[CMake] General modernization facility

[Brandon Van Every]

On Dec 18, 2007 9:36 AM, James Bigler <bigler at cs.utah.edu> wrote:
>
> I also agree that trying to maintain backwards compatibility to the
> detriment of the future can become a hinderance.  I just had a
> collegue who was extreemly frustrated for several hours with why his
> build didn't work, only to discover that he should have been using
> ADD_SUBDIRECTORIES instead of SUBDIRS.  There was no warning from
> CMake stating that he shouldn't be using it (I would argue that CMake
> should warn about the use of SUBDIRS).

General warning facilities, and a standard way of turning on future
looking options, so that people do not have to be stuck in the past if
they don't want to be, would be good.   CMake CVS has the
set_properties(GLOBAL PROPERTIES var1 value1 var2 value2 ...)
mechanism.  So if we didn't bother with the bool(var [value])
interface I proposed, we could selectively apply Alex's patch using
set_properties(GLOBAL PROPERTIES ORDINARY_Y_N_STRINGS TRUE).  Or maybe
someone can think of a better name for it.

Collections of options such as this could be put in a standard module
called "Modern."  include(Modern) would turn on improvements that are
clearly desirable but break backwards compatibility.  Flagging SUBDIRS
as an error would be the kind of thing you'd stick into Modern.  If a
user does include(Modern), they're saying they want whatever is
currently considered the best practice, even if that breaks something.
 It should be clearly documented as having that purpose.

Heh, I wonder if in some instances the opposite would be needed,
include(Ancient) !  :-)  Something that either suppresses appeals to
modernity, or warns vehemently against them.


Cheers,
Brandon Van Every