syntaxes

Syntaxes refer to the sets of rules that govern the structure of expressions in a language or formal system. They determine which sequences of symbols are well formed and how complex expressions can be built from simpler units. Syntaxes are distinct from semantics, which concerns meaning, and from pragmatics, which concerns use and context.

In natural language, syntax describes how words combine into phrases and sentences, creating hierarchical structures such as noun phrases and verb phrases. The study of syntax investigates rules for word order, agreement, subordination, and movement, often represented by parse trees. Different linguistic theories offer varying accounts of how syntax is learned and represented, from traditional grammar to modern computational approaches.

In programming and data formats, syntax defines the allowable arrangement of tokens, keywords, and punctuation. A language’s grammar is often expressed in forms such as BNF or EBNF; parsers use these rules to translate code into executable form or into data structures like abstract syntax trees. Syntax errors arise when input violates the rules, hindering parsing or compilation.

In formal sciences, syntax is analyzed through formal grammars within the Chomsky hierarchy, including regular, context-free, context-sensitive, and recursively enumerable grammars. These classifications relate to the computational resources needed to recognize valid strings.

Applications of syntax include compilers, interpreters, development tools, and data formats such as JSON, XML, and YAML, each imposing precise structural rules that enable reliable parsing and processing.