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6.16 LALR(1) Parsing

The (system base lalr) module provides the lalr-scm LALR(1) parser generator by Dominique Boucher. lalr-scm uses the same algorithm as GNU Bison (see Introduction to Bison in Bison, The Yacc-compatible Parser Generator). Parsers are defined using the lalr-parser macro.

Scheme Syntax: lalr-parser [options] tokens rules...

Generate an LALR(1) syntax analyzer. tokens is a list of symbols representing the terminal symbols of the grammar. rules are the grammar production rules.

Each rule has the form (non-terminal (rhs ...) : action ...), where non-terminal is the name of the rule, rhs are the right-hand sides, i.e., the production rule, and action is a semantic action associated with the rule.

The generated parser is a two-argument procedure that takes a tokenizer and a syntax error procedure. The tokenizer should be a thunk that returns lexical tokens as produced by make-lexical-token. The syntax error procedure may be called with at least an error message (a string), and optionally the lexical token that caused the error.

Please refer to the lalr-scm documentation for details.