Langlib

Langlib.Grammars.LR.Equivalence.DPDAToLR.Augmentation

Fresh-start bookkeeping for the DPDA characteristic grammar #

The ordinary characteristic-grammar argument proves Knuth's condition for the grammar itself. CF_grammar.IsLRk, however, deliberately checks the grammar after adjoining one more fresh start symbol. This file discharges the extra start/start and start/ordinary cases. In particular, the wrapper below does not silently omit accept/reduce or accept/shift conflicts.

A generic no-reintroduction invariant #

The outer augmentation is genuinely fresh #

The characteristic start symbol is not reintroduced #

Adding the outer fresh start preserves LR(1) here #

For the reduced characteristic grammar, ordinary LR(1) handle uniqueness already implies the repository's augmented IsLRk 1 predicate.