monadsMonads for Crystal

Composable Maybe, Either, List, Try and Task — chain instructions, tame nil, and handle errors without exceptions.

Avoid nil

The Maybe monad replaces nil checks with Just and Nothing, so absent values can never slip through unhandled.

The Either monad carries a success or an error value through a chain, deferring failure handling to the end.

Try and Task wrap exception-throwing code into monads, with Task running the work on a fiber.

fmap, bind, and fold work the same way across every monad, plus the | and >> operators for chaining.