Learn Functional Programming with Elixir

Tail-Call Optimization

Every time we call a function, it consumes memory. Usually we don’t need to worry much about it—machines today have plenty of memory, and the Erlang VM does a great job keeping computation costs low for a decent amount of data. But when some input makes our function do millions of recursive calls, that consumes significant memory. In this section, we’ll discuss a way of creating recursive functions that have constant and low memory consumption. We’ll take advantage of compiler tail-call optimization.

Tail-call optimization is when the compiler reduces functions in memory without allocating more memory. It’s a common compiler feature in functional programming languages. To use it, we need to ensure that the last expression ...