Re: Ada package registry?

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 07/02/2016 23:16, Georg Bauhaus wrote:
> On 07.02.16 20:57, Dmitry A. Kazakov wrote:
>> On 2016-02-07 20:21, Georg Bauhaus wrote:
>>> Dmitry A. Kazakov <mailbox@dmitry-kazakov.de> wrote:
>>>> On 2016-02-07 10:40, Georg Bauhaus wrote:
>>>>> On 05.02.16 19:47, Dmitry A. Kazakov wrote:
>>>
>>>> Interfaces.X in Ada do not convert anything, it provides Ada types
>>>> exactly matching their alien language counterparts.
>>>
>>> How does Interfaces.X provide matching
>>> types for decimals or task types in C, Cobol, or Fortran?
>>
>> See ARM Annex B.
>
> Let me rephrase: How does the Interface hierarchy from Annex B
> of the Ada LRM provide matching types for decimals or task types in
> C, Cobol, or Fortran? For, if it does not, then the alleged exact
> matches simply are not there. Not even one-way.

The languages like C have few base integral types which Annex B defines. 
Derived types are arrays and records created from the base types with 
pragma Convention applied.

So it boils down to the alien language types algebra mapped onto the 
Ada's types algebra. So far used:

record type operation
array type operation
tagged type operation (for C++ virtual pointer tables)

In short you should be able to describe the data type model in Ada. It 
works well for primitive procedural languages like C. It won't work for 
complicated declarative languages.

> However, there is something in Ada from which to build interfaces for
> SQL RDBMS, for practical reasons.

Ada does not have operations to express RA. As for SQL types the problem 
that they are not the types the DBMS actually uses and not the types at 
the DB client's end.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de