A Context-Free Grammar (CFG) is a formal grammar defined by a set of production rules that describe the syntactic structure of a language. It consists of:
Non-terminal Symbols:
- Represent syntactic categories or abstract symbols. They can be replaced by sequences of other symbols.
Terminal Symbols:
- Represent the actual symbols of the language, such as keywords or constants. Terminals are the end points of the derivation.
Production Rules:
- Define the possible ways in which non-terminals can be expanded into sequences of terminals and/or other non-terminals.
Start Symbol:
- Specifies the non-terminal symbol from which the derivation of the language begins.
A context-free grammar is a concise and formal way to describe the syntax of a programming language or any other formal language. It is used in compiler design, natural language processing, and various areas of theoretical computer science.