Replacing a list of sources with an extraction from the target later

Code
1

Sorry for a very rookie question so please flame away.
I had a list of sources that were passed around and I wanted to use target_sources instead so I can use more “elegant” genex processing of including various sources based on build options etc, instead of crude ifs. This works well if I only build the thing.
Now the problem I had overlooked is that this list of sources was also used as input to a custom script. I thought I could then just get the sources out of the target via a property and feed it to the script and it would look the same. Not so easy alas.
Eg one parameter to this script is a semicolon separated list of files which was previously created with separate_arguments(res UNIX_COMMAND "${some_sources};${other_sources}"). The output of this is a list of files with the semicolon escaped, i.e. file1\;file2.
Replacing this with separate_arguments(res UNIX_COMMAND "$<TARGET_PROPERTY:my_tgt,INTERFACE_SOURCES>;${other_sources}") gives the sources from the target as just semicolon separated (not escaped that is) and the sources from ${other_sources} (a conventional list) as a “escaped semicolon” separated string.

Is there some good way of forcing the genex to be evaluated before I call the script so I can post-process it into the required shape? Or is it perhaps better to use some other method than this unorthodox usage of separate_arguments to create an “escaped semicolon” separated string?
Or perhaps I should just keep the list of sources and avoid the genexing.

2

You can use file(GENERATE) and $<LIST:JOIN,...,...> to solve the generator expressions and convert it to space separated for use in a script.

3

Thanks. Would this entail then putting the list in this file and then reading it back up again to have it evaluated? If so I think that’s enough overhead so I’ll just stick with a non-genex list floating around :).

4

You wrote that. Maybe you can show how that file list interacts with your script?

5

Yes, so I just tried to say that if I have to change the interface to this script (to read from a file instead of taking a parameter) then I’ll refrain from the change. It’s a custom python script that takes a bunch of parameters, one of them being a semicolon-separated string of source file names.
A little pity that the genex style comes with a few rather hard-to-swallow differences and/or drawbacks from using temporary variables.

6

Have it take them as separate arguments. You can then just use unquoted CMake expansion (possibly with VERBATIM) to get proper empty element dropping and quoting.