RPN83P: RPN calculator for TI-83+ TI-84+ inspired by HP-42S

[jthole]

(12-04-2023 04:10 AM)bxparks Wrote:  Off the top of my head, I can think of some major obstacles or features that need to be addressed:

* A program/file browser: The user needs to be able to view, select, and execute the BASIC program from the RPN83P program. No idea how easy or hard this would be.
* Handling archived programs: A BASIC program can be "archived" into flash memory. Normally, TI-OS forces you to "unarchive" the program to RAM before it can be executed. There are "shells" that have gotten around that and allow launching programs from flash directly, but that level of TI-OS manipulation is beyond my technical expertise.

First of all, I have no experience with TI-Basic, so maybe it's a horrible language (I saw that Forth and BBC Basic interpreters are available as community projects as well).
Before trying a TI-84 Plus for testing your excellent RPN app, I had no TI experience at all.

But the way I was thinking (and maybe that's very difficult or impractical to do):

- in the TI-84 Plus "shell", you can execute a Basic program, by executing the 'prgm' command, concatenated by the program name (it would have been nicer if you could specify the program name as an argument of a prgm() command).
- I think it's reasonable condition to expect that a program should be in RAM (so no dealing with archived programs), and that the user knows the TI-Basic program name and is able to type it in.
- maybe from within the RPN app, you could request the program name, hand control to the native TI shell, and have it execute the prgm<Program name> command.
- ideally execution should jump back to the RPN app after completion of the TI-Basic program, but it would be acceptable to call it up from the Apps menu as well.
- if you want to re-use values generated by the TI-Basic program, you should put those in the REGS variable (or make sure the value is available in the Ans "variable?").
- the other way around, inputs for the TI-Basic program should also be in a register (or in the L on the RPN stack).

I am not sure if this would be doable, and would be really worth it. Of course, you can already exit the RPN app, execute a program from the TI-shell, and return to the RPN app. Your choice of using a REGS variable ensures that you already can use that from within a TI-Basic program (theory from my side, I have not tested that yet).

While keystroke programming would be superior, in my opinion, I think having the RPN app as a non-programmable scientific calculator, and using the native TI-84 Plus functionality for the remaining functions (programming, solver) might be a pragrmatic solution.