Search results
Results from the WOW.Com Content Network
Semantic parsing is the task of converting a natural language utterance to a logical form: a machine-understandable representation of its meaning. [1] Semantic parsing can thus be understood as extracting the precise meaning of an utterance.
Some parser generators, such as the byacc-derived BtYacc ("Backtracking Yacc"), give the generated parser the ability to try multiple attempts to parse the tokens. In the problem described here, if an attempt fails because of semantic information about the identifier, it can backtrack and attempt other rules. [3]
When a token class represents more than one possible lexeme, the lexer often saves enough information to reproduce the original lexeme, so that it can be used in semantic analysis. The parser typically retrieves this information from the lexer and stores it in the abstract syntax tree. This is necessary in order to avoid information loss in the ...
However, parser generators for context-free grammars often support the ability for user-written code to introduce limited amounts of context-sensitivity. (For example, upon encountering a variable declaration, user-written code could save the name and type of the variable into an external data structure, so that these could be checked against ...
A semantic definition of a programming language, in our approach, is founded on a syntactic definition. It must specify which of the phrases in a syntactically correct program represent commands , and what conditions must be imposed on an interpretation in the neighborhood of each command.
Computational semantics is the study of how to automate the process of constructing and reasoning with meaning representations of natural language expressions. [1] It consequently plays an important role in natural-language processing and computational linguistics.
While useful, pure parser generators only address the parsing part of the problem of building a compiler. Tools with broader scope, such as PQCC, Coco/R and DMS Software Reengineering Toolkit provide considerable support for more difficult post-parsing activities such as semantic analysis, code optimization and generation.
Part-of-speech tagging (which resolves some semantic ambiguity) is a related problem, and often a prerequisite for or a subproblem of syntactic parsing. Syntactic parses can be used for information extraction (e.g. event parsing, semantic role labelling, entity labelling) and may be further used to extract formal semantic representations.