Lambda Calculus and functional programming : Using Haskell

This thesis explores the world of Lambda Calculus, functional programming, which is based on Lambda Calculus, and Haskell as an example of a functional programming language. Lambda Calculus is a formal system for denoting something computable. It has played an important part in the development of the mathematical logic and was first introduced by Alonzo Church. Functional programming is one of the paradigms of programming. Other existing paradigms include imperative and object-oriented ones. Functional programming influenced languages from other paradigms, languages like C++ and Java have functional features added in the latest revisions. The aim of the thesis was to learn in which tasks functional programming is favorable. When Haskell would be preferable to other possible languages, or when some specific task should be performed using functional features and thus a language with the functional features is preferable. Several small programs were written in Haskell, Java and Python and then their performance got measured. The functional approach was used in Java and Python where it was considered more concise. Also, some subjective qualities like difficulty of writing or readability of code of programs were evaluated. The conclusion of research conducted showed that functional programming provides considerable amount of utility. However, using the purely functional approach, namely Haskell, is too restricting. For maximal efficiency mixed languages that were developed with the functional features as one of the core components like Scala should be used if functional features are required for the task at hand