Re: [boost] Variant (aka Discriminated Union) implementation

From: Ruslan Zasukhin (sunshine_at_[hidden])
Date: 2002-06-25 08:50:11

on 6/25/02 16:32, Douglas Gregor at gregod_at_[hidden] wrote:

> On Tuesday 25 June 2002 02:19 am, Ruslan Zasukhin wrote:
>>> I'm glad to see work on a variant type. It's been discussed a million
>>> times, but we've never had a variant type come up for review (and I've
>>> needed one for a LONG time).
>> 
>> I have work on similar task in Valentina database not so far.
>> But I have made code using Interface way.
>> 
>> So I wonder (note, I am new to boost)
>> 
>>     Why boost org always try go by template way only ?
>>     Why I do not see solutions based on interfaces ?
> 
> You do see solutions based on interfaces, but the interfaces are resolved at
> compile time using templates instead of at run-time using virtual functions.
> With a variant type, for instance, this allows complete type checking to
> occur at compile-time instead of pushing all checking to run-time.

Okay, but template-based solution is LIMITED for use on compile-time.

In database application or script languages, for example,
variant values are created at run-time,
So as far as I see, templates not work here. Agree?

This is why for such applications we need

Class IValue {}
Class IntValue : public IValue {}
Class FloatValue : public IValue {}
Class StringValue : public IValue {}

And so on.

Does BOOST org interested in such solutions?

-- 
Best regards,
Ruslan Zasukhin              [ I feel the need...the need for speed ]
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