overwrite default value of base class parameter within derived class

[arndflatten]

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Question

Some class A has an addRequiredParam("pName","pDescr") defined inside its A::validParams().

My subclass B wants to make this pName an optional parameter and set some default value for it, but I dont see how, despite there must be a simple solution?

I tried

InputParameters
B::validParams()
{
  InputParameters params = A::validParams();
  params.makeParamNotRequired("pName");
  if(!params.isParamSetByUser("pName"))
    //* no such thing as setParam("pName", pValue) exists? So trying to add again:
    params.addParam("pName",newDefaultValue,"pDescr");
  return params;
}

but this doesn't take the newDefaultValue when i omit to define the pName in the input file. What am I missing out?

[GiudGiud]

in the validParams, you can re-add the parameter with a valid value

params.addParam<param_type (same as before!)>("pName", newDefaultvalue, "Description");

The if condition you have there should not be necessary.

isParamSetByUser is not meant for use in validParams

[arndflatten]

Thank you. So, if i need to re-add the parameter again, also the params.makeParamNotRequired("pName") is not necessary, right?

And is there a way, how I can retrieve the <param_type> and "oldDescr" from the original baseClass-parameter automatically?
Is the re-adding approach the considered-best way to achieve something like i want, or, is there an alternative way like using some params.setDefaultValue("pName",pDefaultValue) that I just overlooked?

Thanks again!

[GiudGiud]

I don't think there is a way to retrieve the parameter type.
You might be able to get the name by looping over the validParamsnof the base class