The Object Management Group (OMG) is pursuing its new Model-Driven Architecture (MDA) strategy. The Meta-Object Facility (MOF) is an important technology to support the MDA, both as a general modelling technique but also specifically to support the definition of other modelling systems. The OMG has standardised the generation of repositories based on MOF models. Anti-Yacc is a tool that can be used to extract the contents of a MOF-based repository in textual form. The Anti-Yacc tool takes as input the specification of grammar rules, lexical rules, and MOF-extraction rules, from which a Java program is generated to extract the contents of a MOF-based repository on demand. Anti-Yacc can be used for code generation, interfacing with legacy syntaxes, and general report writing.