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From: Valentin Bonnard <Bonnard.V@wanadoo.fr>
Subject: Re: nested functions
Date: 1999/06/06
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Approved: Valentin Bonnard <bonnard@clipper.ens.fr>
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gbush@my-deja.com wrote:

> C++ unlike other languages doesn't support nested functions. I
> understand, bad heredity. But C++ had an opportunity to escape from
> this predicament by allowing classes inside function body see the local
> non-static variables, defined in the outer scope as well as function
> parameters. For some reason it was not done. I wonder, is there at
> least one good reason why it is so? (You see, I don't ask about five
> good reasons anymore, just one.) I understand, certainly, that someone
> could return object that contains references to local variables, but it
> hardly can be considered a good reason.

This has already been discussed here.

Andrew Koenig said (approximatly) that it was a big 
philosophical change to allow local classes to 
access locals.

James and I propose to introduce a new class, 
__local_context, defined in every function 
scope, which represents the locals in the scope.

Then all you would need to do is to derive your 
local class from this class:

void foo ()
{
    int i;

    struct loc : __local_context {
        int operator() () { return i; }
        loc (__local_context c) : __local_context (c) {}
    };
    cout << loc (__local_context());
}

...well, you get the idea; if you add a lambda 
construct for creating local clases easilly, and 
give local classes external linkage, then you 
get a functionnal language.

-- 

Valentin Bonnard
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