Editing Theoretical computer science (section)

===Programming language theory and program semantics===
{{main|Programming language theory|Program semantics}}
[[Programming language theory]] is a branch of computer science that deals with the design, implementation, analysis, characterization, and classification of [[programming language]]s and their individual [[Programming language#Elements|features]]. It falls within the discipline of theoretical computer science, both depending on and affecting [[mathematics]], software engineering, and [[linguistics]]. It is an active research area, with numerous dedicated academic journals.

In [[programming language theory]], '''semantics''' is the field concerned with the rigorous mathematical study of the meaning of [[programming language]]s. It does so by evaluating the meaning of [[programming language syntax|syntactically]] legal [[String (computer science)|strings]] defined by a specific programming language, showing the computation involved. In such a case that the evaluation would be of syntactically illegal strings, the result would be non-computation. Semantics describes the processes a computer follows when executing a program in that specific language. This can be shown by describing the relationship between the input and output of a program, or an explanation of how the program will execute on a certain [[computer platform|platform]], hence creating a [[model of computation]].