Re: Standard Queue status

["Marin David Condic" <dont.bother.mcondic.auntie.spam@[acm.org>]

What about this:

package Unbounded_Arrays is
    type Array_Type is private ; --etc...
end Unbounded_Arrays ;

package Unbounded_Lists is
    type List_Type is private ; -- etc...
end Unbounded_Lists ;

with Unbounded_Arrays ;
package Unbounded_Lists.Lesser_Used_Operations is
    function To_Unbounded_List (
        Item : in Unbounded_Arrays.Array_Type) return List_Type ;
end Unbounded_Lists.Less_Used_Operations ;

This has a variety of advantages. The package Unbounded_Lists supplies just
the basic plain-vanilla operations one needs for a list, so it isn't a
burden for the simple cases. There might be a whole variety of other similar
conversions one might want to perform - such as changing Maps into Lists or
Trees into Lists - we don't yet know what all of the possible abstract types
are that we might want to build or what sort of conversions would be
desirable. We are also likely to discover a large variety of
lesser-used-yet-still-useful operations that we might want to bundle up
somehwere and have available - a child package seems like the proper place
for all this potential baggage.

Want a simple list? Use Unbounded_Lists. Want to perform conversions between
all of our standard components? Grab Unbounded_Lists.Conversions and go
through a few complicated gyrations to get it to work. Want to compute
statistics on your list data? Bring in Unbounded_Lists.Statistics. Want some
clever-but-obscure list operations? Bring in Unbounded_Lists.Tenebrous.
Defering to child packages lets us initially concentrate on the really
fundamental stuff first & leave the rest for later.

I have not given much thought as to how to deal with the instantiations - it
does look like a kind of double-inheritance. However, we could probably come
up with something that stalled the operations off to a child package.
(Unbounded arrays become a descendent of unbounded lists? Gen-Spec
relationship?)

MDC

--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Ted Dennison" <dennison@telepath.com> wrote in message
news:IPrN7.42250$xS6.70888@www.newsranger.com...
>
> The issue is wheather to provide for converting between them and lists.
Note
> that Ada.Strings.Unbounded does this exact same thing for Strings and
> Unbounded_String's. The only real difference is that the String type
already
> exists, whereas the unbounded array type would have to be declared in the
> package.
>