Haskell Article

Introduction

Haskell is a statically types, purely functional programming language with type inference and lazy evaluation. Type classes, which enable type-safe operator overloading, originated in Haskell.

Haskell was first introduced in 1990, it was designed by a collection of people including Lennart Augustsson. It is named after logician Haskell Curry.

Haskell is based on the semantics, but not the syntax, of the Miranda programming language, which served to focus the efforts of the initial Haskell working group.

Features

Haskell features consist of:

Syntax
Typeclasses and Polymorphism
Monads and Input/Output
Concurrency
And much more!

Haskell features lazy evaluation, lambda expressions, pattern matching, list comprehension, type classes and type polymorphism. It is purely functional language, which means that functions generally have no side effects. A distinct construct exists to represent side effects, orthogonal to the type of functions. A pure function can return a side effect that is subsequently executed, modeling the impure functions of other languages.

Haskell has a strong, static type system based on Hindley-Milner type inference. Its principal innovation in this area is type classes, originally conceived as a principled way to add overloading to the language, but since finding many more uses.

Pros/Cons

Haskell has its pros and cons:

Pros	Cons
Clean, clear, readable code.	Hard to learn so it has few developers - OO-Programmers have especially a hard time at learning Haskell because it is a Functional programming language.
Lots of libraries.	Libraries are often contain a poor quality of documentation, or are overly-complicated.
New way of looking at problems.	Lazy evaluation which means you cant easily reason about the execution order, in fact, you don't even know whether a certain piece of code actually gets evaluated in a given situation. This means that debugging Haskell requires a different mindset if only because stepping through your code is less useful and less meaningful.
Easy to see why and what the code is doing.	A few clumsy language features are unnecesary for example - record syntax does not introduce a naming scope, so there is no way to have the same record field name in two different types within the same module namespace.
Decent performance and excellent concurrent performance for stuff like web back-end programming (lightweight).	Due to Haskell's purity, you can't use side effects to do things like I/O (input / output), you have to use a monad and "abuse" lazy evaluation to achieve interactivity, and you have to drag the monadic context around anywhere you might want to do I/O.
Type safety is very good (usually above mainstream languages).	Haskell is complicated to get into - There is also a steep learning curve.

Extra Programs

Other Functional Programming Languages - Elixir, Scala, Erlang, Clojure
Package Managers
Back End Web Programming - Node.js, Java, Python, Ruby, Rust
Frameworks
Databases - Oracle, mySQL, MongoDB, PostgreSQL
APIs - REST

Sources

Summary

In conclusion:

Haskell is a very unique programming language. It is also purely functional which makes it hard to learn for people who are used to OO-Principles. Haskell is usually used in back end technologies of big businesses and data. Data analysis is the main strength of Haskell, as well as fast prototyping. Haskell can also be used for web development but there is a scarcity of jobs that involve Haskell. I would recommend Haskell to have a backend language in your arsenal but remember - It is not used much in the real world!