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Date: Mon, 17 May 2004 13:40:02 -0400
From: Hyman Rosen <hyrosen@mail.com>
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Subject: Re: "Must instantiate controlled types at library level." Why?
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Date: 2004-05-17T13:40:02-04:00
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Georg Bauhaus wrote:
> Is an approach based on discipline and
> conventinalism on a par with language definitions?

Shrug. How many students of Ada have fallen down trying to
create an array of ragged strings?

> Somewhat related to this, you can have template parameter constraints
> But is it the same as saying
>    generic type G is new C with private;

Not really, but especially in C++, there are philosophical
arguments against constraining template parameters in this
way. Because of the many possible ways in which a construct
might work (because of automatic conversions, etc.), and
because uninstantiated template functions don't need to be
correct for types with which they are not used, it's better
to let the compiler complain on inapprpriate instantiations
instead of trying to capture a priori constraints.