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From: ags@seaman.cc.purdue.edu (Dave Seaman)
Newsgroups: comp.lang.fortran
Subject: Re: What is the FORTRAN for ?
Message-ID: <13293@mentor.cc.purdue.edu>
Date: 24 Aug 90 15:36:10 GMT
References: <13071@mentor.cc.purdue.edu> <60978@lanl.gov>
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Reply-To: ags@seaman.cc.purdue.edu (Dave Seaman)
Organization: Purdue University
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In article <60978@lanl.gov> jlg@lanl.gov (Jim Giles) writes:
>From article <13071@mentor.cc.purdue.edu>, by ags@seaman.cc.purdue.edu (Dave Seaman):
>> [...]
>> The two examples I gave of incompatible Fortrans ...
>> were fundamentally incompatible at the object code
>> level.  They are definitely not callable from each other.  
>
>I'll bet they _were_ callable from each other - it may have taken a
>substantial bridge, but it could be done.  There is obviously no HLL
>visible incompatibility between the _standard_ parts of the two
>languages (the only parts that you can legitimately expect to be
>call compatible anyway).

If, by "a substantial bridge", you mean an a special intelligent version of 
the linking loader that would:

	1.  cause all subroutine/function calls to be routed through a bridge
	    routine that would examine the argument lists and transform them,
	    when necessary, into the form expected by the called routine, and

	2.  transform all I/O requests to the nonresident I/O system (the one
	    not initialized by the main program) into the equivalent call in
	    the other system (which would probably require an extensive table
	    of routines to watch for, and specially-written library routines to
	    do the equivalent in the other I/O system, since there is no 1-1
	    correspondence between the two), and

	3.  resolve name conflicts at load time caused by different routines
	    being loaded from different libraries with the same name but
	    different functions,

then I suppose you are right in saying that it could be done.  What would be
your reaction if a vendor sold you a product with the claim that something
"could be done", and you later found out that doing it would require several
man-years of reprogramming?

--
Dave Seaman	  					
ags@seaman.cc.purdue.edu