[CMake] Feature wish - constrained string values for configuration options

[Bill Hoffman]

Alexander Neundorf wrote:
> On Friday 18 July 2008, Michael Wild wrote:
>> On 18Jul, 2008, at 12:27, Robert Haines wrote:
>>>> I would like to point at my feature wish:
>>>> http://www.vtk.org/Bug/view.php?id=7313
>>>>
>>>> Opinions?
>>> I was looking for this functionality the other day, I think it's a
>>> good idea. I had thought that it was already in there for the
>>> CMAKE_BUILD_TYPE option that you always get but that seems to be
>>> implemented in a different way.
>>>
>>> So +1 from me. Is there anyway I can reflect that in the bug tracker?
>> That would be a very desirable feature. I suggest this be split even
>> further: options with fixed values, like what you get from drop-down
>> menus and options with a set of "proposals", as you get in a combo-box.
>>
>> definitely +1
> 
> This seems to be a duplicate of 
> http://public.kitware.com/Bug/view.php?id=1527 , which is a duplicate of bug 
> 39 according to the note, but I can't find bug 39 anymore :-/
> 

Yup, this is a very old feature request...

However, it is not that easy to implement, since the basic type in CMake 
is a string.  There is no way to constrain the value of a variable, or 
even store more information about a variable.

-Bill