say .parse: '= { 1 + {2 + 3} + 4 };' given grammar hellotanjent { rule TOP { <line> | <line> <TOP> | ';' <TOP> } proto rule line { * } multi rule line:sym<=stmt> { '=' <stmt> ';' } multi rule line:sym<=braces> { '=' <braces> } rule stmt { <expr> <stmt>? } rule expr { \d | <braces> | '+' } rule braces { '{' <stmt> '}' } }