[Feature request] Integrate Python docstrings with Julia help

[malmaud]

Not sure how implausible this is, but it would be great if typing
?[python function]
at the julia REPL gave back the docstring of that function/module, just as IPython's ? does.

[stevengj]

help(o::PyObject) of a Python object works to get the docstring. The problem is that there is no documented way to associate help strings with new Julia functions.

The help function internally uses a Base.Help.FUNCTION_DICT dictionary, but I'm not sure if it is kosher to modify this. @StefanKarpinski, @loladiro?

[StefanKarpinski]

Relevant: JuliaLang/julia#3988. I'd really like a proscribed way to do this. cc: @JeffBezanson

[stevengj]

(I think you mean "prescribed". A proscribed technique would not be very useful. ;-)

[StefanKarpinski]

Hahah. Yes, that is what I meant.

[malmaud]

haha

[kskyten]

This is now possible with the @doc macro. Is it possible to apply this to the methods of an object also so that ? object[:method] would provide something useful?

[stevengj]

@MichaelHatherly, I can't figure out how to hook into the @doc macro so that it calls a custom lookup function for a PyObject.

Ideally, it would be enough to just define a Base.Docs.doc(o::PyObject) method (and, in fact, I currently define such a method), but this doesn't work because doc is only called with a Binding object.

Does a hook function need to be added to Base.Docs for custom (lazy) docstring lookup?

[MichaelHatherly]

Does a hook function need to be added to Base.Docs for custom (lazy) docstring lookup?

Something like that might work. I'm not all that familiar with PyCall though, so couldn't say for certain.

[stevengj]

The point is that for o::PyObject, there is a function doc(o) to that returns a help string at runtime (this has to be called "lazily"...i.e., when help is requested, not when the object is created). Is there any way to fix Base.Docs so that this or a similar method could be called when you do ?o?

[MichaelHatherly]

In that case, yes we'd need to add support for that in Base.Docs. I've not got much time at the moment to work on this myself at present though.

[malmaud]

OK, we can do this now!

[stevengj]

Awesome, thanks for getting this in!