I have a question for the traditional RPN users around here. I made the transition from RPL (48G, used for > 10 years) to RPN (35s) 3 months ago and am completely used to my 35s at this point. What I want to know is WHY NOT provide a >4 level stack on modern scientific calculators? What would it hurt? I am completely used to starting from the inside, etc., at this point, so am not crippled by RPN, but I see the 4 level stack limit as being, well, really silly and backward-thinking. Someone please tell me why it's necessary.
I actually have one good example of when RPL kicks the snot outta RPN, for me anyway, and I don't think I'll ever get over this. Say I have a large (even 2-3 lines written) equation with nested radical, whatever nastiness one might have, and want to back-solve for one of the variables in the equation. With RPL, 99.9% of the time, I can back out the variable without re-writing the equation. It's probably been over 10 years since I had to re-write one. This is because I don't have to worry about where the "inside" is with RPL. With RPN, I have no prayer at backing out such a variable because I cannot visualize where the inside *will be* for the re-arranged equation. Not a huge issue, but I find myself writing out an equation every so often that I never would've had to re-write with RPL.
There's also the matter of re-using numerical results. It's extremely common to bring something down from 5-6 levels (or more) up the stack and re-use it in RPL. Of course, unless it's very near the bottom, the number is toast in RPN unless I do the TI-like operation of formally storing it somewhere.
I'd say the limit of 4 registers would seem totally asinine to most folks migrating from other calculators also. Frankly, it *looks* like a glitch or error in 2007. When I first laid hands on a RPN machine last year, I actually thought it was an error until I started doing some research.
So what's the deal? I see no advantage to limiting the stack and can't come up with a scenario for which RPN users would actually be screwed up by the presence of a 5th, etc. stack register.
Some enlightenment would be appreciated.
Edited: 6 Dec 2007, 10:21 p.m.