The stack is where everything happens. Arguments to operators are pushed onto the stack, the operator takes these values off the stack, produces the result and pushes it back on the stack. Most operators will optionally take a operand immediately following as a variable name, and use this for one of their arguments instead of the stack.
Most operators are binary, although a few are unary, and there is one tertiary operator.
The first example pushes the numeric literal 1 on the stack, followed by the value of the X variable. Then the value is taken off the stack and written back into X . Note that the result is still put on the stack though. The last two examples use the increment operator instead. Go to the first , previous , next , last section, table of contents .