Translator Class – Data Member Changes

I decided to rename the data member in the Translator to make more sense. The rpn_list will simply be named output. The op_stack will actually be holding more than just operators (as will be seen, functions and array will be placed on this stack also). Calling it an “operator” stack is not accurate. The operand_stack also will be holding more than strictly operands, though technically “operand” is correct (operands of an operator could be the result of another operator). The tokens placed in this stack will be “operands” to operators, but could be operands of operators.

I wanted to come up with better names (“op” is ambiguous and “operator” and “operand” are too similar). It would be a bonus if they had the same number of characters. Therefore, I came up this the name hold_stack for operators and other tokens on “hold” or pending to be placed in the output list. The other stack will named done_stack for tokens that are “done” being processed and have been placed into the output list.  By the way, this parallels the result stack at run-time, which will hold values of operands and results of operators (to be used as operands for the next operator or command).

Translator – Operator Precedence

The precedence member needs to be added to the Table, which the Translator will use to rearrange the input to the output RPN list. After considering the operator precedence in several BASICs and in C, the operator precedence that will be used for this project is (from highest to lowest):

^             (exponentiation)
-             (negation)
*, /          (multiplication, division)
\             (integer division)
MOD           (modulus)
+, -          (addition, subtraction)
<, >, <=, >=  (relational operators)
=, <>         (equivalence operators)
NOT           (logical not/1's compliment)
AND           (logical/bit wise and)
XOR           (logical/bit wise exclusive or)
OR            (logical/bit wise or)
IMP           (implication)
EQV           (equivalence)