Manual rebase of the user friendly setup routine

[ilfreddy]

The new routine takes a few integers as input. It combines them with bit manipulations. The final value corresponds to a unique eval xc_vars. Another integer fixes eval xc_mode. The return statement calls the original xc_eval_setup.

I have not tested it yet. Feedback welcome :-)

Still missing:

• sanity checks for the input integers
• graceful error exit in case the requested combination is not available.
• unit test for the new routine

[codecov-io]

Codecov Report

Merging #74 into master will decrease coverage by 0.26%. The diff coverage is 35.18%.

@@            Coverage Diff             @@
##           master      #74      +/-   ##
==========================================
- Coverage   44.25%   43.99%   -0.27%     
==========================================
  Files          78       78              
  Lines        1785     1839      +54     
==========================================
+ Hits          790      809      +19     
- Misses        995     1030      +35

Impacted Files	Coverage Δ
src/xcfun.cpp	47.68% <35.18%> (-1.79%)	:arrow_down:

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[ilfreddy]

How do I add a test. I tried to copy the example.c but it does not seem to me that it is used anywhere...

[robertodr]

You have to compile it. Follow the example of testall in test/CMakeLists.txt.

[ilfreddy]

Test added.

[ilfreddy]

clang: I think xcfun si far from compliant with any clang style, (I take it back. XCFun is fully compliant, it seems ;-) ) and I am indeed not a fan of it in general. (this still applies! especially for the 2space indent: UGLY!)

Concerning the documentation of the enum, I am not able to do it properly. I think @bast or @uekstrom should consider that in case. I have closed #48. As far as I'm concerned this is good to go.

[ilfreddy]

I tried to extend the coverage of the test but it did not work... :-(