Even faster generalized LR parsing

We prove a property of generalized LR (GLR) parsing - if the grammar is wit hout right and hidden left recursions, then the number of consecutive reduc tions between the shifts of two adjacent symbols cannot be greater than a c onstant. Further, we show that this property can be used for constructing a n optimized version of our GLR parser. Compared with a standard GLR parser, our optimized parser reads one symbol on every transition and performs sig nificantly fewer stack operations. Our timings show that, especially for hi ghly ambiguous grammars, our parser is significantly faster than a standard GLR parser.