XMG (eXtensible MetaGrammar) is a tool allowing to create linguistic resources, especially TAG grammars. The conception of an XMG grammar consists in a compact description of the grammar trees, which uses abstraction mechanisms. This description, called Metagrammar, is similar to a computer program. The aim of XMG is to generate, using the Metagrammar as input, the grammar which it describes. This operation is called compilation.
The information and resources related to XMG are available at this address: http://xmg.phil.hhu.de/. It is also possible to develop XMG grammars by using the online compiler, available at the same address.