How to do imports in global scope?

[marius311]

I'm trying to do something like

@pyexec """
import numpy as np
"""

@pyexec "np.array([1,2])"

Is this possible and if so how?

[cjdoris]

@pyexec always runs in a local scope. I think putting global np at the top of the first call does what you want.

Alternatively pyexec("import numpy as np", @__module__) works in global scope unless you provide a local scope in the 3rd arg.

Btw there is no distinction between single- and multi-line code (unlike PyCall's py"..." macro). You probably want @pyeval for your second call.

[marius311]

Got it, thanks. May I suggest making an easier-to-read version of this? Seems like putting a bunch of imports at the top of a script or module is pretty typical. What about this?:

@pyexec @__MODULE__ """
import numpy as np
""" 

[cjdoris]

I used to have essentially this, but removed it because it doesn't really add anything you can't do by other means (using global np or pyexec(...)) - and I'm trying to make the API smaller not bigger.

[marius311]

Its up to you, but fwiw I would just say this is so common with imports at the top of a script / module that its a shame to need the harder-to-read:

pyexec("""
import numpy as np
""", @__MODULE__)

(as well as break the consistency assuming most of your other code is using the macro).

But if you don't like that, maybe another idea is for the macro to actually enforce Python scope to match Julia scope? A macro can tell if its being called in a top-level scope, so its entirely possible to make this work as you'd expect:

module Foo

@pyexec """
import numpy as np"
global_var = 1
"""

function foo()
    @pyeval "np.array([1,2,3])"
end

end

function bar()
    @pyexec "x = np.array([1,2,3])"
    @pyeval "x"
end

function baz()
    @pyeval "global_var" # OK
    @pyeval "x" # error, even after calling bar()
end

end 

schematically, you'd have the macro generate something like:

if !@isdefined(@__MODULE__.__py_globals__)
    global __py_globals__ = PyDict()
end

if !@istoplevel() && !@isdefined(__py_locals__)
    __py_locals__ = PyDict()
end

pyexec(..., __py_globals__, (@istoplevel() ? __py_globals__ : __py_locals__))

Would be more complex if you wanted to handle inner functions, although probably doable.