instance method

Object#define_singleton_method

(::interned name, ::Method | ::UnboundMethod | ::Proc method) -> ::Symbol

(::interned name) { (?) [self: self] -> untyped } -> ::Symbol

define_singleton_method(symbol, method) → symbol

define_singleton_method(symbol) { block } → symbol

static VALUE
rb_obj_define_method(int argc, VALUE *argv, VALUE obj)
{
    VALUE klass = rb_singleton_class(obj);
    const rb_scope_visibility_t scope_visi = {METHOD_VISI_PUBLIC, FALSE};

    return rb_mod_define_method_with_visibility(argc, argv, klass, &scope_visi);
}

Defines a public singleton method in the receiver. The method parameter can be a Proc, a Method or an UnboundMethod object. If a block is specified, it is used as the method body. If a block or a method has parameters, they’re used as method parameters.

Example

class A
  class << self
    def class_name
      to_s
    end
  end
end
A.define_singleton_method(:who_am_i) do
  "I am: #{class_name}"
end
A.who_am_i   # ==> "I am: A"

guy = "Bob"
guy.define_singleton_method(:hello) { "#{self}: Hello there!" }
guy.hello    #=>  "Bob: Hello there!"

chris = "Chris"
chris.define_singleton_method(:greet) {|greeting| "#{greeting}, I'm Chris!" }
chris.greet("Hi") #=> "Hi, I'm Chris!"

See also #=== #DelegateClass #<=> #Digest also in 4.1 · 3.4 · 3.3 · 3.2 · 3.1 · 3.0

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