Re: [Boost-bugs] [Boost C++ Libraries] #799: mpl::if_

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #799: mpl::if_
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2007-07-06 01:50:54

#799: mpl::if_
-------------------------------+--------------------------------------------
  Reporter:  nobody            |       Owner:  nobody     
      Type:  Feature Requests  |      Status:  closed     
 Milestone:                    |   Component:  None       
   Version:  None              |    Severity:  Showstopper
Resolution:  invalid           |    Keywords:             
-------------------------------+--------------------------------------------
Changes (by dave):

  * status:  assigned => closed
  * resolution:  None => invalid
  * severity:  => Showstopper

Old description:

> {{{
> There is an alternative implementation of mpl::if.
> This implementation makes code clearer.
>
> We can write:
> typename if_
> <
>   X,
>   Y
> >
> ::else_if
> <
>   Z,
>   U
> >
> ::else_
> <
>   V
> >::type
>
> The implementation can be found here:
> http://cbear.berlios.de/meta/if.hpp

> }}}

New description:

 {{{
 There is an alternative implementation of mpl::if.
 This implementation makes code clearer.

 We can write:
 typename if_
 <
   X,
   Y
 >
 ::else_if
 <
   Z,
   U
 >
 ::else_
 <
   V
 >::type

 The implementation can be found here:
 http://cbear.berlios.de/meta/if.hpp

 }}}

Comment:

 I disagree; it's far too verbose, and thus less clear, when you consider
 the need for the `template` keyword, which you left out.

 {{{
 #!cpp
   typename if_
   <
     X,
     Y
   >
   ::template else_if
   <
     Z,
     U
   >
   ::template else_
   <
     V
   >::type

-- 
Ticket URL: <http://svn.boost.org/trac/boost/ticket/799#comment:1>
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