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XLFG version 9.16.2

Author: Lionel Clément -- University Bordeaux -- LaBRI

XLFG is a fast, accurate deep parser for LFG grammar. These outputs are phrase structures, predicate-argument structures and predicate-thematic relationships.

The typical XLFG applications are

  • Syntax courses
  • Research and education in Linguistics
  • Research and education in Computational Linguistics
  • Computational Linguistics projects
Lionel Clément - XLFG Copyright 2014-2025 LaBRI, CNRS (UMR 5800), the University of Bordeaux, and the Bordeaux INP

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Terms and conditions of use of the site XLFG

XLFG has been designed to allow the sharing of grammars between multiple users (students, teachers, lecturers, researchers, etc.). Nevertheless, it is not designed to backup data. We are not responsible for any loss of work. To make sure work and data is properly saved, a variety of alternative methods are readily available.

XLFG is often used for exams and tutorials. While we endeavor to do the utmost to prevent server interruptions, we disavow any liability for problems resulting from the use of this web site during exams or tutorial sessions.

XLFG has been designed with the field of linguistics in mind. The comments and opinions on the sentences are those of the author alone and do not necessarily reflect those of the XLFG operator.

We reserve the right to terminate any account and remove all contents associated with it at any moment.

Lionel Clément - XLFG Copyright 2014-2025 LaBRI, CNRS (UMR 5800), the University of Bordeaux, and the Bordeaux INP

