Abstract: The ATLAS-EBNF grammar not only introduces more operators than common EBNF, but defines precedence between operators. Owing to its particularity, we can not design a parser for ATLAS-EBNF directly, so a grammar transformation is needed. A transformation technique was proposed based on super grammar and the proof of its correctness was given. The transformation technique was applied and verified in our project for the implement of ATLAS.

Key words: BNF, EBNF, extended grammar, grammar transformation, super grammar