base

Core data structures and operations.

Haskell's base library provides, among other things, core types (e.g. Bool and Int), data structures (e.g. List, Tuple and Maybe), the Exception mechanism, and the IO & Concurrency operations. The Prelude module, which is imported by default, exposes a curated set of types and functions from other modules.

Other data structures like Map, Set are available in the containers library. To work with textual data, use the text library.