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Last Updates

  • User interface modifications (in green)
  • Software modifications (in blue)
  • Internal modifications (for developer) (in red)
  • 9.16.2 (minor - february 2025 - revision 39197)
    • New server.
  • 9.16.1 (minor - december 2022 - revision 38559)
    • Security Update and new IP server.
  • 9.16.0 (minor - december 2021 - revision 37829)
    • A new tab named "Error" will be added to output from where you will be able to see warning and error messages.
    • New print button on each parse result.
    • New links on functional-structure results.
    • SUBCAT keyword on F-structures deprecated. Replaced with PRED feature.
    • LEXEME keyword on F-structures deprecated for prefixes and suffixes lexemes. Replaced with PRED feature.
    • The obsolete notation for optional grammatical is deprecated. [X.x] replaced with [X].x
    • "_unknown_word_" and "_this_" replace the deprecated notations _UNKNOWN_ and _THIS_.
    • Bug fixed on Extended Coherence test.
    • Renaming C++ classes and attributes.
    • Modifications on internal Feature-structure C++ representation.
    • "_unknown_word_" and "_this_" are new keywords; no longer lexical entries.
    • New unification algorithm.
    • New extended coherence algorithm.
    • More robust serialization routines for bitset comparison.
  • 9.15.5 (patch - november 2021)
    • Uniq operator modified.
    • Uniq operator calculated .
    • Optimization: flags type limited to 20 bis.
  • 9.15.4 (patch - november 2021)
    • Improvement of presentation of partial phrases as trees.
    • Improvement of graphic presentation of Constituent-Structures as CFG.
    • Improvement of graphic presentation of of Phrase lattice.
    • Bug fixed on compact presentation of Functional-Structures.
  • 9.15.3 (patch - november 2021)
    • The obsolete version of XLFG is no longer available.
    • The evaluation of lexical equations are made on the local f-structures before the evaluation of the embedded f-structures.
  • 9.15.2 (patch - october 2021)
    • Rewriting some exception messages.
    • Focus only the local functional equations into the selected node.
    • Draw all Functional Equations -> Draw syntactical and lexical Functional Equations
    • The exportation of a version no longer erases the output panel.
    • Test more unification failure.
  • 9.15.1 (patch - october 2021)
    • Renumber the co-indexes f-structures.
    • Increase from 64 to 128 the number of available atoms.
  • 9.15.0 (minor - october 2021)
    • Additing a new equation: let <id> in ↓i <stm>
      The let operator will quantify on each ↓i before the evaluation of the statement <stm>
      It is necessary when ↓i is ambiguous and is present in several instances into <stm>, to prevent all the combination.
      Exemple:
      let prep_phrase in ↓2
        (↑ (prep_phrase PCASE)) = prep_phrase;
  • 9.14.2 (patch - october 2021)
    • Show the wrong functional equations.
    • Show SUBCAT focus in equations.
    • Bug in unification process fixed between PRED and SUBCAT.
    • Remove non relevant Functional equations with literals.
    • A self f-structure is ill-formed on a local node while a local statement fails.
    • A syntactic error throws a FatalErrorException.
  • 9.14.1 (patch - october 2021)
    • Internal bug fixed (bitset to ullong)
  • 9.14.0 (minor - october 2021)
    • The forest link is now available on root note.
    • The details on local FS are now shown.
    • Bugs fixed on unfold/fold shared FS.
  • 9.13.0 (minor - june 2021)
    • In test-suite, selected do not parse this sentence do no loger ovoid the actual grammatical selection.
    • It is possible to see or not the local functional equations locally embedded in FS.
    • Bugs fixed on unfold/fold shared FS.
    • New enumeration on Local linked FS.
  • 9.12.0 (minor - february 2021)
    • change Syntactic functions to grammatical functions.
    • Adding a tab button to insert indentation in the inputs.
    • Bug fixed on let expressions.
    • Bug fixed on evaluation process.
  • 9.11.0 (minor - february 2021)
    • The expression
      with $x in (↑ regexp) [... $dollar x ...]
      is replaced by
      let x in (↑ regexp) [... x ...].
    • Bug fixed on let expressions.
  • 9.10.1 (patch - january 2021)
    • Drawing local functional equations into the F-structures.
    • Bug fixed on path expressions.
    • Bug fixed on difference constraint.
  • 9.10.0 (minor - january 2021)
    • The extended coherence condition stands only for semantic arguments.
  • 9.9.3 (patch - january 2021)
    • Bug fixed on local equations.
  • 9.9.2 (patch - january 2021)
    • Remove a user member or remove a project assignment from a workshop do not longer remove the associated project versions.
    • It is no longer allowed to remove a project when there are still versions of this project.
  • 9.9.1 (patch - january 2021)
    • Allow multiple pointers to the same FS (to be improved)
    • Strip whitespace from the beginning and end of a sentence.
    • Unification before pointing an FS (bug fixed).
  • 9.9.0 (minor - january 2021)
    • Sentences -> Test suite.
    • Parse just one sentence available.
    • Check a word available.
  • 9.8.11 (patch - december 2020)
    • The deprecated Projects>Save version submenu non longer exists.
    • Changing Compact Feature-Structures: No to Uncompact Feature-Structures Yes.
    • Error message telling the user that a sentence cannot be parsed because it contains a word that is not in the lexicon.
    • Bugs fixed in Compact/Uncompact F-Structures data.
  • 9.8.10 (patch)
    • Bugs fixed
      • In $i terms (back-end)
      • In coloration of sentences (front-end)
    • (↑ X) = (↑ Y) equation:
      • If left-hand side (lhs) refers to anonymous variable, creates a pointer lhs => rhs
      • If both lhs and rhs refer to an FS
        1. Unifies
        2. Creates a pointer lhs => rhs
  • 9.8.9 (patch)
    • A bug fixed on constraining equations
    • More explicit Internal error messages
  • 9.8.8 (patch)
    • Various IHM improvements
      • Spelling mistakes and typos
      • Web browsing: you can refresh the page and come back to some of the browsing history
      • Input sentences
        • Coloration
        • Drap and drop to sort sentences
      • Modifications on permissions on the project header
        • Using the original version on hidden mode
        • Using either the original or the copied version on read-only mode
        • A button "Set default grants" was added int the project header
      • Zoom on Argument structure
      • Macro descriptions with '@' sign usable as features values, not only as a feature.

        Example of usage:

        @P: TENSE:present;
        @p: NUMBER:pl;
        @s: NUMBER:sg;
        @_3: PERS:3;
        @_12: PERS:1|2;
        @_3s: @_3, @s;
        @_3p: @_3, @p;
        @_no3s: [@_12] | [@_3p];
        bark verb [PRED:'to_bark', @P, SUBJ:@_no3s];
        barks verb [PRED:'to_bark', @P, SUBJ:@_3s];

Lionel Clément - XLFG Copyright 2014-2025 LaBRI, CNRS (UMR 5800), the University of Bordeaux, and the Bordeaux INP
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In order to run optimally, the site records and saves the cookies from each log-in session.

Your personal information, including your name and e-mail, are not shared with other members of the community without your approbation, but are saved on the server.

The XLFG grammar and lexicon are shared at your discretion.

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