14 The PARSERGEN Package

defparser

Macro

Summary

Creates a parsing function of the given name for the grammar defined.

Package

parsergen

Signature

defparser name {rule}* => parsing-function
rule ::= normal-rule | error-rule
normal-rule ::= ((non-terminal {grammar-symbol}*) {form}*)
error-rule ::=  ((non-terminal :error) {form}*)

Arguments

name: The name of the parser.

The rules define the productions of the grammar and the associated forms define the semantic actions for the rules.

Values

parsing-function: The symbol name of the parsing function.

Description

defparser creates a parsing function of the given name for the grammar defined. The parsing function is defined as if by:

(defun <name> (lexer &optional (symbol-to-string #'identify))

: The lexer parameter is a function of no arguments that returns two values: the next grammar token on the input and the associated semantic value.
: The optional symbol-to-string function can be used to define a printed representation of the grammar tokens. The function should take a grammar symbol as its single argument and returns an object to be used as a print representation for the grammar token.
: For a full description and examples, see the LispWorks User Guide.