[CMake] Adding Cmake version in online documentation

[Ruslan Baratov]

On 09-Nov-16 23:00, Nils Gladitz wrote:
> On 09.11.2016 15:52, Ruslan Baratov wrote:
>> Can you show the real code? The code that in your opinion doesn't
>> violate the "right way of policy usage"?
>
> It is not a question about code. It is a question about context and
> use case.
You just said that all the code I've showed is not correct and conflicts
with policies nature. So I have to ask you about the real code, because
looks like in your "world" there is no valid case of `cmake_policy`
usage and the only correct way to set policies is to use
`cmake_minimum_required` command. Hence it's not surprising that you
can't distinguish `cmake_minimum_required` and behavior controlled by
`cmake_policy`.

>
> Valid context as the documentation states would e.g. be a project that
> is no longer maintained where you have no intention of ever migrating
> to a newer CMake version.
So why the project in the middle of the migration process is not a valid
case? It is maintained but the exact migration step is paused, but I
have an intention to improve the code in future. Anyway even if the
project is no longer maintained, then what we have? We have
`cmake_minimum_required` with the version that fits **features** the
code has and `cmake_policy` to control the **behavior** of different
cmake versions.

> Or as I said cmake's testsuite.
>
> If you insist on actual code e.g. this is part of the tests that I
> wrote for CMP0054:
> https://cmake.org/gitweb?p=cmake.git;a=blob;f=Tests/RunCMake/CMP0054/CMP0054-NEW.cmake;h=23a912476024ba09fcf741e04f999b64a6e91450;hb=refs/heads/master
>
The internal CMake stuff is out of the scope of discussion. If policies
are the internals why do we need them in the documentation?

Ruslo