What is Haskell programming language?

Haskell is a statically typedA statically-typed language is the one which checks variable and expression types at compile-time before execution., purely functional programming language that was developed by a group of researchers and academics known as the Haskell Committee. The first version of Haskell, known as Haskell 1.0, appeared in the year 1990, and the language has since been used in academia and research, industry, and open-source development.

Basic program

Here's a simple program in Haskell that prints "Welcome to Educative" on the console.

main :: IO ()
main = putStrLn "Welcome to Educative"

  • Line 1: We declare the function main, which has the type IO(), meaning that the function performs some input/output operations.

  • Line 2: We print the phrase "Welcome to Educative" on the console using Haskell's putStrLn function.

Nature of the language

Haskell is a non-strict, purely functional programming language in nature. Let's quickly discuss what these terms mean:

  • Non-strict language: A non-strict language is one that follows lazy evaluation or call-by-need mechanism, meaning that it delays evaluating expressions until their values are needed.

  • Purely functional language: A purely functional programming language is one that employs a functional programming paradigm. Functions in such a language are pure, have no side effects, and are treated as first-class functions, enabling higher order functions and function composition.

add :: Int -> Int -> Int
add x y = x + y
main :: IO ()
main = print (add 3 4)

Consider the add function in the code above. The function takes two parameters x and y, each of type Int, and returns their sum as an Int. The add function is pure because:

  • It has no side effects, meaning that it does not modify any external state or variables.

  • For the same set of inputs, the function will always produce the same output.

Features

Some key features of Haskell programming language are:

Static type system: Haskell has a strong and static type system that allows detecting type errors at compile-time before the program is actually executed.

Pattern matching: Haskell has a powerful pattern matching system that allows extracting values and maintaining control flow through matching specific patterns against values.

Higher order functions: Haskell functions are first-class functions, meaning that they can be passed as arguments to other functions, returned as results, and stored in data structures.

Concurrency and parallelism: Haskell has built-in support for concurrent and parallel programming.

Limitations

Haskell, like any other programming language, also has some limitations. For instance:

  • Haskell, by its functional nature, can prove to be a bit complex to understand for someone new to programming.

  • Since Haskell is a high-level programming language, it is sometimes slower than low-level programming languages like C and C++.

  • Haskell encourages pure functions and immutability, requiring extra effort to work with mutable states and performance side effects.

Conclusion

Haskell is a powerful programming language that embodies the essence and demonstrates the full potential of the functional programming paradigm. With features like immutability, purity, strong type system, and lazy evaluation, it allows programmers to build safe, scalable, and maintainable applications. The language continues to evolve, thanks to its active and passionate community, and shines in various domains, including formal verification, compiler construction, and academic research.

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