Procedural Types

Procedural Types

[Umut DURAK]

Is it possible to define procedural types in ADA95 ? CLearly is it
possible to define procedure type and implement various procedures
with the same type ?

Re: Procedural Types

[christoph.grein]

> Is it possible to define procedural types in ADA95 ? CLearly is it
> possible to define procedure type and implement various procedures
> with the same type ?

Strictly speaking, there are no subprogram types (procedure and function types).

Less strictly speaking, a subprogram type is defined by its parameter and return 
profile. So any subprogram matching the profile can e.g. be used as an actual 
parameter in a generic instantiation.

There are also subprogram access types (pointers). Any subprogram matching the 
pointer profile can be assigned to such a pointer (if the access level is 
correct).

type P_Pointer is access procedure;

procedure Proc;

P: P_Pointer := Proc'Access;

P.all;  -- call Proc

type F_Pointer is access function (X: A_Type) return Another_Type;

function Func (X: A_Type) return Another_Type;

F: F_Pointer := Func'Access;

V := F.all (X);  -- call Func
V := F (X);      -- call Func (implecit dereference)

Re: Procedural Types

[Dmitry A. Kazakov]

On 14 Oct 2003 23:59:00 -0700, durakumut@hotmail.com (Umut DURAK)
wrote:

>Is it possible to define procedural types in ADA95 ? CLearly is it
>possible to define procedure type and implement various procedures
>with the same type ?

Unfortunately, no. There are only:

1. pointers to subroutines

2. formal subroutine parameters of generic packages

Thus if you want to pass a subroutine as a parameter you almost always
have to break accessibility checks per brute force, or alternatively
you have to make things generic. Keep also in mind that to pass a
dispatching subroutine is not a trivial task.

---
Regards,
Dmitry Kazakov
www.dmitry-kazakov.de