This program basically should be used with OnBlock and Start-Up. I still need a way to prevent syntax errors, however. If anybody can come up with some code to prevent syntax errors from occuring, please add it in! Basically, this program screws up calculations by adding/subtracting 0 through 3 from the answer. Of course, there *is* an "exit phrase" to escape the program. It's literally a smiley face. If you simply type : then ) and press ENTER at the prompt, it will quit. Anyway, I really *do* need code to prevent syntax errors or it just doesn't work correctly (it is easy to exit until I get some code to keep syntax errors from occurring ). So please, help me with this project!

http://sc.cemetech.net/?xpi=d96ff8d421bc1c56916185250a731337

Some suggestions:

1) it's faster and easier to use expr(String) instead of doing the Y1 trick
2) You can save space by using 2/3 and 1/3 instead of 0.66666 and 0.33333, and you lose immeasurably little speed.
3) I'm afraid there's really no way to not get syntax errors other than manually parsing the string, which is doable for four-function calculations but laughably challenging for anything more complex.

There is an ASM error-trapper floating around somewhere that I one of the DetachedSolutions forum members cooked up when I was working on a TI-Basic CLI.

And you showed that to me months or years ago, and I think I even used it for something. I went to try to find that particular topic, only to discover that in its abandonment the Detached Solutions forum seems to have become a haven for malware.