Time for another progress report!
I added variables today - actually, they're really just named constants, as the program can't perform symbolic manipulations on them. (Though I wonder how hard that would be given what I've set up so far...
) I added 3 built-in variables: pi, e, and c (the speed of light). Any more you might want?
I also added the "E" operator, which does scientific notation, e.g. 3E6 means 3 million.
All that's left now is those pesky functions (and those aren't really even crucial, as long as I can do the single-parameter ones as unary operators) and then I can start incorporating the SE4 files into a client program for this app!
