[CMake] cmp0026, file(GENERATE...), and configure_file

[David Cole]

Should it be configure_file(GENERATE or file(CONFIGURE_AND_GENERATE ??

In the meantime, while it is certainly clumsy to do the two separate
commands everywhere, you could write a CMake language
function(configure_file_generate ...) that takes the same args as
configure_file, but does the two step in its implementation.

Then, at least, your clumsiness is reduced, and you can simply replace
configure_file with configure_file_generate everywhere it is
necessary.

I would volunteer to take this on, but I'd be promising my time
falsely. Perhaps another season...


Cheers,
David C.



On Thu, Apr 23, 2015 at 6:13 AM, Alan W. Irwin
<irwin at beluga.phys.uvic.ca> wrote:
> On 2015-04-21 15:54-0400 David Cole wrote:
>
>> I can only imagine that would cause IMMENSE problems.
>
>
> Good point about keeping backwards compatibility, but your shift key
> got stuck.  :-)
>
>>
>> I depend on configure_file being an immediate action in many many many
>> places. (i.e. -- the very next line of code in my CMakeLists.txt file
>> can depend on the result of configure_file being on disk and up to
>> date at the moment of configure processing...)
>>
>> Now, having said that, I could imagine you may want to change *some*
>> configure_file calls to file(GENERATE calls. Or to enable @@
>> substitution in something like an explicit configure_file(GENERATE
>> signature.
>
>
> I think your idea of configure_file(GENERATE...) (where configure_file
> occurs at configure-time without GENERATE to be backwards compatible,
> but it occurs at generate-time if the new GENERATE signature is used)
> is an excellent way to allow users to replace the current clumsiness
> that is required to configure a file with both @ symbols and
> generator expressions.
>
> And to repeat how bad that clumsiness is, two separate commands
> currently have to be used to do the job, and the syntax for those
> commands is very different from each other with one having input file
> first than output file and the other having those reversed with
> special labels for each!  So having the possibility of replacing all
> that clumsiness with configure_file(GENERATE...) would be really nice.
>
> And no I don't have the C++ skills or knowledge of the internal
> workings of CMake to create a patch to implement that, but I hope a
> CMake developer is inspired to do that by this discussion.
>
>
> Alan
>
> __________________________
> Alan W. Irwin
>
> Astronomical research affiliation with Department of Physics and Astronomy,
> University of Victoria (astrowww.phys.uvic.ca).
>
> Programming affiliations with the FreeEOS equation-of-state
> implementation for stellar interiors (freeeos.sf.net); the Time
> Ephemerides project (timeephem.sf.net); PLplot scientific plotting
> software package (plplot.sf.net); the libLASi project
> (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
> and the Linux Brochure Project (lbproject.sf.net).
> __________________________
>
> Linux-powered Science
> __________________________