine, but real reactive programs often watch several streams at once and react to whichever produces a value next. Raku has dedicated syntax for this: the react block, with one or more whenever blocks inside it.

A react block sets up the reactions and then waits, running each whenever body as its supply emits — until all the supplies are done. This section shows how the two work together.

Topics in this section

Practice

Complete the quizzes that cover the contents of this section.

Exercises

This section contains 3 exercises. Examine all the topics of this section before doing the coding practice.

  1. Collect with react
  2. Collect with react
  3. Two whenevers

Course navigation

Solution: Sum a live feed   |   The react block