Replace show_labels with a label formatter

[ceball]

Currently not doing anything?

Default to capitalizing, and replacing underscore with space.

[ceball]

@jlstevens, I assume this issue can be closed now thanks to your recent work?

[jlstevens]

Formatting labels was addressed in #48 but the code above regarding the show_labels parameter was left unchanged. I'll rename this issue to reflect what I think is still a problem...

[jlstevens]

Ah the title is 'replace show_labels with a label formatter'. I'm not sure why you would want to do that. Even more fundamentally, why would you ever want to disable the labels entirely? How would you know what parameter each widget affects?

In other words, what was show_labels supposed to do? It doesn't make sense to me as a concept and I'm happy to make a PR to remove this parameter entirely (or issue a warning for backwards compatibility).

[ceball]

I don't know what show_labels was supposed to do as I didn't add it, but it appeared to me that it did nothing; this issue was about removing show_labels and adding a label formatter. So I think we're agreeing.

[jbednar]

I think this issue can be closed with no further changes. If someone instantiates Widgets with only one Parameter or with only widgets that need no name (e.g. dates or action buttons), they may or may not want space reserved for any form of label at all. So I think show_labels is useful completely independently of label formatting.

[jbednar]

Oh, except that show_labels appears to be a no-op above? That code does look bogus, and I think show_labels=False should be entirely disabling all labels not inside the widget itself, in which case this issue still remains open.

[jlstevens]

I think show_labels=False should be entirely disabling all labels not inside the widget itself

Right though why would this be useful?

[jbednar]

As said above; if you just have one widget controlling a plot, you might want to put whatever label you like in the page template, not be forced to use ParamBokeh's labelling.

[jlstevens]

I see what you mean now but it still strikes me as a sufficiently rare enough use case that I'm not convinced it warrants a separate parameter.

You could just set a label formatter that returns an empty string which seems to have been the original intent of this issue. Have we ever needed to use this parameter ourselves? Probably not as it doesn't work!

[ceball]

I'm sure I've used no labels before (not with parambokeh, though - probably paramtk). Whether to have a separate parameter for it, or to do it via the label formatter (as I meant with this issue originally), or to do it with some other parameter we might also want like a label position parameter (probably not), I'm not sure. My opinion seems to vary depending what other system I've been using most recently. And I haven't been able to look at the label formatter yet.

[jlstevens]

Given the parameter already exists, I might as well make a PR to get it working even if I don't see much value in it (at least not yet!).