Efficient and Comfortable Error Recovery in Recursive Descent Parsers

This paper describes the interesting features of the recursive descent parser generator Ell from the user’s point of view. Some of the interesting implementation aspects are discussed. The generated parsers are extremely fast and run at speed of 55,000 tokens per second or 900,000 lines per minute on a MC 68020 processor. The outstanding features of Ell are the L-attribution mechanism, its ability to handle non LL(1) grammars, and its comfortable error handling, which includes error reporting, recovery, and repair.