The end of header only

[uphoffc]

The goal of this pull request is to make easi a non-header-only - i.e. classic - library. Why? Because header-only is essentially BS for easi and I dunno why I did that in the first place.

Pro:

• faster compile times in user code
• symbols are only defined once (You were in deep trouble if you include easi in two separate libs and then try to link these together. The problem is real in exahype which is why there is a branch compiled_lib, which fixes some problems but is only halfway finished.)
• header-only was a garbage idea from the beginning as you have to link against yaml-cpp and impalajit such that you cannot just drop in the easi headers and be done - which is the whole point of header-only

This PR is pretty heavy but there are no actual code changes besides moving things around. (With the exception of YAMLComponentParsers.) However, almost every line of code changes, because

• Well I had to move code in the cpps
• I fixed all includes while I was at it
• I applied clang-format for extra beauty (yes it messes up the history a bit but I think the history is not so valuable in this project)

Moreover, I started to create some nice install stuff. The ultimate goal would be that you can write

find_package (easi)
add_executable (test test.cpp)
target_link_libraries(test easi::easi)

in your user project. However, that does not quite work yet due to the dependencies. I'll further look into this but I would be nice to get some help from @krenzland here (after his vacation!!1).

[Thomas-Ulrich]

Hi,
That's sounds great.
But why not applying clang formatting to the current master branch, and then merge your changes by the updated master (at least give a try)?
That would facilitate reviewing your PR (not that I have the capacities to do that ^^).

[uphoffc]

Ah I guess that's tricky to do, but the following should do what you request:
https://github.com/SeisSol/easi/compare/606357c0a193c1d10a5d513ea3ef872ec7277b22..66d3cd7f01f01a5c17f5df7072b9ae6efef588c9

[Thomas-Ulrich]

Hi,
Do you need some testing on this PR? How can I help?

[uphoffc]

Unit tests still run :-)

[Thomas-Ulrich]

Then should we merge?

[uphoffc]

@krenzland is going to have a look at the cmake part then we merge

[Thomas-Ulrich]

How difficult would it be to have python bindings when the PR is merged? Would be quite useful ;-)

[uphoffc]

Wouldn't do it with this PR but its a good idea!

[krenzland]

Python bindings are relatively easy and can even be auto-generated with e.g. https://github.com/pybind/pybind11

[krenzland]

Some very small things. Not sure if everything is perfect but it is definitely better than the status quo :)
Thanks!

[krenzland]

Shouldn't we require a more modern version? 3.9 is pretty old...

[uphoffc]

Suggestions?

[krenzland]

3.16 is on NG. The workstations at LRZ have 3.10 at least. I have 3.20 on my laptop.
-> Use the version that you are using to test it?

[uphoffc]

tested 3.13