Enhanced Problem_Behavior type

[wdanilo]

This task is automatically imported from the old Task Issue Board and it was originally created by James Dunkerley.
Original issue is here.

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Currently a simple Atom enumeration.

Could become much more like an Error catch

type Problem_Hander
    Ignore = Problem_Handler.Callback (_ value -> value)

    Report_Warning = Problem_Handler.Callback (problem value -> value.attach_warning problem)

    Report_Error = Problem_Handler.Callback (problem _ -> Error.throw problem)

    Callback callback:(Problem->Value->Value) =
        callback problem value = 
            if problem.is_a Encoding_Error then Error.throw problem else
                value.attach_warning problem

    ignore_on : Type -> Problem_Handler
    ignore_on self type =
        callback problem value =
            if problem.is_a type then value else
                self.callback problem value
        Problem_Handler.Callback callback

    warning_on : Type -> Problem_Handler
    warning_on self type =
        callback problem value =
            if problem.is_a type then value.attach_warning problem else
                self.callback problem value
        Problem_Handler.Callback callback

    error_on : Type -> Problem_Handler
    error_on self type =
        callback problem value =
            if problem.is_a type then Error.throw problem else
                self.callback problem value
        Problem_Handler.Callback callback

on_problems=(Report_Warning.ignore_on Encoding_Error)