Re: [boost] Re: Re: Yet another Variant class

From: Joel de Guzman (djowel_at_[hidden])
Date: 2002-07-01 21:48:42

Douglas Gregor wrote:

>
>
>PyObject*, variant, any -- they're all just union types. Is a union a 
>container of one?
>	
>
Very interesting discussion....

My intuition favors the first view: that variant (union, any, PyObject*) 
*is a*
superclass (superset, union) of all its possible types. It makes perfect 
sense.
The word "union" says it all.

However, I don't see why "extract" can't be used instead of "cast".
If you think of the variant (or union) as a *union* in terms of sets, then
"extract" seems analogous to *extracting* a subset. This view seems
perfectly logical to me. On the other hand, a cast, in my mind connotes a
conversion from a type to another type which might even involve a conversion
from a totally unrelated type.

2c worth....
--Joel