[fpc-pascal] fpc-passrc expression parser (issue #16914)

[dmitry boyarintsev]

Hello, Michael Van Canneyt,

Sorry, I can't write to the resolved issue (without re-opening) it.

> - better class tree (split out binary/unary/primitive operators in subclasses)
> These may break backwards compatiblity; if you prefer to do them yourself, I can say what I have in mind.

That's how it was originally written. However, I personally prefer to
keep less subclasses.
I would like to hear your ideas.

thanks,
dmitry

P.S.. the expression parser still doesn't resolve ranges (i.e. in
sets), neither simple nor complex, like:

Char(6) in [Char(sizeof(Integer))..Char(SizeOf(int64))]