\rail@t{lbrace} \rail@t{ rbrace} \rail@p{-a -h} \rail@i{1}{ stmt : stmtexpr ';' | whilestmt | block | ifstmt ; whilestmt : 'while' '(' expr ')' 'stmt' ; block : lbrace stmtlist rbrace ; } \rail@i{2}{ stmtlist0 : stmt * ; stmtlist1 : stmt + ; ifstmt : 'if' '(' expr ')' \\ stmt ( 'else' stmt ) ? }