Re: OOP and/or Type Bound Procedure question

[Mikael Morin <mikael dot morin at sfr dot fr>]

On Sunday 20 March 2011 21:01:21 Jerry DeLisle wrote:
> I have started on Derived Type I/O (User Defined).
> 
> I have the attached code now accepted by the compiler, but I am not doing
> any resolution or translation yet.
> 
> Using gdb I am examining the gfc_expr that represents an instance of the
> derived type.  No where do I see how or where the procedure pwf is tied to
> the derived type.  I tried to replace the generic name write(formatted)
> with just a regular name to see what happens not going through the matcher
> changes I made and I still cannot find where the procedure is referenced.
> 
> This being my first venture into this area, I need some hints about where
> to go look for the type bound procedure.  We are going to need to provide
> a pointer to this procedure to the run time library to implement the DTIO.
> 
> TIA,
> 
> Jerry

If you didn't get the info from Janus (or someone else) yet, I can get you 
started from what I know.

The typebound procedures are accessible from the derived_type_symbol-
>f2k_derived->tb_sym_root which is a gfc_symtree mapping names (symtree->name) 
to gfc_typebound_proc structs (symtree->n.tb). Those gfc_typebound_proc 
structs have the union u containing either a gfc_symtree pointer to the 
procedure (symtree->n.sym) directly or a gfc_tbp_generic which is basically a 
linked list of gfc_typebound_proc structs. You can see in 
gfc_match_procedure_in_type and gfc_match_generic how those structs are 
filled. 

For a typebound function gfc_expr (a = b%func()), the relevant field is the 
value union whose subfield compcall contains the needed info in the gfc_expr-
>expr_type==EXPR_COMPCALL case. Especially it contains the gfc_typebound_proc 
retrieved (with gfc_find_typebound_proc) from the derived_type's typebound 
procedures symtree cited above. You can see in gfc_match_varspec how the 
gfc_expr is filled, and in resolve_compcall how the values are used.

For calls (call c%sub()) the gfc_code->expr1 field is a EXPR_COMPCALL gfc_expr 
as described above. 

I hope you find your way.
Mikael