Simplify find_packages example

[bast]

Currently we have TBB and Armadillo but I am not sure too many participants can relate to these libraries. I am brainstorming about a simpler example where we possibly detect a package or library that we have created ourselves. I am brainstorming/working on this this week @blindij.

[blindij]

My motivation for TBB was to show that you could test a library/package in three steps:

1. Download and unpack
2. Go looking for the Config.cmake
3. Use it by hinting to find_package()about the path the Config.cmake

This is not completely true, since you must refer to the package name either by name (TBB::tbb) or
variable ${TBB_IMPORTS}, and you must at least look at README to find the name of the variable.

[bast]

OK I will have a careful look. Of course I don't want to remove a good example. So what is it that we try to achieve precisely in this exercise? I hope this is not a silly question: I would really like that we are clear about the goal of this and then we can assess whether this is a good example.

[bast]

Because my feeling was that we want to demonstrate how find_package works. But let us sharpen the goal first.

[blindij]

You want to try out a package/library from somebody else. find_package() ease the process, but you need to know where to look( use of the hint) and you need to know the name of the library in CMake context. In the TBB case, it is TBB::tbb or ${TBB_IMPORTS}

[bast]

OK so the goal of this exercise is to demonstrate find_package to locate an external package and we want to demonstrate that it might be necessary to provide hints to the find functions? Because if yes, then I think we can demonstrate this with some super simple example and can possibly avoid explaining what TBB is and going into TBB internals (like TBB_IMPORTS).

[blindij]

Yes.

[bast]

OK let's see what I come up with - I use this week as CMake week and will go through entire lesson and try to simplify and motivate more.

[blindij]

What about starting with CMake, and then do the Makefile, since we use Make to build anyway? Hence make becomes a kind of detour, before we go deeper into make.

[bast]

The motivation for starting with Make was to cater to Python/R folks and to understand why Makefiles exist and then arrive at limitations of Make and motivate CMake. Then some Python/R participants may switch off. If we do it the other way, my worry is that we might not reconnect to the interpreted language folks at all.

[bast]

My goal was to show: Make is for everybody, CMake is for all those who compile.

[bast]

I think this is solved/outdated now since the lesson evolved a lot since.