Yet another parser generator

Zerksis Umrigar <>
7 Aug 1997 15:18:27 -0400

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Yet another parser generator (Zerksis Umrigar) (1997-08-07)
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From: Zerksis Umrigar <>
Newsgroups: comp.compilers
Date: 7 Aug 1997 15:18:27 -0400
Organization: Compilers Central
Keywords: parse, tools, available

This is to announce the first public release of Zyacc: a general-purpose
parser generator that converts a grammar description for an LALR(1)
context-free grammar into a C program to parse that grammar. Zyacc is
largely upward compatible with Yacc and Bison.

Zyacc provides the following enhancements:

      * Supports inherited attributes which can be uniquely evaluated in a
          left-to-right parse.

      * Supports semantic tests which allow the outcome of runtime semantic
          tests to affect parsing decisions.

      * Permits remote interactive debugging of generated parsers either
          by using a textual interface or by using a java-based GUI.
          The debugger allows the setting of breakpoints on any grammar symbol
          and selective display of the current parser state.

      * Allows named attribute variables which make maintaining grammars

      * Can generate its parser description files in HTML which can then be
          viewed using any Web browser.

      * Provides a `%look' directive to check (at parser construction time)
          whether a reduction requires lookahead.

      * Allows multiple start nonterminals and allows a call to the
          parsing function to be made for a particular start nonterminal.

      * It is possible to avoid having types which are only used in
          describing nonterminal semantics written into the generated `.h'

      * Allows multiple-character quoted literal tokens.

      * Allows command-line options to be specified from within the parser

The distribution comes with a Prolog frontend which illustrates the use of
semantic predicates to handle Prolog's dynamic operators. The zyacc home
page also links to a source-to-source profiling tool which is essentially a
Ansi-C frontend which uses semantic predicates for a clean solution to the
problem of parsing typedef-name's in C.

The zyacc homepage is at

The homepage has links to a live demo of the GUI debugger using java

Zyacc can also be ftp'd from:
(about 1.1MB)

which contains full documentation (postscript, html & info), or
(about 650KB)

which contains only the documentation source.

zerksis umrigar

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