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From: "Martin Dowie" <martin.dowie@btopenworld.com>
Newsgroups: comp.lang.ada
Subject: Re: Conditional compilation in Ada?
Date: Thu, 18 Nov 2004 06:49:07 +0000 (UTC)
Organization: BT Openworld
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Date: 2004-11-18T06:49:07+00:00
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"Steve" <nospam_steved94@comcast.net> wrote in message 
news:CfVmd.110500$R05.57670@attbi_s53...
> Using variant records means explicitly checking for the variant type and
> taking different action based on the variant.  Creating a new variation of
> the record means modifying the original record (modifying proven code is
> never a good thing when it is easily avoided) and chasing each part of the
> code that takes different action based on the variants.

But the compiler will help you, so long as you use a 'case' with no 'others' 
branch. And the check on the variant can be done at compile time not 
run-time if it is known and assigned to a constant.

> Using objects means deriving a new object and overloading specific
> operations for that object.  The base object isn't touched.
>
> Also: If the object is declared statically, the dispatching may happen
> statically.

I've seen compilers that do this for the variant record method (most seem to 
in my experience) - is this true for the OO method?

Cheers

-- Martin