[Logo]  DyALog

DyALog is an environment for building tabular unification-based parsers and programs.

Tabulation means that traces of computation are tabulated in order to share common sub-computations and detect (most kinds of) loops. By keeping traces of computations, it is also possible, after a computation, to extract, as a shared forest, the set of all successful proofs or parse trees. These characteristics are especially useful to handle highly recursive and ambiguous grammars for Natural Language.


Some parsers built with DyALog may be tried on line, including a large coverage hybrid TIG/TAG French grammar derived from a metagrammar.

Copyright and License

DyALog is copyrighted 1999 - 2004 Institut National de Recherche en Informatique et Automatique (INRIA) and its sources may be freely distributed under the terms of its license.


The current version 1.10.4 runs under Linux on i*86 architectures.

It requires Perl 5, gcc, and Boehm's Garbage Collector (> version 6.1).


The complete DyALog distribution resides on ftp.inria.fr and can be accessed by anonymous FTP:
        host:       ftp.inria.fr (
        directory:  INRIA/Projects/Atoll/Eric.Clergerie/DyALog
or through the following WEB site


DyALog may be used just to evaluate standard PROLOG programs but its main finality is to design efficient parsers for several grammatical formalisms used in Computational Linguistics:

DyALog provides a rich subset of all builtins provided by most PROLOG systems (Input/Output, Arithmetic, Term Comparison, ...) and may be interfaced with C to inherit C libraries API.

DyALog also provides several extensions to the usual PROLOG syntax and data structures to ease grammar development, including:

DyALog provides many useful features to design more efficient parsers, including:


An English documentation for DyALog (HTML,PDF) exists but is still largely incomplete and outdated.

Several papers are available that partially describe the functionalities of DyALog: [TALN02] (in French), [TAPD98] (in English) [ATALA99] (in French), [PhD93] (in French)

Bug Reports and User Feedback

Send your bug reports and suggestions by E-mail to
Eric De la Clergerie<Eric.De_La_Clergerie@inria.fr>

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