[cmake-developers] Adding the OpenRAVE library module

[Brad King]

On 04/12/2011 08:02 PM, Rosen Diankov wrote:
> Perhaps I missed something, but FindX.cmake packages will look for
> that, while the configuration method you are suggesting will not.

Correct.  I've been meaning to address this for a long time.

> It would be great if find_package also searches the registry keys for
> the install root.

Yes.  There is a TODO comment in the source code for this:

  http://cmake.org/gitweb?p=cmake.git;a=blob;f=Source/cmFindPackageCommand.cxx;hb=v2.8.4#l2281

One reason it was not done originally is that I did not want to have to
search every vendor's registry namespace for packages.  Since then however
I did add this:

  http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=ed0650f6

in order to work together with this:

  http://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=16ce84b0

I think this design can be generalized to allow installation tools to
add entries.  See below.

> If cmake does not do that, then as you said,  OpenRAVE users will
> still have to copy a small script in order to set the HINTS and PATHS
> variables to find_package. And most likely this script will be called
> FindOpenRAVEConfig.cmake (which will be small and call
> find_package(OpenRAVE) to search for the configuration files).

It will still be called "FindOpenRAVE.cmake".  The application writer
should not have to know how the package is found.  The command

  find_package(OpenRAVE)

will use FindOpenRAVE.cmake if it exists in the CMAKE_MODULE_PATH.
That module is then free to do

  find_package(OpenRAVE NO_MODULE)

to look for OpenRAVEConfig.cmake.

> Therefore, it would be great if FindOpenRAVEConfig.cmake was part of
> the cmake distributions so that users won't have to copy it....

Since you'd have to wait for a new CMake for this anyway, I'd rather just
solve the main problem.  I think this is the prod I needed to try it.
I'll take a look at generalizing the user package registry and get back
to you.

-Brad