RPL (now that I know what that means!)
Message #10 Posted by Ellis Easley on 17 Aug 2002, 5:18 p.m.,
in response to message #9 by Karl Schneider
I've had a 48SX since it was current and added 48GX and 49G when I found them discounted. I never got comfortable with them until recently. What actually got me started was when I found I could write my own graphing programs on the 38G, with its limited programming language. I decided to "port" them to the 49G, where I first had to sort out "RPN vs. Algebraic" and then come to terms with user RPL. Then I wanted to see what the relative speed of the 48GX and 48SX was and easily moved my programs from the 49G to them. I am now quite comfortable with user RPL and wrote a very slow terminal program on my 48SX!
Regarding the stack: I have found that it really works the same as the four level stack in that if you don't care about an item, you can just forget about it - except that the stack grows instead of discarding the item, so it is up to you to remove things. In programs, new items on the stack are generally consumed by the following instructions. Sometimes you want an item to stay on the stack and you can use DUP and ROT similar to the way you use <Enter> and <Roll(up,down)> on a four level stack machine. There are also ROLL and ROLLD which are generalized to do any number of levels. With the massive number of commands, there must be many cases where one command saves steps - I was very pleased when I found INCR!
I also have a 28S and I did power it up recently to try programming its LCD but I am paranoid about leaving batteries in it since it would be so hard to clean out. Also, even though I have used it very little, one of the plastic heat stakes on my battery door has broken off.
I give a lot of credit to the Forum for giving me ideas to try out on my calculators, that push-started me to do more with them.
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