Re: [boost] [parameter] Tutorial checked in

From: Rob Stewart (stewart_at_[hidden])
Date: 2005-07-22 08:35:34

From: David Abrahams <dave_at_[hidden]>
> David Abrahams <dave_at_[hidden]> writes:
> 
> > and the example taking a non-const reference is confusing.  I'll
> > shuffle things around.
> 
> Done.

Much better.

   On the other hand\x{2014}as you may recall from the parameter
   table\x{2014}``color_map`` is an \x{201C}out\x{201D}
   parameter, so it really should be passed by non-const
   reference.

Note that "color_map" and "out" are quoted significantly
differently with no apparent reason.

   A keyword object has a pair of operator= overloads that ensure
   we can pass anything by name, but when an \x{201C}out\x{201D}
   parameter is passed positionally, that's no help: in this
   case, core::depth_first_search would end up with a const
   reference to the color_map and compilation will fail when
   mutating operations are used on it.

That's a long sentence and did you really mean to say "we can
pass *anything*" (emphasis mine)?

Perhaps this would be better:

   A keyword object has a pair of operator = overloads that
   ensure we can pass references to const or non-const objects by
   name, but when an "out" parameter is passed positionally,
   that's no help.  In that case, core:;depth_first_search would
   end up with a...."

-- 
Rob Stewart                           stewart_at_[hidden]
Software Engineer                     http://www.sig.com
Susquehanna International Group, LLP  using std::disclaimer;