Which of the following LR parsers is the most powerful (handles the largest class of context-free grammars)?
CLR(1) maintains distinct lookahead contexts for every item, making it strictly more powerful than LALR(1), SLR(1), and LR(0).
LALR(1) parsing tables are constructed by merging states of a CLR(1) parser that have:
LALR(1) reduces CLR(1) table size by combining states that share identical LR(0) item cores, merging their lookahead sets.
Merging states with identical LR(0) cores in a CLR(1) parser to create an LALR(1) parser can NEVER introduce which type of conflict?
Merging states with identical cores cannot introduce Shift-Reduce conflicts (if an S/R conflict wasn't present in CLR(1)). However, it CAN introduce new Reduce-Reduce conflicts.
In bottom-up shift-reduce parsing, a 'Handle' is defined as:
A handle is a substring that matches a production RHS and whose reduction step by step reverses a valid rightmost derivation.
Which grammar rule transformation eliminates common prefixes to enable predictive top-down parsing?
Left factoring rewrites rules with common prefixes (e.g. A -> alpha beta1 | alpha beta2 into A -> alpha A') so the parser can defer choice until lookahead reveals the suffix.