The task is to write a program that computes Fibonacci numbers such that it is obvious the program is correct. It's a sort of "Fibonacci readable" benchmark, and I contend to there exists no solution written in an imperative style that is satisfactory.
I figured I'd present some benchmarks I did because I think it gives some nice examples of the wrong tool for the job. Most of these are from answers on StackOverflow.
I wanted to share a little example I came across while working on one of my Idris libraries. It's matrix multiplication, but from an angle you may not be used to. In particular, though it is written in Idris (a strict language), it composes as well arrays in Haskell or another lazy language thanks to dependent types.
One way to define laziness is as follows: a language has strict evaluation if and only if \(f(\bot) = \bot\) for every function \(f\) definable in the language.
I've been using Idris for a while, and today I stumbled into an example of a dynamorphism that worked so beautifully I had to share. It is a stellar example not only of dependent types but also the rôle abstraction can play in writing correct code.next