Re: [Boost-bugs] [Boost C++ Libraries] #6760: PUSH_BACK/_FRONT on empty array broken

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #6760: PUSH_BACK/_FRONT on empty array broken
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-04-03 21:39:48

#6760: PUSH_BACK/_FRONT on empty array broken
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  Reporter:  yves.pausch@…          |       Owner:  pmenso57    
      Type:  Bugs                   |      Status:  closed      
 Milestone:  Boost 1.50.0           |   Component:  preprocessor
   Version:  Boost 1.49.0           |    Severity:  Problem     
Resolution:  invalid                |    Keywords:              
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Comment (by frank.richter@…):

 The reference docs make no statement about the validity of empty tuples or
 arrays. Only one place makes an implication: “Sequences are data
 structures that merge the properties of both lists and tuples with the
 exception that a seq cannot be empty.” - the implication being that lists
 and tuples (and thus by extension arrays) _can_ be empty.

 So now you stated tuples (and by extension arrays) cannot be empty.
 Judging from the list documentation, an empty list is not possible, either
 (as I read it, the tail can be BOOST_PP_NIL, but it's stated the head can
 only be an element).

 So what container _can_ be empty? The documentation doesn't say. And at
 least until 1.49 and empty array was a working solution. So if you're not
 planning to provide some support of zero-element tuples/arrays, at the
 very least consider the whole thing a documentation issue, and that some
 more explicit words on empty containers would be desireable.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6760#comment:4>
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