I'm currently writing a maximally ANSI-compliant Forth shell for the TI-83. Features will include breakpoints, dictionary editor, and memory monitor. I'll keep you updated.

Sounds cool. Will this be for the regular TI-83, or the TI 83+ series?

Both, I suppose. What compatibility issues are there between the two?

The TI-83 doesn't have Flash or B_CALLs.

In that case, it'll be for the 83+ family. I may port to more platforms in the future depending on its success. I can see Forth having very practical application on a TI calc given it has a sufficiently simple interface and sufficiently large std dictionary.

Can you explain what a Forth shell is for the members here that have particularly poor JFGI skills?

http://en.wikipedia.org/wiki/Forth_%28programming_language%29

Sure. Wikipedia says it best, but in short, Forth is a stack-oriented high-level programming language. A Forth shell is a kind of interface for interactively developing, debugging, and running Forth programs. If you've ever used the interactive shell for Lua, for example, you're probably already familiar with this type of application.

One more possible feature: compiling to threaded code. Compared to hand-coded assembly, it's slower, but simpler and equally powerful. Compared to TI-BASIC, it's faster and more powerful, but arguably more difficult. Also, Forth programs are notorious for being hard to maintain. It might be a worthwhile trade-off. If nothing else, it'll be fun to play around with.

Edit: I wouldn't say z80 asm programs are exceptionally easy to maintain either.

I'd go pretty far in the other direction and say that z80 ASM programs are exceptionally difficult to maintain. Thanks for the excellent summary; Elfprince, I had of course taken a look at that. Some of us are worse at JFGIing than others, in my opinion. And Progbeard, I definitely hope you're able to make some progress on this, it seems significantly more novel than many of the third-party calculator OS concepts that I've seen.

I was just providing what should be the first step for the JFGI impaired

Well this is actually going to be a program, maybe an app. I've hit a few roadblocks. If I follow ANS FORTH standards, it will be a deal more complex than it really needs to be, so I'm abandoning that and a lot of the dictionary complexities in order to salvage speed. That also means abandoning a lot of unnecessary predefined words. The standard output will be the homescreen, but I'll eventually support graphical output. The Z80 won't really like threaded code and it certainly won't like interpreted threaded code, so you might have to watch out for how deep your word references go when you're building your dictionary. But it will all be functional.

Too slow. I may take this project back up later.

What's too slow, your prototype? Is there anything we can do to help you perhaps make it faster?