[ANN] PythonCall and JuliaCall

[cjdoris]

@marius311

I tried the CondaPkg / JuliaPkg thing which worked flawlessly. I also discovered I can set JULIA_PYTHONCALL_EXE=$(which python) and JULIA_PYTHONCALL_PROJECT="." to just use an existing Python/Julia enviornment (I’m really liking Poetry on the Python side), which is great for more control. Might be worth documenting this more directly.

Indeed it’s perfectly valid to do that. My next focus is going to be on getting the documentation and testing better. BTW The JULIA_PYTHONCALL_PROJECT variable might go, and instead we’ll just respect JULIA_PROJECT instead if it is set.

@marius311

Is there any plan to have anything like PyCall’s string interpolation py"1+$x" thing? Personally I find it really handy to be able to just paste some unedited Python code into my Julia scripts and have it work. From what I can tell, this might be the only thing holding me back from switching from PyCall/pyjulia entirely.

There is @pyeval and @pyexec.

Your example would become @pyeval x => "1+x".

You can also specify the output type like @pyeval x => "1+x" => Float64.

@marius311

It seems you got around the dreaded pyjulia staticially linked libpython issue, which is great. I admit I don’t actually know the details of why that’s an issue for pyjulia, but still curious if you could say what you did differently to get around that?

I’ve encountered that issue before in pyjulia but don’t actually know its cause.

I imagine the difference is in how the packages load libpython. In JuliaCall, we pass ctypes.pythonapi._handle to PythonCall, which is a pointer to an already-open libpython. I assume PyJulia/PyCall opens libpython itself.

@marius311

Even though its not “needed”, it might still be nice if someone created a “PyPlotCall.jl” package or something, which automatically imported all the standard pyplot stuff and set up Jupyter so you don’t need to return the figure each time.

An older version of PythonCall hooked into IJulia so that matplotlib plots were automatically shown, just like they do in IPython. I could certainly add this back.