(j3.2006) About extending abstract types with deferred bindings

[Lionel, Steve]

F08/0052 (see http://j3-fortran.org/doc/year/11/11-207r1.txt for final
wording) discusses an abstract type with a private, deferred type-bound
procedure and asks about extending that type in another module that makes
the type accessible by use association. The interp's edit adds the words "an
accessible" to:

 

If a specific type-bound procedure specified in a type definition has the
same binding name as an accessible

3 type-bound procedure from the parent type then the binding specified in
the type definition overrides the one

4 from the parent type.

 

I can follow that. However, the text and answer to Q3 say, respectively,
".the

definition of type t2 would seem to be defective in that (7) must be

defining a new type-bound procedure, and not overriding the type-bound

procedure defined at (6), and that therefore t2 still has a deferred

type-bound procedure.  That would mean that an abstract type with a

private deferred type-bound procedure could not be extended outside of

the module in which it is defined: is that correct?" and

 

"Yes, an abstract type with a private deferred type-bound procedure

    cannot be extended outside the defining module, because it is

    otherwise impossible to override the private type-bound procedure."

 

This clearly suggests that there is a rule specifying that all deferred
bindings in an abstract type must be overridden when extended, but I can't
find it and I have tried many ways to search in F2003, 2008 and 16-007r2.
Yet it must be there somewhere as the interp references it and Intel Fortran
insists it be followed. What have I missed?

 

This comes up because a couple of our customers bemoaned the restriction in
F08/0052, saying "The result of the interp results in a capability gap for
authors when they want a binding that can be overriden but not invoked", and
asked that such a capability be provided in a future standard.

 

Steve Lionel

Intel Developer Support

Merrimack, NH

 

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