Easy specification of dimensions for hover tool

Instead of building an explicit hover tool to choose dimensions to show hover information for, maybe we could have a syntax such as:

tools=['hover+time|voltage']

Where + means you are building a whitelist (what to include) and - means it is a blacklist (what to exclude). E.g to exclude ‘time’ and ‘voltage’:

tools=['hover-time|voltage']

[jbednar]

Sounds like we could support a general mechanism for Bokeh tools where we generalize our tools parameter to accept tuples, i.e. something like tools=['tool1', ('tool2', settings2), ('tool3', settings3)]. To implement that per tool, we’d register a handler for that tool that maps the given settings into configuration for that tool. For hover, what the handler would do is accept a string (i.e., HTML template), list (i.e., list of dimensions), or dict (i.e., list of dimension:formatter pairs) specification, and would map that into the tooltips argument of HoverTool. Other tools could be configured similarly. Something for you to attack, @jlstevens ?

[jlstevens]

That final suggestion seems pretty reasonable to me. The only think I would like is for there to be a clear mechanism that maps a string (e.g. ‘pan’, ‘wheelzoom’, ‘hover’) to a Bokeh tool model or the tuple format (e.g. ('hover', ['col1', 'col2']) which should also support the HTML template). I’m not sure what would be customized for other tools but I would hope to make this mechanism general for all the tools…