Setting `tools` option does not work with Bokeh

Hi, Setting tools as a curve-option does not work with v1.13.4 and Bokeh v.2.2.1. However, setting default_tools does do the trick. Also, both these settings have the exact same description in hv.help(hv.Curve).

This also affects the first example in this documentation page (under “Core concepts”) where the only apparent tools should be "hover".

I suspect it’s like this for a few versions now (since I remember that I used default_tools a few months ago), but still… So either fix the docs, or, better yet, merge these attributes into a single attribute to avoid confusion.

[jlstevens]

The suggestion of tools=[..., "hover"] is perhaps the most outlandish abuse of Ellipsis I have ever seen. 😃

I also agree that the parameter docstrings should be checked and updated to be as clear as possible.

[jbednar]

both these settings have the exact same description in hv.help(hv.Curve)

If that’s true, it should be fixed! Both those options should specifically mention the other one and make it clear how they relate, which is that tools adds additional tools to whatever is in default_tools, and default_tools overwrites the entire starting list of tools.

But I don’t see anything else that should be done; having to list the existing tools explicitly would be very painful, and we can’t change the meaning of tools because that would break backwards compatibility, which would cause at least as much trouble as it solved.

If we didn’t have to worry about backwards compatibility or Python 2, we could imagine supporting some shorthand like tools=[..., "hover"] (where ... would be replaced by HoloViews with the existing tools), but I think that ship has sailed.