Incremental Generation of LR Parsers

Implementation of a new compiler usually requires making frequent adjustments to grammar de nitions. An incremental technique for updating the parser tables after a minor change to the grammar could potentially save much computational e ort. More importantly, debugging a grammar is made easier if the grammar is re-checked for correctness after each small change to the grammar. The basic design philosophy of an incremental parser generator, and incremental algorithms for LR(0), SLR(1) and LALR(1) parser generation are discussed in this paper. Some of these algorithms have been incorporated into an implementation of an incremental LALR(1) parser generator. Index Terms { Compilers, Compiler Tools, Program Development Environments, LR Parsing, LALR(1), SLR(1), Incremental Algorithms, Grammar Debugging.