Scala Monads — Option, Either, Future as Contextual Computations

Why it matters

Monads are Scala's compositional workhorse. Understanding shapes idiomatic code.

The architecture

Monad: type with unit (pure) and flatMap (bind).

for-comprehension: syntactic sugar for flatMap chains.

How it works end to end

Option.flatMap: chain nullable computations without null checks.

Either.flatMap: chain error-carrying computations.

Future.flatMap: chain async without callbacks.

for-comprehension: 'for { x <- a; y <- b } yield x + y' desugars to flatMap chain.