gistfile1.txt

Sum          = a:Product                   { PushStack(a); }
                      ( - "+" - b:Product  { ReplaceStackTop([TQNodeOperator nodeWithType:kTQOperatorAdd      left:StackTop right:b]); }
                      | - "-" - b:Product  { ReplaceStackTop([TQNodeOperator nodeWithType:kTQOperatorSubtract left:StackTop right:b]); }
                      )*                   { $$ = PopStack(); }

Product      = a:Variable                  { PushStack(a); }
                       ( - "*" - b:Product { ReplaceStackTop([TQNodeOperator nodeWithType:kTQOperatorMultiply left:StackTop right:b]); }
                       | - "/" - b:Product { ReplaceStackTop([TQNodeOperator nodeWithType:kTQOperatorDivide   left:StackTop right:b]); }
                       )*                  { $$ = PopStack(); }

Equation     = a:Sum                       { PushStack(a); }
               ( - "<" -  b:Equation       { ReplaceStackTop([TQNodeOperator nodeWithType:kTQOperatorLesser         left:StackTop right:b]); }
               | - ">" -  b:Equation       { ReplaceStackTop([TQNodeOperator nodeWithType:kTQOperatorGreater        left:StackTop right:b]); }
               | - "<=" - b:Equation       { ReplaceStackTop([TQNodeOperator nodeWithType:kTQOperatorLesserOrEqual  left:StackTop right:b]); }
               | - "=>" - b:Equation       { ReplaceStackTop([TQNodeOperator nodeWithType:kTQOperatorGreaterOrEqual left:StackTop right:b]); }
               | - "==" - b:Equation       { ReplaceStackTop([TQNodeOperator nodeWithType:kTQOperatorEqual          left:StackTop right:b]); }
               | - "!=" - b:Equation       { ReplaceStackTop([TQNodeOperator nodeWithType:kTQOperatorInequal        left:StackTop right:b]); }
               )*                          { $$ = PopStack(); }