Chart parser

A chart parser is a type of parser commonly used for natural languages that uses a data-driven approach based on a set of grammatical rules and a dictionary with each of the possible grammatical senses of each word indicated. There may also be a set of probabilities obtained from analysis of a text corpus.

A systematic search is used to explore the space of possible parses of the input string, and a data structure called a "chart" is used to eliminate backtracking and prevent a combinatorial explosion.

Types of Chart Parsers

• A common approach is to use a variant of the Viterbi algorithm.
• The Earley parser is a type of chart parser mainly used for parsing in computational linguistics, named for its inventor.
• Another chart parsing algorithm is the Cocke-Kasami-Younger (CKY) algorithm.

Chart parsers can also be used for parsing computer languages. Earley parsers in particular have been used in compiler compilers such as the Accent programming language

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where their ability to parse using arbitrary Context-free grammars eases the task of writing the grammar for a particular language. However their lower efficiency has led to people avoiding them for most compiler work.

See also:

• Brute force search
• Dynamic programming

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