Philosophy and "for" loops — more from Go and Rust

My experience with Haskell has been that the syntax, execution model, and standard libraries aren't particularly difficult to pick up, but learning to write idiomatic Haskell code (i.e. not all in the IO and/or State monads) to solve common problems can take a long time, particularly when your reference material is assuming a procedural language with mutable variables. Some of the algorithms and data structures frequently used in procedural programs do not translate well to languages where data is immutable by default. The trade-off, of course, is that immutable data eliminates many of the more common kinds of programming errors.

Debugging can also be an issue, a common problem for non-strict languages, though Haskell does have some useful tools in that area--and is known for having less need for debugging to begin with thanks to its expressive type system.