Re: Seeking for papers about tagged types vs access to subprograms

["Yannick Duchêne (Hibou57)" <yannick_duchene@yahoo.fr>]

Le Tue, 14 May 2013 14:16:52 +0200, Dmitry A. Kazakov  
<mailbox@dmitry-kazakov.de> a écrit:

> On Tue, 14 May 2013 13:34:09 +0200, Yannick Duchêne (Hibou57) wrote:
>> An operation has a type,, while a type may be defined without operations
>> (not a lot useful, however still possible).
>
>    procedure Foo;

This is not random data, this has type. The type is implicit in most case  
and becomes more explicit with access to sub‑program (the same with many  
other languages), and as well‑known, there is nothing in Ada looking like  
an access to an untyped entity, which implies the sub‑program has an  
implicit type. You just can't dynamically create or manipulate value of  
that type in Ada (unlike with say, SML or other LISP variant), which makes  
that type special, and prevented it to be given a name, a syntax or ever  
be explicitly referred to in Ada (not the same with all languages).

>> If a program is mainly a structure, then it is mainly made of typed  
>> values
>> (and the program as a whole, is a complex value).
>
> No idea, what does this mean.
>
> Value is not a programming language term, it belongs to the application
> domain.

Then think about meta‑programming or “programming as a human activity”.  
That said, obviously, the concept of value I referred to, was either at a  
level higher than values manipulated by the program, or else, constants  
values referred to (and interpreted) by the program.


-- 
“Syntactic sugar causes cancer of the semi-colons.” [1]
“Structured Programming supports the law of the excluded muddle.” [1]
[1]: Epigrams on Programming — Alan J. — P. Yale University