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# Haskell

## Basic idea

Pure, lazy, statically typed functional language (1990). Every expression is referentially transparent; effects are confined to the type system via monads. The premier industrial vehicle for type-system research.

## Key facts

* Year: 1990; committee design from FPCA community.
* Paradigm: pure functional, lazy.
* Typing: static, strong, Hindley-Milner + type classes (System Fω under GHC).
* Memory: garbage-collected; closures and thunks heap-allocated.
* Effects: `IO`, `ST`, monad transformers.