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DyALog is an
environment to compile and run logic programs and natural
language tabular parsers for various grammatical formalisms
(DCGs, TAGs, TIGs, RCGs). GForge page., including a
large coverage hybrid TIG/TAG French grammar derived from a
metagrammar.
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:
- DCG (Definite Clause Grammars), traditionally offered by PROLOG systems;
- BMG (Bound Movement Grammars), an extension of DCGs allowing the displacement of constituents;
- TAG (Tree Adjoining Grammars), an elegant and convenient grammatical formalism introduced by Joshi, where elementary partial parse trees are combined by substitution and adjunction to build full parse tree;
- TIG (Tree Insertion Grammars), a variant of TAGs with a simplified adjunction operation (and the possibility for DyALog to automatically identify TIG subparts in TAGs);
- RCG (Range Concatenation Grammars), a very powerful formalism introduced by Pierre Boullier
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:
- (typed) feature structures (TFS) a la Carpenter;
- Finite Sets (or enumeration);
- Hilog pseudo higher order terms;
- Immediate unification;
- Namespaces and modules
DyALog provides many useful features to design more efficient parsers, including:
- different levels of tabulations (none, light, strong).
- user customization of hybrid top-down/bottom-up parsing strategies.
- support for bi-directional parsing strategies, for instance for head-driven parsing strategies.
- (preliminary) support for efficient left-corner parsing strategies.
- new powerful operators such as intersection, extended Kleene star (to build loops), and interleaving (to interleave in any order sequences of constituents). For instance one can write ``(adj @*) ## noun'' to specify (in French), that a noun may be completed on both left or right by any number of adjectives.
- parsing from PROLOG lists or from a word lattices represented by Finite Set Automata (more efficient and useful to handle ambiguous inputs provided by pre-parsing tools).
- filtering for lexicalized parsers to only load grammar fragments anchored by words of the input sentence.
- labeling of constituents for a better reading of the output shared forests.
An English documentation for DyALog ( 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)
- Download DyALog from INRIA GFORGE.
- Please note that for easier installation, you can use the Perl script Alpi (ALPage Installer) typing ./alpi.pl --pkg=DyALog. This single script downloads and installs DyALog.