Re: [Boost-bugs] [Boost C++ Libraries] #4209: Visualizer VS 2008 to boost::unordered_map

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #4209: Visualizer VS 2008 to boost::unordered_map
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-11-03 16:42:46

#4209: Visualizer VS 2008 to boost::unordered_map
------------------------------------+---------------------------------------
  Reporter:  fernandoofj@…          |       Owner:  danieljames
      Type:  Feature Requests       |      Status:  closed     
 Milestone:  To Be Determined       |   Component:  unordered  
   Version:  Boost 1.42.0           |    Severity:  Cosmetic   
Resolution:  wontfix                |    Keywords:             
------------------------------------+---------------------------------------

Comment (by brian.ventre@…):

 I started looking at this yesterday, and haven't gotten very far, but
 wanted to add what I have found so that others can start somewhere.

 So far, the original attached file has mostly worked for me under
 VS2005SP1 (only tested unordered_set & unordered_map).  However, as one of
 the earlier posters noted, it does not work for the case:
 {{{
 boost::unordered_map<int, boost::unordered_set<int> >
 }}}
 The problem is the `$T2` substitution.  When VS does the text substitution
 in the pointer cast, it simply replaces `$T2` with the second template
 argument.  The problem is the ambiguity with templates and the `>>`
 string.  The original line is:
 {{{
 ((std::pair<$T1 const ,$T2>
 *)(boost::unordered_detail::value_base<std::pair<$T1 const ,$T2> >
 *)(boost::unordered_detail::hash_node<std::allocator<std::pair<$T1 const
 ,$T2> >,boost::unordered_detail::ungrouped> *)&$e)
 }}}
 If you have a plain map, like say `unordered_map<int,int>`, then this
 expands to:
 {{{
 ((std::pair<int const ,int>
 *)(boost::unordered_detail::value_base<std::pair<int const ,int> >
 *)(boost::unordered_detail::hash_node<std::allocator<std::pair<int const
 ,int> >,boost::unordered_detail::ungrouped> *)&$e)
 }}}
 VS is ok with this, and the visualizer works.  If you have a map where the
 second template argument is itself a template, (like
 `unordered_map<int,unordered_set<int> >`), you get:
 {{{
 ((std::pair<int const ,unordered_set<int>>
 *)(boost::unordered_detail::value_base<std::pair<int const
 ,unordered_set<int>> >
 *)(boost::unordered_detail::hash_node<std::allocator<std::pair<int const
 ,unordered_set<int>> >,boost::unordered_detail::ungrouped> *)&$e)
 }}}
 VS is NOT ok with this.  The problem is in the `>>` that results due to
 the plain text substitution it performs.  A workaround would be to add a
 space after each instance of `$T2` in the original line:
 {{{
 ((std::pair<$T1 const ,$T2 >
 *)(boost::unordered_detail::value_base<std::pair<$T1 const ,$T2 > >
 *)(boost::unordered_detail::hash_node<std::allocator<std::pair<$T1 const
 ,$T2 > >,boost::unordered_detail::ungrouped> *)&$e)
 }}}
 This fixes the case where the second template argument is itself a
 template, but breaks the first case (where it is not).  So, with all of
 this, you can have one or the other (templates or no templates...).

 My naive workaround (and I don't have it in front of me, sorry), is to
 double up the entire `#array` statement, with one version being the "with
 spaces" and one the "without".  This means you end up with double the
 elements in the visualizer, half of which are always `(error)`, while the
 other half are correct.  That gets me at least half-way there, while being
 more expensive with screen real-estate.

 Hope this helps anyone else who stumbles across this page.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4209#comment:9>
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