[cmake-developers] CMake policies (was: User vs CMake include mismatch handling)

[Marcel Loose]

Hi Brad, 

>>> On 19-11-2010 at 13:41, in message <4CE6708A.8020406 at kitware.com>,
Brad King
<brad.king at kitware.com> wrote: 
> On 11/19/2010 03:56 AM, Marcel Loose wrote:
>> Slightly off-topic: I couldn't find any references to this
information
>> in the CMake manual.
> 
> That link was a design document.  The actual interface is
documented:
> 
>  
http://www.cmake.org/cmake/help/cmake-2-8-docs.html#command:cmake_policy
>  
http://www.cmake.org/cmake/help/cmake-2-8-docs.html#section_Policies
 
I have read these pieces of information before. However, from these
pages, I couldn't really figure out how policies were supposed to work
-- the whole OLD, NEW, WARN issue. The design document made that much
clearer. So, I think the CMake documentation on Policies could be
enhanced. 

It also wasn't really clear to me which policies are set be default. I
know that for each policy described in the section Policies, there's a
line saying "introduced in CMake <version>", but I didn't know that that
also means that these policies are set to NEW by default when using
CMake <version> or newer. I think a table providing a quick look-up
would really be helpful.

Finally, I think it would be good to cross-reference the commands
cmake_policy and cmake_minimum_required, even though they appear
immediately after one another.

Now that I understand the concepts behind policies, I think it's a
well-designed feature.

Best regards,
Marcel Loose.