zgm (zhouguangming) · 回帖

1:
One called with Hello 
2:
##
Example
one
*****
3.1:
@@@
two

$$$$
3.2:
##
Example
two
*****
3.3:
@@@
two
true
$$$$
4:
==> calling one with ["GoodBye"]
One called with GoodBye
<== one returned nil
5:
==> calling two with [4, 5]
<== two returned 9
9

分析

1.
ex1.one("Hello")  => # 打印 1
2.
include TraceCalls =>
self.included(klass) => 
wrap(klass, existing_method) => 
def self.wrap(klass, method)
  # 打印 2
  puts "###{}"
  puts klass
  puts method
  puts "*****"
  # 结束打印 2
  klass.instance_eval do
     method_object = instance_method(method)
     define_method(method) do |*args, &block|
        puts "==> calling #{method} with #{args.inspect}"
        result = method_object.bind(self).call(*args, &block)
        puts "<== #{method} returned #{result.inspect}"
        result
     end
  end
end

3.
def two(arg1, arg2)
   arg1 + arg2
end
=>
def klass.method_added(method)
    # 打印 3.1
    puts "@@@"
    puts method
    puts @trace_calls_internal
    puts "$$$$"
    # 结束打印 3.1
    unless @trace_calls_internal
       @trace_calls_internal = true
       TraceCalls.wrap(self, method) =>(
       def self.wrap(klass, method)
          # 打印 3.2
          puts "###{}"
          puts klass
          puts method
          puts "*****"
          # 结束打印 3.2
          klass.instance_eval do
             method_object = instance_method(method)
             define_method(method) do |*args, &block|
                puts "==> calling #{method} with #{args.inspect}"
                result = method_object.bind(self).call(*args, &block) 
                puts "<== #{method} returned #{result.inspect}"
                result
            end =>(
            def klass.method_added(method)
              # 打印 3.3
              puts "@@@"
              puts method
              puts @trace_calls_internal
              puts "$$$$"
              # 结束打印 3.3
              unless @trace_calls_internal
                @trace_calls_internal = true
                TraceCalls.wrap(self, method)
                @trace_calls_internal = false
            end
          end
          )
        end
      end
       ) 
       @trace_calls_internal = false
    end
    # 结束打印 3
end

4. 
ex1.one("GoodBye") => 

define_method(method) do |*args, &block|
    #  打印 4
    puts "==> calling #{method} with #{args.inspect}"
    result = method_object.bind(self).call(*args, &block)
    puts "<== #{method} returned #{result.inspect}"
    # 结束打印4
    result
end

5. puts ex1.two(4, 5) =>

define_method(method) do |*args, &block|
   # 打印 5
   puts "==> calling #{method} with #{args.inspect}"
   result = method_object.bind(self).call(*args, &block)
   puts "<== #{method} returned #{result.inspect}"
   # 结束 打印 5
   esult
end