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Subject: Re: [boost] [fusion] useful as_variant in spirit2
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2009-09-25 19:07:01


Christian Holmquist wrote:
> The function in boost\spirit\home\support\detail\as_variant.hpp seems to
> have no dep. on spirit, and it's a useful utility that would fit into
> fusion/support/as_variant.hpp>
> IIUC it's a meta function that computes a variant<T0, ..., TN> from a fusion
> sequence<T0, ..., TN>. I think there's no reason for a runtime counterpart,
> i.e. as_variant<Seq>::type is a valid expression but as_variant(Seq) and
> result_of::as_variant<Seq>::type is not. Thus, the function is already
> complete.
> Does it seem reasonable to you to include in fusion? The work of moving it
> would be to only update the docs, as spirit2 probably does excessive testing
> of this function anyway.
> I could collect the docs from other parts of fusion, and put together a
> separate test file if needed. All real work is already done, just
> presentation and formality that is lacking.

How is this different from boost::make_variant_over?

In Christ,
Steven Watanabe

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