Re: Beginners question: Compound types, how-to?

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

Le Mon, 01 Nov 2010 23:45:36 +0100, Brian Drummond  
<brian_drummond@btconnect.com> a écrit:
> Some people insist on never using "use" clauses, always qualifying  
> names. I can
> see their point but feel that's going a bit too far...
I understand the point. However, to have “package IO renames Ada.Text_IO;”  
and do some “IO.New_Line;” is not a nightmare too. There is also  
subprogram renaming, which allow to move frequently used subprograms to be  
referred to without any prefix. These are two alternatives to Use, not so  
bad. To got further, you may add renaming at the top of a package, and you  
may, as an example, only add renaming for output subprograms. This show  
you what Ada.Text_IO is used for exactly. Tell there is a dependency to a  
package is nice, tell why (and what) is even more succulent.

Some languages which also have packages, like Oberon and Modula-2, has  
another pleasant way : you can selectively import without the need of  
renaming. If you have a unit (the Pascal-heir's name for package) named  
Foo you can import Foo.Bar, Foo.That. I am not sure about the syntax, I  
forget too much, and I do not know if the compiler is required to return  
an error if ever Bar is overloaded in Foo. The difference with Ada, is  
that you do not have to rewrite all the signature. This is a not so bad  
idea, as anyway, when you Use, the signatures are not recalled anywhere  
neither, so this is not more obscure than an import Foo.Bar. This has the  
advantage of being more lightweight, and thus may appeal to use it more  
oftenly.


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