Grammar development

Grammars form the basis for our factory generation approach. However, in practice it is completely non-trivial to obtain and manage such grammars. The grammar may be included in an international standard, it may be contained in a manual for a proprietary language, or it may be embedded in the source code of existing tools such as compilers or pretty printers [46]. Another problem is that these grammars tend to be huge (several thousands of grammars rules) since they cover various language dialects as well as various local language extensions. From a grammar maintenance perspective, standard LR parsing techniques become unsuitable here, since they tend to generate too many shift/reduce conflicts after each modification to the grammar. We completely depend on the Generalized LR parsing method provided by the ASF+SDF Meta-Environment which is capable of handling arbitrary context-free grammars. It is a research issue how to obtain grammars for languages in a cost-effective manner. We have labeled this activity Computer Aided Language Engineering (CALE) and have a collection of tools for grammar extraction and manipulation.