Grammar re;
Lexer

        //alt1 a = '';
        //alt2 a = 'a' - 'a';
        //alt3 a = a;
        //alt4 a = b; b = a;
        //alt5 a = fail;
        //alt6 a = 'a'; i = 'i';
        //alt7 a = '' Lookahead 'a';
        //alt8 a = 'a';

Parser
//alt8 Ignored fail;
t = a;