Migrate express and AbstractRepresentation type from QuantumSymbolics

[apkille]

QuantumSavory/QuantumSymbolics.jl#92

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 16.95%. Comparing base (3d63b38) to head (7ce478a).
Report is 11 commits behind head on main.

Files with missing lines	Patch %	Lines
src/express.jl	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #46      +/-   ##
==========================================
- Coverage   17.29%   16.95%   -0.34%     
==========================================
  Files          12       13       +1     
  Lines         399      401       +2     
==========================================
- Hits           69       68       -1     
- Misses        330      333       +3     

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[apkille]

Just a note: I moved

express(obj) = express(obj, QuantumOpticsRepr()) # The default representation

to here from QuantumSymbolics to avoid type piracy in QuantumSymbolics. This isn't urgent whatsoever, but I wonder how beneficial it is to have a default representation for express, given that the ecosystem of packages supported by QuantumInterface is growing. This might be a bad comparison, but it's kind of like if DifferentiationInterface were to make its default backend AutoForwardDiff because ForwardDiff.jl has been around a long time and is used by a lot of people. Those things are true and ForwardDiff.jl is quite a handy package, but there's a ton of other autodiff packages that someone might rather use instead. I think the same could be said here. It probably would be a clearer translation interface if the user always has to explicitly define what backend they want to plug into. Of course, this would be a breaking change, but I thought I should put that thought out there.

[apkille]

@Krastanov

[Krastanov]

Looks good. I posted more comments in QuantumSavory/QuantumSymbolics.jl#93

Only other thing here: could you add a

"""
Some short explanation
"""
function express end

after a bump of the version to 0.3.x+1 I can merge this and let you finish the one in QuantumSymbolics.

Do you have merge privileges for this repo?

[Krastanov]

Marking it as a draft to remove it from my review queue for now. Convert it back when ready and merge (or ping me to merge).

[apkille]

@Krastanov should be good to go. I don't have merge privileges for QuantumInterface.

[Krastanov]

the kwdef error is because this was made public in 1.9. Prefacing it with Base.@kwdef should be enough

[Krastanov]

the jet errors are also on master. Could you bump the ignore count to 3. There are ways to make this more robust, but I have not had a chance to look into it yet

[Krastanov]

Just FYI, make sure that on similar PRs in the future you use "Squash and Merge" not "Merge", to keep the git history neat and easy to review. On most of the QuantumSavory repositories that is the default, but it is not the default here.

Of course, if you have neatly separated commits in your PR, just use "Merge". For folks that like to have neat commits in their PRs, they would usually add small fixes "junk" commits, have a reminder in the commit title (e.g. fixup: <actual title>) and then they would use rebase+squash to clean up before merging.

[apkille]

Ah my bad, sorry about that. I'm so used to it being the default that I just pressed the green button. Thanks for the heads up.