My main problem with functional programming (mostly based on some experience with Haskell) is that I find it really hard to estimate the performance (in terms o

My main problem with functional programming (mostly based on some experience with Haskell) is that I find it really hard to estimate the performance (in terms of runtime and memory consumption) of programs. It's really nice to structure your program around types and build your program via function composition - but getting it performant (let's say similar to C, Rust or Java) is far from simple. In particular performant Haskell does not look like idiomatic Haskell, whereas performant C, Rust or Java does. Now don't get me wrong - I absolutely love the idea of functional programming and λ-calculus is a beautiful system to express computation, but in practice it's still hard to make performant while keeping a readable style. Maybe Idris 2 can close the gap?