Programming language theory is a branch of computer science that deals with the study of the design, implementation, and use of programming languages. It is concerned both with the theoretical design of programming languages and with the practical methods of implementing them in a given computing environment. It originated as a branch of mathematics but has since evolved into its own discipline, and its foundations lie in the contributions of Alan Turing, Alonzo Church, and the founders of mathematical logic.
Programming language theory is a broad topic, and its main components can be divided into the following categories:
Syntax – This deals with the structure of the language and how its elements are constructed and organized, including the way in which different elements interact. It covers the rules by which characters or sequence of characters are interpreted as valid commands in the language.
Semantics – This deals with the meaning of the commands in the language and how they are expressed and understood. It covers the way in which the language is interpreted by the computer and the way in which commands interact to create a logical output.
Implementation – This deals with the way in which a specific programming language is expressed in a given computing environment. This includes both the way in which the language is compiled or interpreted, and the methods used to contribute to a successful compile or interpretation.
Programming language theory also deals with formal models of computation, making use of a variety of mathematical techniques including set theory, graph theory, and logical calculi.
The discipline has seen a marked growth in recent years due to the emergence of new programming paradigms, such as object-oriented and functional programming. This growth has resulted in the development of new language designs and methodologies, such as scripting languages, dynamic typing, and garbage collection.
