[Core]"Merge" functionality

[RiccardoRossi]

As pointed out by @philbucher and @loumalouomega we have an outstanding problem with the current settings mechanism:

let's imagine that we have a "base_class"

 class base_class:
        self.default_settings = Parameters({
           "A":2,
           "B":3,
           "C":4
        }

we would like now to define a "derived_class" and to override some of the default settings or add new defaults for example so to achieve:

 class base_class:
        self.default_settings = Parameters({
           "A":200, ---> overridden
           "B":3,
           "C":4,
           "D":300 --> added
        }

currently we would need to replicate all the settings or to add/merge them by hand. This is cumbersome and error prone.

I think it would be good to have the parameters to provide such capability using a "DeriveSettings" functionality (not a good name, Merge would be also a candidate...). Long story short the idea would be to be able to write

  class DerivedClass(BaseClass):

           self.default_settings.Merge( 
                  Parameters( """
                  {   
                       "A": 200, --> this one exists in the default_settings so that we shall override it
                       "D": 300 --> this does not exist in the default_settings so that we shall add it 
                  }
                  """)

[philbucher]

+1 from my side, since we discussed this in person already

[pooyan-dadvand]

An important feature! 👍

[pooyan-dadvand]

Is this can be solved with #3889?

[loumalouomega]

Is this can be solved with #3889?

No, but can be done easily (at least easier than before) using that

[roigcarlo]

Closing, repoen if necessary.

[philbucher]

I forgot to mention, this is kinda implemented in #4736