Grammars, syntax, automata theory, regular and context free languages, parsing, recognition, and applications in compilers.
Formal language theory studies sets of strings defined by precise rules, and it provides a mathematical framework for describing syntax, recognition, parsing, and computation.
The chapter begins with grammars and syntax, where formal rules specify how strings are generated from symbols, and these rules make it possible to describe languages independently of informal meaning.
Automata theory is then introduced as the study of abstract machines that recognize languages, including finite automata for regular languages and pushdown automata for context free languages.
Regular and context free languages are studied as two central classes of formal languages, each with its own grammars, automata, closure properties, and limitations.
Parsing and recognition are then discussed as algorithmic problems, where one asks whether a string belongs to a language and, when possible, how its syntactic structure can be recovered.
The final part of the chapter explains applications in compilers, where formal languages are used to describe lexical structure, grammar rules, parsing algorithms, and the early stages of programming language implementation.