require 'delegate'
class Foo
def bar
'Hello'
end
end
class WrappedFoo < DelegateClass(Foo)
def initialize(wrapped_foo)
super
end
def bar
super + ' World'
end
end
foo = Foo.new # this is not actually in your code, it comes from somewhere else
wrapped_foo = WrappedFoo.new(foo) # this is under your control
wrapped_foo.bar # => 'Hello World'
class Foo
def bar
'Hello'
end
end
module FooExtensions
def bar
super + ' World'
end
end
class Foo
prepend FooExtensions
end
Foo.new.bar # => 'Hello World'
class Foo
def bar
'Hello'
end
end
class Foo
old_bar = instance_method(:bar)
define_method(:bar) do
old_bar.bind(self).() + ' World'
end
end
Foo.new.bar # => 'Hello World'
class Foo
def bar
'Hello'
end
end
class Foo
alias_method :old_bar, :bar
def bar
old_bar + ' World'
end
end
Foo.new.bar # => 'Hello World'
Foo.new.old_bar # => 'Hello'
class Foo
def bar
'Hello'
end
end
module ExtendedFoo
module FooExtensions
def bar
super + ' World'
end
end
refine Foo do
prepend FooExtensions
end
end
Foo.new.bar # => 'Hello'
# We haven’t activated our Refinement yet!
using ExtendedFoo
# Activate our Refinement
Foo.new.bar # => 'Hello World'
# There it is!
class Foo
def bar:before
# will always run before bar, when bar is called
end
def bar:after
# will always run after bar, when bar is called
# may or may not be able to access and/or change bar’s return value
end
end
class Foo
def bar:before
# will always run before bar, when bar is called
end
end
# is the same as
module BarBefore
def bar
# will always run before bar, when bar is called
super
end
end
class Foo
prepend BarBefore
end
而且
class Foo
def bar:after
# will always run after bar, when bar is called
# may or may not be able to access and/or change bar’s return value
end
end
# is the same as
class BarAfter
def bar
original_return_value = super
# will always run after bar, when bar is called
# has access to and can change bar’s return value
end
end
class Foo
prepend BarAfter
end