Search results
Results from the WOW.Com Content Network
Deep semantic parsing, also known as compositional semantic parsing, is concerned with producing precise meaning representations of utterances that can contain significant compositionality. [23] Shallow semantic parsers can parse utterances like "show me flights from Boston to Dallas" by classifying the intent as "list flights", and filling ...
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.
It is used to parse source code into concrete syntax trees usable in compilers, interpreters, text editors, and static analyzers. [ 1 ] [ 2 ] It is specialized for use in text editors, as it supports incremental parsing for updating parse trees while code is edited in real time, [ 3 ] and provides a built-in S-expression query system for ...
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 ...
For example, denotational semantics of functional languages often translate the language into domain theory. Denotational semantic descriptions can also serve as compositional translations from a programming language into the denotational metalanguage and used as a basis for designing compilers .
These examples all only require lexical context, and while they complicate a lexer somewhat, they are invisible to the parser and later phases. A more complex example is the lexer hack in C, where the token class of a sequence of characters cannot be determined until the semantic analysis phase since typedef names and variable names are ...
Semantic analysis or context sensitive analysis is a process in compiler construction, usually after parsing, to gather necessary semantic information from the source code. [1] It usually includes type checking , or makes sure a variable is declared before use which is impossible to describe in the extended Backus–Naur form and thus not ...
The following example demonstrates the common case of parsing a computer language with two levels of grammar: lexical and syntactic. The first stage is the token generation, or lexical analysis , by which the input character stream is split into meaningful symbols defined by a grammar of regular expressions .