Parsing -- a framework for building parsers

Description

Parsing is a package the provides a framework for building parsers. It introduces Parser, a type of function that parses a sequence of tokens, and Analyzer, a type of function that accepts input for the parser in its original form and separates it into a stream of tokens. A parser can be combined with an analyzer: see Parser : Analyzer, to produce a complete system for accepting input and parsing it.

See the package Classic for a good example of the use of this framework.

Author

Daniel R. Grayson <[email protected]>

Version

This documentation describes version 1.0 of Parsing.

Source code

The source code from which this documentation is derived is in the file Parsing.m2.

Exports

Types
- Analyzer -- the class of all lexical analyzers
- Parser -- the class of all parsers
Functions and commands
- andP -- parser conjunction
- charAnalyzer -- a lexical analyzer that provides characters from a string one at a time
- constParser -- produce a parser that accepts a fixed string, one character at a time
- deadParser -- a parser which accepts no tokens and is not in a terminal state
- futureParser -- forward reference to a parser not defined yet
- letterParser -- a parser that accepts a single letter and returns it
- NNParser -- a parser that accepts (and returns) a natural number, one character at a time
- nonspaceAnalyzer -- a lexical analyzer that provides non-white-space characters from a string one at a time
- nullParser -- a terminal parser that returns the value nil
- optionalSignParser -- a parser that accepts an optional plus sign or minus sign
- optP -- making a parser optional
- orP -- parsing alternatives
- QQParser -- a parser that accepts (and returns) a rational number, one character at a time
- terminalParser -- produce a parser in a terminal state
- ZZParser -- a parser that accepts (and returns) an integer, one character at a time
Methods
- * Parser -- repetition of a parser
- + Parser -- repetition of a parser at least once
- "Parser @ Parser" -- see andP -- parser conjunction
- "Parser @ String" -- see andP -- parser conjunction
- "String @ Parser" -- see andP -- parser conjunction
- Function % Parser -- transform the value returned by a parser
- "Parser | Parser" -- see orP -- parsing alternatives
- "Parser | String" -- see orP -- parsing alternatives
- "String | Parser" -- see orP -- parsing alternatives
- Parser : Analyzer -- combine a parser with a lexical analyzer to make a complete system
Symbols
- nil -- a symbol a parser may return to indicate acceptance of the empty string of tokens

For the programmer

The object Parsing is a package.