Ready for review. But note that I cannot yet run CI on it until RFC-196 is adopted and the pybind11 package is available. Also note that this ticket will not be merged to master after review, but will rather be merged onto the branch for the associated epic where all pybind11 commits will live until a change from Swig is approved.

Also please note that the proposed pybind11 LSST package currently lives on https://github.com/lsst-dm/pybind11

daf_base review: overall this looks very nice. I have a few comments on github. My only requested changse of any significance are:

• Import explicit symbols or the module name instead of using from X import * in exampleLib.py
• Please add _repr_ to the wrapped classes unless repr(obj) and str(obj) already print something useful
• Please support keyword arguments in the constructors, especially if they have multiple arguments

Could you please briefly explain (on this ticket, not as a code comment) what _exampleLib is in this expression: PYBIND11_PLUGIN(_exampleLib). I know it is standard pybind11, but I have not yet figured out what the symbol _exampleLib is or how it is used. It looks like an argument, but it has no type and is not used in the function.

sconsUtils looks fine. I put one minor documentation request on github.

Could you please briefly explain (on this ticket, not as a code comment) what _exampleLib is in this expression: PYBIND11_PLUGIN(_exampleLib). I know it is standard pybind11, but I have not yet figured out what the symbol _exampleLib is or how it is used. It looks like an argument, but it has no type and is not used in the function.

This defines an "extern C" free function named init_exampleLib that's called by Python when the module is imported. All compiled Python extension modules must define a function with that naming convention (i.e. function name is the module name, prefixed with "init") and a specific call signature, and they contain boilerplate for initializing modules that pybind11 handles for us.

Pim Schellart [X] there is no problem adding pybind11 to repos.yaml. You can add any eups packages you want there.

Merged into ticket branch for epic (DM-6168) instead of master.

Made most of the requested changes, except adding keyword arguments for all constructors. I chose not to do this for two reasons:

• It can create ambiguity with overloading.
• I believe the scope of the trial to be limited to provide equivalent functionality. Making our C++ code behave more Pythonically raises design questions and can introduce complications upstream. I thus believe adding keyword arguments for constructors that don't have them on the C++ side to be out of scope. We should return to this after the (possible) migration.