We shared on DesignZum some of the best online programming books for our readers. Today we are going to present one of the most advanced, purely functional programming language. In Haskell, "a function is a first-class citizen" of the programming language.
Haskell features lazy evaluation, pattern matching, list comprehension, type classes, and type polymorphism. It is a purely functional language, which means that in general, functions in Haskell do not have side effects. There is a distinct construct for representing side effects, orthogonal to the type of functions. A pure function may return a side effect which is subsequently executed, modeling the impure functions of other languages.
For more information about Haskell, use one of these programming books.
11) WikiBook Haskell