Constraint-based grammar

Constraint-based grammars can perhaps be best understood in contrast to generative grammars. A generative grammar lists all the transformations, merges, movements, and deletions that can result in all well-formed sentences, while constraint-based grammars, take the opposite approach, allowing anything that is not otherwise constrained. "The grammar is nothing but a set of contraints that structures are required to satisfy in order to be considered well-formed."^[1] "A constrain-based grammar is more like a data base or a knowledge representation system than it is like a collection of algorithms."^[2]

Examples of such grammars include^[3]

• the non-procedural variant of Transformational Grammar of Lakoff, that formulates constraints on potential tree sequences,
• Johnson and Postal’s formalization of Relational Grammar (1980), GPSG in the variants developed by Gazdar et al. (1988), Blackburn et al. (1993) and Rogers (1997),
• LFG in the formalization of Kaplan (1995) and
• HPSG in the formalization of King (1999).

References

1. ↑ Pollard, Carl. "The nature of constraint-based grammar" (PDF). 11th Pacific Asian conference on language, information and computation. 
2. ↑ Pollard, Carl. "The nature of constraint-based grammar" (PDF). 11th Pacific Asian conference on language, information and computation. 
3. ↑ Müller, Stefan (2016). Grammatical theory: From transformational grammar to constraint-based approaches. Berlin: Language Science Press. pp. 490–491.