Re: [boost] Formal Review: Template Metaprogramming Library (MPL)

From: Peter Dimov (pdimov_at_[hidden])
Date: 2002-07-18 07:02:39

From: "Aleksey Gurtovoy" <agurtovoy_at_[hidden]>
> Douglas Gregor wrote:
> > The MPL library may be downloaded from:
> >   http://www.mywikinet.com/mpl/mpl_17_jul_02.zip
>
> I fixed some test failures, so here's the new archive -
> http://www.mywikinet.com/mpl/mpl_18_jul_02.zip. An incomplete (Windows
> compilers only) matrix of recent test compilation results is available
from
> here - http://www.mywikinet.com/mpl/log.html.
>
> The updated version has also been checked in the CVS (I was out of sync
for
> a while) - it's still under mpl_v2 branch.

Some quick comments:

"Sequence" doesn't guarantee traversal order... not a big problem, but the
name "sequence" implies order. Unordered collections are typically "bags."

"an algorithm that iterates through the range [begin<s>::type, end<s>::type)
will pass through every element of s;"

... once.

The reference seems incomplete. I haven't found any mention of lambda
expressions, or bind.

No 'sort' algorithm?

Is MPL sequence-based, or is it iterator-based? Let's take for example
'find'. It wants a sequence as a first argument. How do I pass a subrange
(the first half of an existing sequence, say) to it?

The __typeof__ implementation hinted at in vector.html doesn't work for most
(all) existing __typeof__ implementations. They strip references, and
sometimes cv qualifiers.