In this paper we introduce two methods for building LALR parsers for regula
r right part grammars (RRPGs). Both methods build a parser directly from a
grammar, require no extra state or data structure, and can deal with all LA
LR RRPCs.
The first method is quite simple. For almost all LALR RRPGs, including the
majority of grammars with stacking conflicts, parsing actions: are similar
to those of LALR parsers for usual context free grammars. No extra action i
s required to recognize a handle in this case. For other LALR RRPGs, the ri
ght hand side of a production is checked to recognize a handle.
The second method does not require checking of the right hand side of a pro
duction to recognize a handle. Instead, it records the number of conflicts
in LR items and in the stack. Unlike previous methods, our method needs no
extra data structure.