Forall

Definitions

1. A universal quantifier in type theory and languages like Haskell that introduces type variables scoped over a type signature, enabling parametric polymorphism. 'forall a. a -> a' means 'for any type a, a function from a to a.'

   In plain English: A keyword meaning 'this works for every possible type' — it's how languages like Haskell express generic, reusable code at the type level.

   Example: "The forall in the type signature tells the compiler this function works for literally any type."

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