English version
Accueil     À propos     Téléchargement     Ressources     Contactez-nous    

Ce site est rarement mis à jour. Pour les informations les plus récentes, rendez-vous sur le nouveau site OCaml à l'adresse ocaml.org.

Browse thread
[ANNOUNCE] Alpha release of Menhir, an LR(1) parser generator for ocaml
[ Home ] [ Index: by date | by threads ]
[ Search: ]

[ Message by date: previous | next ] [ Message in thread: previous | next ] [ Thread: previous | next ]
Date: 2005-12-12 (17:58)
From: Francois Pottier <Francois.Pottier@i...>
Subject: [ANNOUNCE] Alpha release of Menhir, an LR(1) parser generator for ocaml

Dear Caml users,

We are proud to announce the first release of Menhir. Menhir compiles LR(1)
grammar specifications to OCaml code.

Menhir is 90% compatible with ocamlyacc. That is, existing ocamlyacc grammar
specifications are accepted and compiled by Menhir; the resulting parsers run
and produce correct parse trees, except they produce incorrect position
information, because none of the functionality of module Parsing is
supported. Porting a grammar specification from ocamlyacc to Menhir requires
replacing all calls to the Parsing module with new keywords.

Why switch from ocamlyacc to Menhir? In short,

 * Menhir offers parameterized nonterminal symbols as well as a library of
   standard definitions, including options, sequences, and lists. It also
   offers limited support for EBNF syntax.

 * ocamlyacc accepts LALR(1) grammars; Menhir accepts LR(1) grammars, thus
   avoiding certain artificial conflicts.

 * Menhir explains conflicts in terms of the grammar, not (only) in terms of
   the automaton.

 * Menhir allows grammar specifications to be split over multiple files. It
   also allows several grammars to share a single set of tokens.

 * Menhir produces reentrant parsers.

 * Menhir is able to produce parsers that are parameterized by Ocaml modules.

 * ocamlyacc requires semantic values to be referred to via keywords: $1, $2,
   and so on. Menhir allows semantic values to be explicitly named.

 * Menhir's error and warning messages are usually more numerous and better
   than ocamlyacc's.

A more detailed comparison between ocamlyacc and Menhir appears in Menhir's

This is an ALPHA-quality release, so there certainly remain a lot of bugs
to iron out. Nevertheless, we encourage intrepid testers to have a look
and send suggestions and bug reports our way. Thanks for your attention!

Menhir requires ocaml 3.09. The source distribution and the documentation can
be found at


François Pottier and Yann Régis-Gianas