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instance method

Module#method_defined?

mod.method_defined?(symbol, inherit=true) → true or false

mod.method_defined?(string, inherit=true) → true or false

static VALUE
rb_mod_method_defined(int argc, VALUE *argv, VALUE mod)
{
    rb_method_visibility_t visi = check_definition_visibility(mod, argc, argv);
    return RBOOL(visi == METHOD_VISI_PUBLIC || visi == METHOD_VISI_PROTECTED);
}

Returns true if the named method is defined by mod. If inherit is set, the lookup will also search mod’s ancestors. Public and protected methods are matched. String arguments are converted to symbols.

Example

module A
  def method1()  end
  def protected_method1()  end
  protected :protected_method1
end
class B
  def method2()  end
  def private_method2()  end
  private :private_method2
end
class C < B
  include A
  def method3()  end
end

A.method_defined? :method1              #=> true
C.method_defined? "method1"             #=> true
C.method_defined? "method2"             #=> true
C.method_defined? "method2", true       #=> true
C.method_defined? "method2", false      #=> false
C.method_defined? "method3"             #=> true
C.method_defined? "protected_method1"   #=> true
C.method_defined? "method4"             #=> false
C.method_defined? "private_method2"     #=> false

See also #method_added #method_removed #instance_methods #method_undefined also in 4.1 · 4.0 · 3.4 · 3.3 · 3.2 · 3.0

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