Module: NRSER::Meta::ClassAttrs::ClassMethods
- Defined in:
- lib/nrser/meta/class_attrs.rb
Overview
Class methods to extend the receiver with when NRSER::Meta::ClassAttrs is included.
Instance Method Summary collapse
- #class_attr_accessor(attr, default: NRSER::NO_ARG, default_from: NRSER::NO_ARG) ⇒ Object
- #class_attr_writer(attr) ⇒ Object
- #instance_variable_lookup(name, default: NRSER::NO_ARG, default_from: NRSER::NO_ARG) ⇒ Object
Instance Method Details
#class_attr_accessor(attr, default: NRSER::NO_ARG, default_from: NRSER::NO_ARG) ⇒ Object
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# File 'lib/nrser/meta/class_attrs.rb', line 75 def class_attr_accessor attr, default: NRSER::NO_ARG, default_from: NRSER::NO_ARG var_name = "@#{ attr }".to_sym singleton_class.class_eval do define_method(attr) do |*args| case args.length when 0 instance_variable_lookup var_name, default: default, default_from: default_from when 1 instance_variable_set var_name, args[0] else raise ArgumentError.new NRSER.squish <<-END wrong number of arguments (given #{ args.length }, expected 0 or 1) END end end define_method("#{ attr }=") do |value| instance_variable_set var_name, value end end end |
#class_attr_writer(attr) ⇒ Object
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# File 'lib/nrser/meta/class_attrs.rb', line 104 def class_attr_writer attr var_name = "@#{ attr }".to_sym singleton_class.class_eval do define_method("#{ attr }=") do |value| instance_variable_set var_name, value end end end |
#instance_variable_lookup(name, default: NRSER::NO_ARG, default_from: NRSER::NO_ARG) ⇒ Object
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# File 'lib/nrser/meta/class_attrs.rb', line 28 def instance_variable_lookup name, default: NRSER::NO_ARG, default_from: NRSER::NO_ARG # If it's defined here on self, return that if instance_variable_defined? name return instance_variable_get name end # Ok, now to need to look for it. # See if the superclass has the lookup method if superclass.respond_to? :instance_variable_lookup # It does. See what we get from that. We create a new object to use # as a flag and assign it to `default` so we can tell if the search # failed. not_found = Object.new result = superclass.instance_variable_lookup name, default: not_found # If we found something, return it. return result unless result == not_found end # if superclass.respond_to? :instance_variable_lookup # Ok, nothing was found. # See if we can use a default... if default != NRSER::NO_ARG || default_from != NRSER::NO_ARG # We can use a default. # `default` takes precedence. if default != NRSER::NO_ARG default else send default_from end else # Nope, we can't, raise. raise NoMethodError.new NRSER.squish <<-END #{ name.inspect } is not defined anywhere in the class hierarchy END end # if we have a default value / else end |