Re: How is U2 different from XyWrite?

[J R FOX jr_fox@xxxxxxxxxx]

--- "John H. Kessel"  wrote:

> interaction
> between XyW and
> VDM, the OS, and any other applications involved.
> Does U2 "translate" the
> XyW output
> so it can be understood by the "external programs?"
> "Translate" commands
> from the
> "external" programs so XyW can respond to them? Or
> is its fundamental task
> something
> different?

Let me take a quick, probably clumsy pass at this.
Programs are either compiled (into executables), or
interpreted at runtime by an interpreter. XPL is an
example of the latter, I believe, with XyWrite
functioning as the interpreter in this case. A number
of applications -- such as database or spreadsheet
apps -- have included a programming language of some
kind. WORD has some variant of Visual Basic, so it's
not unheard of for Word Processors, either. Xy
programs -- whether short keyboard macros or elaborate
XPL frames -- are run by Xy and you get output that
amounts to helpful automation, as if you were
*quickly* doing a lot of things not easily done from
scratch by the user without benefit of the routine;
alternately, as with the U2 library, you have a lot of
*new, user added* features and functionality not
(directly) envisioned by the creators of Xy, but made
possible by means of the programming language. (This
might be compared to all the many user-created
"extensions" that are floating around for Mozilla /
FireFox / SeaMonkey ?) Xy itself is written in
Assembler, which is a computer language much closer to
the base machine code than "higher order" languages
like C++. But the end result is an extensive series
of instructions that does things to or on the hardware
-- particularly the screen -- and the file (in our
case, document) in memory, which gets our work done.

I'm not sure if that addressed your question, or how
badly I may have screwed up the answer.


Jordan