Supporting panel widgets directly as streams

HoloViews supports turning parameters directly into streams such that DynamicMaps update when parameter values change (the parameters are promoted to a Params stream internally). Panel widgets are also based on param and I was hoping to use this support to drive a DynamicMap with panel widgets. Unfortunately, as soon as you try to use more than one panel widget this way, you encounter name clashes as all widget value parameters have the same name (namely widget.param.value).

Given that parameters can be used as streams, I would like to use param widgets directly as well, using the widget name (or some sort of identifier label which I think would be useful in Panel more generally e.g to select a specific widget out of a bank of widgets by name) as follows:

import panel as pn
import holoviews as hv
hv.extension('bokeh')

checkbox = pn.widgets.Checkbox(name='My Checkbox')
selector = pn.widgets.Select(options=['a','b','c'], name='My Selector')

def callback(my_selector, my_checkbox):
    return hv.Curve([1,2,3])

hv.DynamicMap(callback, streams=[checkbox, selector])

This would be orthogonal to other approaches such as pn.bind (which should also be available from param, without special widget support). For me this approach would feel very natural and I don’t think it precludes any other of the available approaches.

[jlstevens]

One idea I quite like is to note that the streams parameter only supports lists for historical reasons:

    streams = param.List(default=[], constant=True, doc="""
       List of Stream instances to associate with the DynamicMap. The
       set of parameter values across these streams will be supplied as
       keyword arguments to the callback when the events are received,
       updating the streams.""" )

Supporting a dict here would take a lot of the pain away imho and would be a great improvement for HoloViews generally (and would avoid the need for bind in many cases):

checkbox = pn.widgets.Checkbox(name='My Boolean')
selector = pn.widgets.Select(options=['a','b','c'], name='My Value')

def callback(selector, like_and_subcribe):
    return hv.Curve([1,2,3])

hv.DynamicMap(callback, streams=dict(selector=selector_widget, like_and_subcribe=checkbox))

Implementing this would make this issue mostly moot as this dict could support parameters or panel widgets as values (holoviews streams here become tricky for streams with multiple parameters).

[philippjfr]

I still think panel widgets should be allowed to have user specified identifiers.

Please file an issue about that. We do have a mechanism to query any panel object for subobjects matching some criteria using the .select method (modeled after bokeh’s Model.select) and I would quite happily support for having an id attribute or similar. The main concern here is that it cannot clash with any existing parameter in Panel.