Is there a way to validate a parameter in param?

Param
1

I want to do something equivalent to:

from pydantic import BaseModel, field_validator

class Test(BaseModel):
    x: int = 1

    @field_validator('x')
    def convert_to_int(cls, value):
        return int(value)  # Convert incoming value to int

# Usage
test = Test(x="3")
print(test.x)  # Output: 3

Using param:

import param


class Test(param.Parameterized):

    x = param.Number(default=1, bounds=(0, 10))

    @param.depends("x", watch=True)
    def _update_x(self):
        self.x = int(self.x)

test = Test()
test.x = "3"

I get:

ValueError: Number parameter 'Test.x' only takes numeric values, not <class 'str'>.

2

I believe you’d have to create a custom parameter, inheriting from param.Number or param.Parameter, then implement your own __set__ and _validate methods.
Easier with param.Number, imo as you just super() the original set and validation logic from param.Number after you handle the conversion.

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