Re: Clause "with and use"

[Gautier Write-only <gautier@fakeaddress.nil>]

Robert I. Eachus:

> Bzzzt! Wrong Answer, try again.  A use clasue in Ada does NOT imply that
> there is a with around somewhere.  Try compiling:
> 
> procedure Junk is
>    use Ascii;
> begin null; end Junk;
> 
> If you have any doubts about that.
> 
> Ascii is somewhat special, but fairly common is:
> 
> package Outer is...
>     package Inner is...
> 
> end Outer;
> 
> package body Outer is
>    use Inner;
>    ...
> end Outer;
> 
> Again a use clause without a with clause in sight.

Both "use" you cite are not context clauses -> OT, sorry !

BTW, your mention of ASCII is interesting.
* Ada 83 (and later) implies a non-written "with Standard; use Standard;"
  - ASCII is subpackage of Standard.
* Ada 95 (and later) implies a non-written "with Ada, Ada.Strings;" when you
  just write "with Ada.Strings.Maps;". Same for all children 

-> things are not at all 100% explicit in the present standard.

* The "[with and ]use" proposal offers the possibility of writing once
  the name of a package instead of twice when you use "use" in a context clause.

-> this feature doesn't reduce from 1 to 0 the appearance of a package name
   like both mentioned above, but from 2 to 1. When the feature is used, the
   names remain explicit, but without redundance.

Clearly the contestation about this proposal is just because this is an evolution.
Existing elements are by default sacred, improvements are by default suscpicious...
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Gautier  --  http://www.mysunrise.ch/users/gdm/gsoft.htm

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