Proposal to add context managers to all Layouts + Templates

[ahuang11]

Inspired by @MarcSkovMadsen's comment #6617 (comment)

Many times, I find myself doing something like:

widget_box = pn.WidgetBox(pn.widgets.TextInput())

def process(event):
    try:
        widget_box.loading = True
        ...
    finally:
        widget_box.loading = False

I'm wondering whether we can simplify it:

widget_box = pn.WidgetBox(pn.widgets.TextInput())

with widget_box:
    ...

For templates, it'd be the same:

template = pn.templates.FastListTemplate()
with template:  # disables all
    ...

I think this would work with all layouts, except maybe Swipe (which I think is more fitting to be a Pane).

Additionally, for a future pn.StatusCard (or currently pn.chat.ChatStep), I imagine it would also update the status param on finally.

[ahuang11]

Maybe it can be useful for BooleanIndicators too.

processing = pn.indicators.BooleanStatus(value=False)
try:
    processing.value = True
    ...
finally:
    processing.value = False

with processing:
    ...

[ahuang11]

Ah Philipp mentioned that we could simply use with param.update

import time
import panel as pn

pn.extension()

layout = pn.WidgetBox(pn.widgets.TextInput(), pn.widgets.Button(name="Click me!"))
layout

I think there's no need for this proposal then!

with layout.param.update(loading=True):
    time.sleep(2)
    layout[0].value = "Loaded!"

I think the only need is to document this in the Best Practices guide eventually.

[MarcSkovMadsen]

I have also seen context_managers pn.config.set and .set_values. Would be Nice to align on .update to reduce What you need to remember.

[maximlt]

<obj>.param.update() has been added in Param 2.0 so it's quite recent. It can be used as a context manager or not.