Feature #14025
open
Added by frankpimenta (Frank Pimenta) almost 7 years ago.
Updated almost 7 years ago.
Description
For:
class Person
def initialize name = 'person'
@name = name
end
end
I thought that the following would be nice:
class Person
initialize :name
end
class Person
initialize name: 'person', age: 18
end
class Person
def initialize @name="person", @age=18
puts "initializing...something to run before"
end
end
--
B., Frank.
- Tracker changed from Bug to Feature
- Backport deleted (
2.3: UNKNOWN, 2.4: UNKNOWN)
module ObjectInitialization
def self.included base
base.class_eval do
extend ClassMethods
end
end
module ClassMethods
def attr_initializer default_arguments={}
raise RuntimeError.new "No args provided to ::init" if default_arguments.empty?
@@__default_arguments__ = default_arguments
class_eval do
define_method :initialize do |args=nil|
arguments = args.nil? ? @@__default_arguments__ : @@__default_arguments__.merge(args)
arguments.each_pair do |name, value|
instance_variable_set "@#{name.to_s}", value
end
end
end
end
end
end
class Object
include ObjectInitialization
end
class Person
attr_initializer name: 'person', age: 18, address: "somewhere"
end
p0 = Person.new
p1 = Person.new name: "frank"
p2 = Person.new name: "adam", profession: "developer"
I don't quite understand your second example.
class Person
initialize name: 'person', age: 18
Did you not define before that only one argument can be passed?
class Person
def initialize name = 'person'
By the way, I seem to be missing parts of what you are trying to
suggest.
If you mean to initialize @variables by default, similar to what
crystal does, then I think this has been suggested before. I do
not know of the current status either way, but I think that it
may be for ruby 3.x at best due to backwards compatibility (I may
be wrong here too but the ruby core team has said this a few
times before in general).
Where did I define that only one argument could be passed?
I don't want to initialize ivar explicitly in #initialize.
I would like that instead of:
def initialize name='default_name', age=0
@name, @age = name, age
end
I could do either:
def initialize @name = 'default_name', @age=0
end
or as with getter and setters via attr_* :
initialize name: 'default_name', age: 0
What parts do you think are missing? Maybe I already know them but I am trying to find time to fulfil it.
Also available in: Atom
PDF
Like0
Like0Like0Like0Like0