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From: "Martin Dowie" <martin.dowie@nospam.baesystems.com>
Newsgroups: comp.lang.ada
References: <3BECA3B7.5020702@telepath.com> <3bef920f@pull.gecm.com>
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Subject: Re: List container strawman 1.2
Date: Mon, 12 Nov 2001 16:58:54 -0000
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"Marin David Condic" <dont.bother.mcondic.auntie.spam@[acm.org> wrote in
message news:9soq34$be6$1@nh.pace.co.uk...
> Lots of ways of handling that. I agree that there are cases where you want
a
> list to contain only one sample of a given element, but I'd prefer that
the
> instantiation doesn't force someone to make that decision and have to
> provide parameters that may be unnecessary for the simple cases. It could
> just as easily be done by providing a subprogram to set a flag in the List
> object that disallows/allows duplicates. Or alternately, returning a flag
on
> insertion indicating there was a duplicate or providing a function to test
> for a duplicate, or .... ? IOW, default behavior is "duplicates allowed"
> unless you call "Disallow_Duplicates (My_List_Object) ;" or something
> similar.

Well, the biggest benefit we found with this method was that it allowed
the compiler to optimise away various paths on instantiation depending on
the
parameter passed. You could always have:

    Elements_Must_Be_Unique : Boolean := False;

The actual code difference between the two variants is very small and would
save having two package sources to maintain, which would have (almost)
exactly
the same specification.