使用METHOD_MISSING時請小心

<br />class Dog<br /> def method_missing(method, *args, &block)<br /> if method.to_s =~ /^bark/<br /> puts "woofwoof!"<br /> else<br /> super<br /> end<br /> end<br />end<br /><br />rex = Dog.new<br />rex.bark #=> woofwof!<br />rex.bark! #=> woofwoof!<br />rex.bark_and_run #=> woofwoof!<br />

rex.respond_to? :bark #=> false <= 我們用respond_to? 檢查時會以為沒有這東西
rex.bark #=> woofwoof!

所以要加上 repsond_to?(method) method
<br />class Dog<br />METHOD_BARK = /^bark/<br /> def respond_to?(method)<br /> return true if method.to_s =~ METHOD_BARK<br /> super<br /> end<br /><br /> def method_missing(method, *args, &block)<br /> if method.to_s =~ METHOD_BARK<br /> puts "woofwoof!"<br /> else<br /> super<br /> end<br /> end<br />end<br />rex = Dog.new<br />rex.respond_to?(:bark) #=> true<br />rex.bark #=> woofwoof!<br /><br />