Meaning of context-free grammar | Babel Free

Definitions

A formal grammar in which every production rule is such that the left-hand side is exactly one non-terminal symbol and the right-hand side is zero or more terminal symbols and/or nonterminal symbols.

Equivalents

Examples

“It remains to explain⟳ one final concept, namely what a context free language is. (Don’t get⟳ confused: we’ve told you what a context free grammar is, but not what a context free language is.) Quite simply, a context free language is a language that can be generated by a context free grammar. Some languages are context free, and some are not. For example, it seems plausible that English is a context free language. That is, it is probably possible to write⟳ a context free grammar that generates all (and only) the sentences that native speakers find⟳ acceptable. On the other hand, some dialects of Swiss-German are not context free. It can be proved mathematically that no context free grammar can generate⟳ all (and only) the sentences that native speakers of Swiss-German find⟳ acceptable.¹ So if you wanted to write⟳ a grammar for such dialects, you would have⟳ to employ⟳ additional grammatical mechanisms, not merely context free rules.”

CEFR level