I don’t recall what brought this up, but while poking about BASIC I came across a reference that I think you might all find useful:
The BASIC Handbook : encyclopedia of the basic computer language
Although its historical notes are mostly wrong (most of the things it attributes to this or that BASIC are originally from Dartmouth) it has a pretty good overall comparison of the various dialects. The notes at the end on Atom BASIC were definitely useful.
Scruss: note the SEG$ here, which is like MID. Looks like there was no real way to know which one you’d end up with except on a platform by platform basis.
(For specifics on the Atom and its Basic, see Atomic Theory and Practice)
I purchased this book back in 1980, when I was in high school. It was very useful because I had access to both Commodore PET and TRS-80 Model I systems and it was nice to have 1 reference book that covered both.
The “historical” notes really aren’t meant to be historical. Since the book is supposed to cover BASIC on many different platforms (mostly microcomputer systems), the notes are just to denote system-specific variations of BASIC. Ex “MID” on the Harris vs. “MID$” on most other systems, or “RESET” as a TRS-80-specific command.