Little explorations with HP calculators (no Prime)

[3298]

(03-20-2018 11:59 PM)brickviking Wrote:  The Casio 9750/9860-based family have Lists, which are basically single-dimension arrays of numbers, up to 999 per list (or 255 for older versions). They also have Files, which have 6 Lists (9750g+) or 26 Lists (9750gII/9860gII).

I wanna throw in a few more numbers: AFX has 20 lists per file (and if I recall correctly, it allows 999 items per list), and there are 6 files on every Casio I've seen. The 9860 series also adds a list label (basically a string) as List n[0], but I can't remember if that existed before OS 2.0 or only after.

(03-20-2018 11:59 PM)brickviking Wrote:  Here's how I use them to emulate the behaviour of "local" variables.

I stash a complete copy of the global variables A-Z, Theta and r, into a List. I generally use the last List on the calculator in the last File so it's less likely to get in the way of already-created Lists. I can then use the variables any way I like, because I then restore the copy I stashed aside when I've finished. I never bothered using Matrix functions, as I find the existing List behaviour works for me, at least for now.

Plenty of people do that, but it breaks down when the program you're calling does the same on exactly that list (and the last list in file 6 is quite commonly used for that purpose), because the list cannot really be operated as a stack, so the called program will overwrite the caller's saved variables.
That may be one of the reasons for the absence of a (math, science, whatever) library ecosystem like the ones we have for the various calculators from HP. There are plenty of interactive math / science programs, but you can't use them as subroutines that way.

(03-20-2018 11:59 PM)brickviking Wrote:  Hm, when did this particular conversation get derailed from HP explorations? :/

... I think that happened when pier4r started comparing HPs to Casios and TIs; the helpful Casio and TI calculator owners in this forum jumped in and provided him with information to satisfy his curiosity. But let's get back on track, shall we?