Rewrite rule

For rewriting system in computer science, see Rewriting. For rewriting rule in a formal grammar, see Production (computer science). For the use of "rewrite rules" in web servers, see rewrite engine.

In linguistics, a rewrite rule for natural language (phrase structure rule, analog of production rules in formal grammars) in generative grammar is a rule of the form A → X where A is a syntactic category label, such as noun phrase or sentence, and X is a sequence of such labels and/or morphemes, expressing the fact that A can be replaced by X in generating the constituent structure of a sentence.

Example:

S → NP VP
Which means: Sentence consists of Noun Phrase followed by Verb Phrase.

Rewrite rules underlie rewriting systems; there are many different varieties of rewriting systems that are commonly studied.

See also

• Phonological rule
• Transformational grammar