Dependencies on nested parameters when using `param.watch()` instead of `@param.depends()`

Param
1

Hi,

When I decorate a method in a Parameterized class with @param.depends I can watch nested parameters (as described here), e.g. @param.depends("something.sub", watch=True).

How can I do the same using param.watch()? Because param.watch(my_func, ["something.sub"]) doesn’t work.

Thanks,
Bert

2

Figured it out myself:

import param

class Something(param.Parameterized):

    n = param.Number(default = 2)

    def __init__(self, **params):
        super().__init__(**params)

class App(param.Parameterized):

    x = param.ClassSelector(class_ = Something)

    def __init__(self, **params):
        super().__init__(**params)
        self.x = Something()
        self.x.param.watch(self.test, ["n"])

    # @param.depends("x.n", watch=True)
    def test(self, event):
        print(f"n {event.type} from {event.old} to {event.new}")

app = App()

app.x.n = 5

>>> n changed from 2 to 5