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From: Steven Watanabe (steven_at_[hidden])
Date: 2006-12-14 15:59:58


Weapon Liu wrote:
> I think this is the right place to ask this question.
> As cool as boost::fusion is, there's still one question that bothers me,
> that is, if boost::fusion is the hammer, then what's the nail?
> I sure know that it's generic( more so than boost::tuple) and it's
> complete( with a bundle of algorithms and cool utilities), and it seems
> that it "solves" some problem quite well( when I read the documents).
> However, I found it bothering that the documents didn't even mention one
> real-world application( boost libs aside).
> Based on my experience, the most frequent scenarios where
> boost::tuple/fusion is useful are those where one needs a
> generated-on-the-fly struct for holding return values bundle, or where
> one needs to return multiple values transparently( well, nearly so),
> just like those lua does.
> Other than that, I can't really imagine a scenario where this kinda
> stuff kicks butts. The biggest disadvantage of boost::fusion, I think,
> is that the size of it is known and fixed at compile time, which renders
> it not so qualified as a truly heterogeneous container.
> And by the bye, that it can be used to build a handy pseudo-struct that
> enables full introspection really is a good and fancy feature. However,
> there's something fundamentally irremediable of it, that is, it can't be
> used to build a full-fledged class( rather than a POD-struct), which, I
> think, will too reduce its usefulness w.r.t. this kinda situations.
> I personally very like this fancy facility, and that's why I present
> these mumbles here to annoy you guys( if so, my apologies go here:-))
> Any comments?

I needed basically the functionality of fusion::map to implement a table
of function
pointers. I can't use fusion for this though because I rely on POD

In Christ,
Steven Watanabe

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