token Num='<number>';
token Plus='+' Minus='-' Star='*' Slash='/' Pow='^';
token LPar='(' RPar=')';
token Whitespace;

skip Whitespace;
right '^';
start calc;

calc: expr;
expr:
  expr '^' expr @binary_expr
| ('-' | '+') expr @unary_expr
| expr ('*' | '/') expr @binary_expr
| expr ('+' | '-') expr @binary_expr
| Num @literal_expr
| '(' expr ')' @paren_expr
;