5 Jan
2014
5 Jan
'14
8:40 p.m.
I use an RPM calculator and have for decades. My big
gripe is that my
HP-16 doesn't tell me how deep the stack currently is and doesn't err
out when I try to pop the stack beyond what's been pushed. Nor do they
tell me when I've tried to push something beyond the T register.
Of course, infix calculators usually don't tell you that the cell that
you're recalling doesn't contain anything.
Either deficiency could have been solved with just a simple flag that
distinguishes between a register/cell that's empty or one that contains
data.
Has this been remedied in any of the newer RPN calculators?
Yes (if I understnad what you are asking for). The RPL machines
(HP28,48,49,50) have an arbitrarily large stack, limited only by
avaialble memeory. And an empty stack is just that, it is not full of
zeors. So stack underflow (or 'Too few arguments;) is an error.
Operators work like they do in Forth, say. They pop the arguemtns froim
ther stack and push the result(s). Oh, and in RPL, the stack doesn't
just cotnain real numbers. It can also contain strings, complex numbers,
vectors, matrices, algebraic expressions, lists (of anything), programs (!),
etc.
-tony