Typeof operator in C (Re: An Interesting View of "Strong" Vs. "Weak" Typing)

[3929]

In article <-K016ODxds13 at ficc.uu.net> peter at ficc.uu.net (Peter da Silva) writes:
>> This last sentence bothers me.  It would be quite simple to implement
>> a C operator such as "(typeof) x" that returns some representation of
>> the type of the variable x.
>
>I think this would be a worthwhile innovation, and one that's as easy
>to implement as sizeof. It wouldn't return a value, but would be used
>anywhere a type could be used.
>
>I realise this isn't quite what's meant here. An operator to return
>some indication of the type of an object would be useful, but I'm not
>sure what it'd return. A small integer? A structure? A pointer to a
>structure? The "type" of a C object can be very complex... what would
>it return for:
>
>	struct {
>		union uabc {
>			struct {
>				int a;
>				int b;
>			} ab;
>			long c;
>		} abc;
>		union uabc *d;
>		struct stat buf;
>	} x;
>
>But a typeof operator... wouldn't that be something...
>
>#define SWAP(a,b) {typeof a tmp; tmp=a; a=b; b=tmp}

:-).  Implementing this is, of course, a rather complex task.  Certainly
doable, since this provides at least as much expressive power as operator
overloading in C++.  But by no means is it as easy to implement as sizeof.

>Peter da Silva. +1 713 274 5180. <peter at ficc.uu.net>.

But it sure would be nice...

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