[Insight-developers] ITK namespace delimiter discussion

[Brad King]

After some discussion amongst a small group of us off the list, it has
been decided that the ITK_NAMESPACE_BEGIN and ITK_NAMESPACE_END macros may
not be a good idea.  The alternative we propose is to go back to the

namespace itk
{
//...
} // namespace itk

approach, but indent everything inside the namespace by two extra spaces:

namespace itk
{
  //...
} // namespace itk

This would leave the namespace's closing "}" as the only one in the
left-most column, thus making it obvious.  It does, however, take all
function opening "{" and closing "}" characters out of that column, and
indent them two spaces.  It also reduces the number of characters per line
by two before running over the 79 character guideline.

Before I make any changes related to this, I'd like the list to reach a
consensus on which way to go.  The choices that have been proposed are:

// 1
namespace itk
{
// old style, don't indent inside namespace
// requires comment at end of namespace
} // namespace itk

// 2
namespace itk
{
  // new style, indent namespace by 2 characters
} // ending comment optional, only "}" in this column.

// 3  (appropriate macros defined in header)
ITK_NAMESPACE_BEGIN
// no need to indent, no "{" characters appear.
ITK_NAMESPACE_END

// 4  (appropriate macros defined in header)
BEGIN_NAMESPACE (itk)
// no need to indent, no "{" characters appear.
END_NAMESPACE (itk)

Capitalization of macros is up for debate, of course.

-Brad