Re: [boost] [fusion]bug: as_list on cons list is identity

From: Larry Evans (cppljevans_at_[hidden])
Date: 2008-02-06 10:19:17

On 02/06/08 08:59, Larry Evans wrote:
> On 02/06/08 01:21, dan marsden wrote:
>> Larry Evans <cppljevans_at_[hidden]> wrote:
[snip]
>>
>> Does this lead to a problem in your code? The sequence of cons cells is a list 
>> (fusion::list can be seen as just a convenient way of building a long cons cell sequence).
[snip]
>>
> Thanks dan, you're right, it doesn't make a difference,
> as I just found out.
> 
> It appears the original problem was using mpl::filter_view
> then mpl::transform on that result, and this lead to a wrong
> result.  I'd jumped to the conclusion that the problem was
> the fusion cons list, but my recent test results indicate
> that the problem is in mpl::filter_view.
Nope, I was wrong again.  Although the printout of the transform
appears different from:

   mpl::vector<T0,T1,Tn>

it behaves the same w.r.t. mpl::for_each.

Lesson:  Don't rely on typename printout's to compare
equality of types.  Use mpl::equal.