Haskell is a statically-typed, purely functional programming language that was first developed in 1990. It draws its roots from mathematical concepts and provides a strong type system that ensures [[safety]] and [[correctness]] of programs. Haskell is named after [[Haskell Curry]], a logician who made significant contributions to the field of mathematical logic. Some key features of Haskell include: 1. Purely Functional: Haskell promotes the paradigm of functional programming, where functions are treated as first-class citizens and immutable data structures are preferred. This allows for writing code that is concise, modular, and easy to reason about. 2. Lazy Evaluation: Haskell uses lazy evaluation by default, meaning that expressions are not evaluated until their values are actually needed. This enables the language to handle potentially infinite data structures and increases efficiency in certain cases. 3. Strong Type System: Haskell has a powerful type system that ensures strong static typing and type inference. It prevents many common programming errors by enforcing strict type checking and offers features like parametric polymorphism and type classes for generic programming. 4. Pattern Matching: Pattern matching is a fundamental feature in Haskell that allows developers to match values against patterns and execute corresponding code blocks. It simplifies handling different cases explicitly and makes code more readable. 5. Higher-Order Functions: In Haskell, functions can be passed as arguments to other functions or returned as results from functions—this is known as higher-order functions. It enables developers to write more reusable and modular code. 6. Concurrency Support: Haskell provides built-in support for concurrent programming through lightweight threads known as "Haskell threads" or "green threads." These threads can be managed efficiently by the runtime system without requiring operating system-level threads. 7. Rich Ecosystem: Haskell has a thriving open-source community with numerous libraries and frameworks available for various purposes such as web development (Yesod, Snap), parsing (Parsec), testing (QuickCheck), and many others. Haskell's emphasis on purity, strong typing, and mathematical foundations make it a popular choice for areas like formal verification, compiler construction, and academic research. While it may have a steeper learning curve compared to some other languages, Haskell rewards developers with its elegance, expressiveness, and the ability to write robust and maintainable code.l