Functional programming encourages us to program without mutable state. Instead we compose functions that can be viewed as state transformers. It’s a change of perspective that can have a big impact on how we reason about our code. But it’s also a change of perspective that can be useful in mathematics and I’d like to give an example: a really beautiful technique that alows you to sample from the infinite limit of a probability distribution without needing an infinite number of operations.

source: trivium