Plus42 Equations, Preview Release

[Thomas Okken]

New update: mostly bug fixes

WARNING!!!

For reasons I'll go into below, this new build will not handle older state files. If you have a state file with anything useful in it, be sure to export your programs and data first. In particular, you can save your equation list by copying the EQNS list on the HP-42S side, or by doing Copy in the list view on the Equations side.

Why the incompatible change?

Plus42 has a new data type, the equation object, that is a bit tricky to handle under the hood. On the one hand, it is a data object, using shared data, much like the matrix and list types. But on the other hand, it is also a code object, containing executable code, generated from the parsed expressions.

This mixing of data and code within one object type creates headaches because of the way state file persistence is handled in the Free42 code. I thought I had implemented a pretty elegant solution for this, but I could never really get the bugs out, as Vincent can attest. In the end, I decided to give up on it, and changed to a completely different approach.

The new approach is far simpler than the old one, and should be more robust. Unfortunately, I can't promise I didn't introduce any new bugs with this change, since it was rather drastic. But at least I should be able to actually troubleshoot this new logic, so it will eventually become as solid as Free42 again. I apologize for the upheaval, and thank everyone testing this for their patience!

The only other new thing is that this version finally treats ^ and ↑ as distinct characters.
And it fixes the bug with named equations.