Plus42 Equations, Preview Release

[Thomas Okken]

New update. Only changes under the hood this time:

The way EDITN and INDEX kept track of which matrix they were working on needed revisiting. Merely keeping track of the name is no longer enough when you have directories. So, now it keeps track of the matrix name *and* the directory where it resides, or, for local variables, the stack level.

With this information, it is no longer necessary to deal with the situation where LSTO creates a variable that hides the currently edited/indexed matrix. EDITN and INDEX can still find it, even if it is hidden. And they can now also find it, even if the user used CHDIR while editing.

The logic for saving IJ on the stack when a local matrix is edited or indexed is still there; that's not meant to deal with the edited matrix being hidden, but to deal with a subroutine being able to edit a local matrix without interfering with INDEX state in the caller.

To make a long story short: lots of changes, but you shouldn't notice anything, other than that changing directories will no longer confuse EDITN and INDEX, and they will happily keep working, even if the matrix they are working on has been hidden by LSTO.

Apart from whatever bugs still need to be fixed, this should be the last update before work starts on the big display...