natural language processing Natural language processing (NLP) is a subfield of computer science and especially artificial intelligence. It is primarily concerned with providing computers with the ability to process data encoded in natural language and is thus closely related ...

, deterministic parsing refers to

parsing Parsing, syntax analysis, or syntactic analysis is a process of analyzing a String (computer science), string of Symbol (formal), symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal gramm ...

algorithm In mathematics and computer science, an algorithm () is a finite sequence of Rigour#Mathematics, mathematically rigorous instructions, typically used to solve a class of specific Computational problem, problems or to perform a computation. Algo ...

s that do not backtrack. LR-parsers are an example. (This meaning of the words "deterministic" and "non-deterministic" differs from that used to describe

nondeterministic algorithm In computer science and computer programming, a nondeterministic algorithm is an algorithm that, even for the same input, can exhibit different behaviors on different runs, as opposed to a deterministic algorithm. Different models of computation ...

s.) The deterministic behavior is desired and expected in

compiling In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs tha ...

programming language A programming language is a system of notation for writing computer programs. Programming languages are described in terms of their Syntax (programming languages), syntax (form) and semantics (computer science), semantics (meaning), usually def ...

s. In natural language processing, it was thought for a long time that deterministic parsing is impossible due to ambiguity inherent in natural languages (many sentences have more than one plausible parse). Thus, non-deterministic approaches such as the

chart parser In computer science, a chart parser is a type of parser suitable for ambiguous grammars (including grammars of natural languages). It uses the dynamic programming approach—partial hypothesized results are stored in a structure called a chart a ...

had to be applied. However, Mitch Marcus proposed in 1978 the Parsifal parser that was able to deal with ambiguities while still keeping the deterministic behavior.

References

* Alfred V. Aho,

Stephen C. Johnson Stephen Curtis Johnson (born 1944) is a computer scientist who worked at Bell Labs and AT&T for nearly 20 years. He is best known for Yacc, Lint, spell, and the Portable C Compiler, which contributed to the spread of Unix and C. He has also c ...

, Jeffrey D. Ullman (1975): ''Deterministic parsing of ambiguous grammars.'' Comm. ACM 18:8:441-452. * Mitchell Marcus (1978): A Theory of Syntactic Recognition for Natural Language. PhD Thesis, Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology. Parsing {{Comp-sci-stub

See also

References