.hs File — Haskell Source Code

Haskell is a purely functional programming language with strong static typing, lazy evaluation, and type inference, named after logician Haskell Curry. HS files contain source code in a language that has profoundly influenced programming language design since its inception in 1990. Haskell's type system includes algebraic data types, type classes (a form of ad-hoc polymorphism that inspired Rust traits and Scala implicits), higher-kinded types, monads for managing side effects, and GADTs (Generalized Algebraic Data Types). Lazy evaluation means expressions are only computed when their values are needed, enabling elegant definitions of infinite data structures and efficient computation. The GHC (Glasgow Haskell Compiler) is a highly optimizing compiler that produces efficient native code. Haskell is used in financial technology (Standard Chartered, Bloomberg), blockchain (Cardano), security-critical systems, compilers, and academia. Libraries like Pandoc (universal document converter), xmonad (window manager), and Servant (type-safe web APIs) demonstrate Haskell's practical applications. The language's strong guarantees about purity and type safety make it particularly suitable for applications where correctness is critical.