Class: Zemu::ConfigObject

Inherits:
Object
  • Object
show all
Defined in:
lib/zemu/config.rb

Overview

Abstract configuration object. All configuration objects should inherit from this.

Direct Known Subclasses

Config, Zemu::Config::BusDevice

Instance Method Summary collapse

Constructor Details

#initialize(&block) ⇒ ConfigObject

Returns a new instance of ConfigObject.


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# File 'lib/zemu/config.rb', line 21

def initialize(&block)
    if self.class == Zemu::ConfigObject
        raise NotImplementedError, "Cannot construct an instance of the abstract class Zemu::ConfigObject."
    end

    @initialized = false

    # Initialize each parameter to nil
    params.each do |p|
        if params_init[p].nil?
            instance_variable_set("@#{p}", nil)
        else
            instance_variable_set("@#{p}", params_init[p])
        end
    end

    # Instance eval the block.
    instance_eval(&block)

    # Raise a ConfigError if any of the parameters are unset.
    params.each do |p|
        if instance_variable_get("@#{p}").nil?
            raise ConfigError, "The #{p} parameter of a #{self.class.name} configuration object must be set."
        end
    end

    @initialized = true
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(m, *args, &block) ⇒ Object

This allows some metaprogramming magic to allow the user to set instance variables (config parameters) while initializing the configuration object, but ensures that these parameters are readonly once the object is initialized.


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# File 'lib/zemu/config.rb', line 53

def method_missing(m, *args, &block)
    params.each do |v|
        # We don't allow the setting of instance variables if the object
        # has been initialized.
        if m == "#{v}".to_sym
            if args.size == 1 && !@initialized
                instance_variable_set("@#{v}", args[0])
                return
            elsif args.size == 0
                return instance_variable_get("@#{v}")
            end
        end
    end
    
    # Otherwise just call super's method_missing
    super
end