Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!bloom-beacon!apple!claris!hearn
From: hearn@claris.com (Bob Hearn)
Newsgroups: comp.lang.c++
Subject: Re: Are Class Decl.'s Legal in Funcs ?
Message-ID: <9501@claris.com>
Date: 5 Apr 89 17:30:23 GMT
References: <667@oresoft.uu.net>
Organization: Claris Corporation, Mountain View CA
Lines: 31

From article <667@oresoft.uu.net>, by dan@oresoft.uu.net (Daniel Elbaum):
> In article <9418@claris.com> hearn@claris.com (Bob Hearn) writes:
> :From article <890403-150348-4532@Xerox>, by SJohnson.ElSegundo@XEROX.COM:
> :- Is the following code legal ?
> :-
> :- <declaration of function inside class inside function>
> :
> :I don't know about classes nested in functions, but classes nested in
> :classes are legal - except they don't mean what you think they do.  Their
> :scope is global.  This is VERY ANNOYING.  The one thing I hate most about
> :C is lack of nested scoping.
> 
> Declarations nested in class definitions are not global, but are limited
> to the scope enclosing the class definition.  Since class definitions are
> normally performed outside of any block, nested declarations tend to take
> on global scope.
> 
> A declaration of a class in C++ is similar to a declaration of a struture
> in C.  The template may be declared and used in any block, and the scope
> of the template definition is the block within which it is defined.  The
> same is true for any data type.  C certainly has nested scoping.

In a very limited sense.  For C, the most important functionality of nested
scoping is nested functions, which you can't have.  In C++, you also want
nested classes, which you can't have.  These are major deficiencies.
With C++, you can hack around the nested function problem by declaring a
class within your function that has member functions which are effectively
nested functions.  But why should you have to?  

Bob Hearn
hearn@claris.com