Re: [boost] Getting the contained object from boost::function

From: David Abrahams (david.abrahams_at_[hidden])
Date: 2001-10-10 10:37:01

----- Original Message -----
From: "Peter Dimov" <pdimov_at_[hidden]>
>
> Perhaps it's time to discuss a common 'variant-to-contained-object' cast
> that would work on any, function, and the future discriminated union and
> "bounded" variant.
>
> The easiest approach is to just adopt the name 'any_cast' but I don't like
> it much. any_derived words are usually misleading. Any cast?
>
> A problem with the precise definition of such a cast is when is the
returned
> pointer/reference invalidated.

Interesting naming problem. This "cast" has a few interesting properties:

1. The source supplies almost NO type information describing what types may
be "cast-to".
2. The result object is in some sense "contained" in the source.
Any others?

I'm not sure how relevant (2) is, but the combination of 1&2 leads me to
like "extract<T>(source)".

-Dave