Re: Fun with WebAda/GNAT

[dewar@cs.nyu.edu (Robert Dewar)]

Ken explained about the lack of delete function in Web Ada causing trouble ...

Ah, yes, I see what you mean! Yes, indeed the delete is fundamental in
a case like this. Note that it can also arise if you do the following
steps:

a) compile a package spec called x.ads that does not need a body

b) compile subsequently a procedure body called x.adb that either needs
no spec or a corresponding procedure spec.

The RM specifically says that the procedure body overrides the spec in
this case, but GNAT insists that the dubious file be removed. Note that
if you have no delete, then there is no solution AT ALL to the problem
I outline above other than supplying a dummy procedure spec.

Worse still, the new 3.07 version of GNAT has a new check that there is
no junk body file around. Now imagine:

a) compile a procedure body x.adb

b) compile a generic instantiation x.ads

GNAT will now insist that you removed the junk x.adb file before proceeding,
and if you have no delete file, then you are *really* stuck, since there
is no corresponding dummy body that can be supplied.

So I agree, a delete file functionality is fundamental to the source
based model that GNAT uses, since in some cases removing things from the
environment requires the deletion of the correspoinding source files.

Note: the ACVC requires that these deletions occcur automatically, so for
the ACVC, we use a special script that actually deletes the junk files
silently, but it is hard to believe that anyone would want this to be a
normal mode of operation.