Section: Software

Tools and resources for Meta-Grammars

Participant : Éric Villemonte de La Clergerie [maintainer] .

mgcomp , MgTools , and FRMG on INRIA GForge: http://mgkit.gforge.inria.fr/

DyALog (cf.  5.2 ) has been used to implement mgcomp , Meta-Grammar compiler. Starting from an XML representation of a MG, mgcomp produces an XML representation of its TAG expansion.

The current version 1.5.0 is freely available by FTP under an open source license. It is used within ALPAGE and (occasionally) at LORIA (Nancy) and at University of Pennsylvania.

The current version adds the notion of namespace, to get more compact and less error-prone meta-grammars. It also provides other extensions of the standard notion of Meta-Grammar in order to generate very compact TAG grammars. These extensions include the notion of Guarded nodes, i.e. nodes whose existence and non-existence depend on the truth value of a guard, and the use of the regular operators provided by DyALog on nodes, namely disjunction, interleaving and Kleene star. The current release provides a dump/restore mechanism for faster compilations on incremental changes of a meta-grammars.

The current version of mgcomp has been used to compile a wide coverage Meta-Grammar FRMG (version 2.0.1) to get a grammar of around 200 TAG trees [129] . Without the use of guarded nodes and regular operators, this grammar would have more than several thousand trees and would be almost intractable. FRMG has been packaged and is freely available.

To ease the design of meta-grammars, a set of tools have been implemented, mostly by Éric de La Clergerie, and collected in MgTools (version 2.2.2). This package includes a converter from a compact format to a XML pivot format, an Emacs mode for the compact and XML formats, a graphical viewer interacting with Emacs and XSLT stylesheets to derive HTML views. A new version is under development to provide an even more compact syntax and some checking mechanisms to avoid frequent typo errors.

The various tools on Metagrammars are available on INRIA GForge.