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class Form
def initialize
@click = Event.new
end
def click
puts "TRACE: Click"
@click
end
def click=(x)
puts "TRACE: Click=#{x.inspect}"
if x.instance_of? MethodHolder then
@click.add(x.method)
else
@click.set(x)
end
end
end
class MethodHolder
attr :method
def initialize(m)
@method = m
end
end
class Event
def initialize
@methods = []
end
def +(m)
puts "TRACE: +(#{m.inspect}"
MethodHolder.new(m)
end
def call
@methods.each { |m| m.call }
end
def add(m)
@methods << m
end
def <<(m)
@methods << m
end
def set(m)
@methods = [m]
end
def delete(m)
@methods.delete m
end
alias :add,:push
alias :remove,:delete
end
def bar
puts 'hello'
end
def baz
puts 'world'
end
form = Form.new
form.click += method(:bar)
form.click += method(:baz)
form.click.call
|
