🚀 go-pugleaf

In article <311@csun1.UUCP>, weyrich@csun1.UUCP (Orville Weyrich) writes:
> I think that this discussion points out a neglected aspect of programming
> language development and language standardization: defining standard and
> useful interfaces *between* languages, so that for example new code in modern
> languages can be smoothly integrated into old programs written in old languages
> without the need for massive rewrites. 
> 
> DEC demonstrates that this can be done in the VAX/VMS family of programming
> languages (although this is a private DEC standard).
> 
> Of course, such a proposal is not expected to be greeted with a warm welcome
> by certain mainframe manufactures who have trouble getting their own standard
> linkage conventions standardized :-), or those who have separate and
> incompatible runtime libraries for each language :-), or those who do not
> have language-independent code generators :-).
> 
On the basis of conversations I've had with the language development folks
from MY vendor, they'd like nothing better than to be able to do just that.
But there are lots of issues, some of them pretty nasty.  First, to take
an existing environment in which all the languages work differently
and move to a common library environment, somebody's got to change. Thats
a nasty word around people with lots of "dusty decks" that they don't wnat
to have break because sombody changed the way the library works in some
subtle way.  My understanding is that by starting more or less from scratch,
DEC didn't have to worry about this so much with the VAX family.  Secondly,
there's the issue of "who's the boss here" when you have multiple 
languages involved - if a run-time error occurs, who takes care of it, and
how?  What happens when the standard or customary action is different
between the two languages (E.G. fixed-point overflow in Fortran vs PLI).
Again, a truly common linkage/library system might be able to address this
by knowing exactly what sort of routine was in control at the time of the
error, but that could get pretty messy, and expensive.  Finally, in
defining a common linkage convention, you have to allow for all the bells
and whistles every language needs, or you have to be able to tell at 
compile time what sort of module you are linking to.  This is likely to
have nasty effects on linkage overhead from the standpoint of FORTRAN and
C folks who are accustomed to quick, simple, and computationally cheap
linkages.  (This problem is not strictly a inter-language problem -
making F77 and F8x get along will entail similar headaches). 
Now if we can just get around all that (and the stuff I have no doubt
forgotten) we'll be cruisin'.  I agree that if the environment worked
well, a lot of the "multiple license" arguments would probably go away,
and we'd also probably have a lot more professionals proficient in 
multiple languages.  
 
     Scott Denham 
      Western Atlas International
       Houston, TX
> 
> What does the rest of the net think?
> 
> -- 
> Orville R. Weyrich, Jr.          | UUCP    : ...gatech!ugacs!csun1!weyrich