State and backtracking

gistfile1.6pl

#!/usr/bin/env perl6

grammar Tracker {
    regex TOP {
        :my %*QUOTE_TRACKER;
        Beginning
        [ <quote> || .*! ]
        End { say "failure" if %*QUOTE_TRACKER<inQuote> == True }
    }

    regex quote {
        \" { say "enter quote"; %*QUOTE_TRACKER<inQuote> = True }
        .*?
        \" { say "exit quote"; %*QUOTE_TRACKER<inQuote> = False }
    }
}

Tracker.parse("Beginning\"stuff\@End");