# Grammatical Framework

## Version 2.8

July 8, 2007.

Documentation | Download | Developers | Changes | QuickStart | Tutorial | Libraries | Examples | NumeralDemo | LetterDemo

## News

August 31, 2007. GF Graduate Course organized by GSLT: first module September 13-14 in Gothenburg.

July 8, 2007. GF 2.8 released. Some highlights:

- Resource Grammar Library v 1.2: synopsis.
- New version of tutorial, now with exercises and also as a pdf file,
- new speech formats
- better semantics of `variants`
- lots of bug fixes

News before 2.7.

## What is GF?

The Grammatical Framework (=GF) is a grammar formalism based on type theory. It consists of

- a special-purpose programming language
- a compiler of the language
- a generic grammar processor

The compiler reads GF grammars from user-provided files, and the generic grammar processor performs various tasks with the grammars:

- generation
- parsing
- translation
- type checking
- computation
- paraphrasing
- random and exhaustive generation
- syntax editing

GF particularly addresses four aspects of grammars:

- multilinguality (parallel grammars for different languages)
- semantics (semantic conditions of well-formedness, semantic properties of expressions)
- modularity and grammar engineering
- reuse of grammars in different formats and as software components

GF provides an easy way to experiment with grammars written in different formats, including the ubiquitous BNF and EBNF formats. The GF compilation chart gives a summary of the supported input and output formats (the nodes in ellipses).
For instance, if you want to create a finite-state automaton in the HTK SLF format (to use for speech recognition), all you have to do is to write an EBNF grammar in a file `foo.ebnf` and type

      echo "pg -printer=slf" | gf foo.ebnf

## License

GF is open-source software licensed under GNU General Public License (GPL).

The are licensed under GNU Lesser General Public License (LGPL).

## Examples and demos

Numeral translator: recognizes and generates numbers from 1 to 999,999 in 80 languages. (The link goes to a live applet, which requires Java 1.5 plugin. Here is an example, which does not require the plugin.)

Letter editor: write simple letters in English, Finnish, French, Swedish, and Russian with a few mouse clicks.

Demo film of a multimodal dialogue system built with embedded grammars.

Resource grammar library: basic structures of ten languages (Danish, English, Finnish, French, German, Italian, Norwegian, Russian, Spanish, Swedish). Resource grammars can be used as libraries for writing GF applications, but they can also be useful for language training.

## Executable programs

GF is available for several platforms: Linux, Mac OS X, Microsoft Windows, and Sun OS. To get GF, go to the Download Page (at SourceForge).

## Quick start

When you have downloaded and installed GF, you can try one of the quick start examples.

## Source code

The main part of GF is written in Haskell.

The platform-independent graphical user interface is written in Java.

The Download Page (at SourceForge) gives links to source and binary packages, as well as information on compiler requirements.

The publicly accessible Darcs repository has the latest sources and documents.

For Java programmers: GF grammars can be embedded in Java programs by using the Embedded GF Interpreter.

## Documents

See the Documentation page.

## Projects and events

- TALK = Tools for Ambient Linguistic Knowledge. GF is used in implementing multimodal and multilingual dialogue systems.
- KeY project on Integrated Deductive Software Design. GF is used for authoring informal and formal specifications. More details on the GF application here.
- WebALT, Web Advanced Learning Technologies. GF is used as for generating multilingual teaching material in mathematics.
- Project Efficient at Tudor Institute, Luxembourg, "atelier de prototypage de transactions d'e-commerce". GF is used as an authoring tool for business models.
- An introductory course on GF was given at the ESSLLI summer school in Vienna 2003.

  ## Miscellaneous

- Gramlets: GF grammars compiled to Java applets.
- GFCC: report on a compiler from a fragment of C to JVM, written in GF. The compiler source code can be found in the directory `examples/gfcc` in the GF grammar library (see GF download page).
- An early version of the GF Home Page last updated for GF, Version 1.2, 2003.
- The original GF Xerox Home Page with the oldest releases of and documents on GF, up to Version 0.54, 1999, does not seem to exist any more.
- Earlier application: Natural-Language Interface to the proof editor Alfa.
- The BNF Converter. A GF spin-off customized for the description of programming languages.
- The Functional Morphology project. Creating infrastructure for GF and other linguistic applications.

## Authors

The Languge Technology Group. More details on the Authors and Acknowledgements page.

## Implementation project

Want to become a GF developer? Contact Aarne Ranta. Or just get the sources and start hacking.

And register to the GF User's Mailing List!

Last modified by Aarne Ranta, December 22, 2005.