[Insight-developers] Namespace / file extension conversion.

[Brad King]

At the meeting this past week, it was decided that two major changes to
the ITK source tree will be made:

1.)  The .cxx files that actually define members of templated classes and
are included in a #ifndef ITK_MANUAL_INSTANTIATION block within the
corresponding .h file will be re-named to have the extension .txx

2.)  Class names will no longer be prefixed with "itk".  Insetead, they
will be placed inside the "itk" namespace.  This means that all source
other than #include lines (for the most part) will need to be in a

namespace itk
{
....
}

block in each file.

Both of these will be broad changes to Insight, so I plan to make all the
changes at once on a compiling, most recent version of the source
tree.   If any developers have classes in progress, please make sure they
are checked in by 12:00 noon on Tuesday, June 26.  After this time, please
do not update or modify your copy of the source until I send out another
message declaring that the changes are complete.  I expect it to take
about 1 day to change everything.  If this deadline is a problem, please
let me know before it is reached.

As an example of the changes that will be made for the namespace
conversion, I have already checked in a new version of the Mesh, Cell, and
Container classes which are now defined in the "itk" namespace.  Note that
within the namespace, an "itk::" qualifier is not needed to access the
classes.  Anything outside ITK, such as test programs, must use this
qualifier to get at ITK classes (for example, itk::Mesh<int>).

Thanks,
-Brad King