On Wed, Jun 13, 2018 at 1:48 PM, James H. H. Lampert
<jamesl@xxxxxxxxxxxxxxxxx> wrote:
On 6/13/18, 10:35 AM, Jack Woehr wrote:
Yeah, I was going to say ... you have it already ... it's called "ILE C"
:)
Except that C is not what I would call a true HLL. At least, not in the
sense of BASIC, FORTRAN, RPG, COBOL, PL/I, Pascal, or Java (even though Java
syntax is based on C syntax). More a mid-level language: higher level than
assembler, lower than a true HLL, and more than enough rope to hang
yourself.
This raises an interesting question. When we label a language by its
abstraction level, are we talking about how abstract the language
*allows* us to be? Or how abstract programs in that language
*typically* are? Or how strongly we are *prevented* from accessing
lower-level features? Or something else?
Most people categorize C in roughly the same level as Fortran (note
it's not spelled in all caps anymore). Both are pretty low by modern
standards, but significantly higher than assembly. Of the group you
listed, C is special because it gives the most unfettered access to
lower-level features, and it's the only one of those to be widely used
to write compilers and operating systems. But you can easily use C
exactly as you would use Basic (also no longer all caps) or Pascal,
and indeed that's exactly how I used C when I was programming in it.
Actually, you could easily argue that C is higher level than several
early incarnations of BASIC (all caps to emphasize the earliness),
which didn't even have proper procedures or functions. (There was
GOSUB, kind of like RPG's EXSR.) Similarly, FORTRAN didn't allow
recursion, though nowadays Fortran does.
Java also stands out among those you listed, because it's quite
clearly higher level than any of the others.
I still wish PL/I had taken off. Now there's a language where you can almost
say, "You know what I want; just do it." If it had taken off, then we'd
probably have Object PL/I (it exists, but only just barely) instead of C++,
Objective C, and Java.
Even in the most optimistic scenario, PL/I would never have supplanted
C. Thus at minimum there would still be C++. And from there it is hard
to imagine that the slew of other C-descended languages wouldn't have
also arisen.
I do think it would have been nice for PL/I to have become more
popular than it has. I definitely agree it would make a very nice ILE
option. But compatibility with existing code matters a lot, so there
was never any chance RPG would have gone away, and it's vastly easier
to improve RPG than to maintain and develop both RPG and PL/I.
John Y.
midrange.com
