225

$0 is the variable for the top level Ruby program, but is there one for the current method?

the Tin Man
  • 158,662
  • 42
  • 215
  • 303
salt.racer
  • 21,903
  • 14
  • 44
  • 51
  • One use is checking `super` can be called within a SimpleDelegator object: `def description; __getobj__.respond_to?(__method__) ? super : 'No description'; end` – Kris Sep 26 '13 at 13:57

5 Answers5

381

Even better than my first answer you can use __method__:

class Foo
  def test_method
    __method__
  end
end

This returns a symbol – for example, :test_method. To return the method name as a string, call __method__.to_s instead.

Note: This requires Ruby 1.8.7.

Joshua Pinter
  • 45,245
  • 23
  • 243
  • 245
Mark A. Nicolosi
  • 82,413
  • 11
  • 44
  • 46
35

Depending on what you actually want, you can use either __method__ or __callee__, which return the currently executing method's name as a symbol.

On ruby 1.9, both of them behave identically (as far as the docs and my testing are concerned).

On ruby 2.1 & 2.2 __callee__ behaves differently if you call an alias of the defined method. The docs for the two are different:

  • __method__: "the name at the definition of the current method" (i.e. the name as it was defined)
  • __callee__: "the called name of the current method" (i.e. the name as it was called (invoked))

Test script:

require 'pp'
puts RUBY_VERSION
class Foo
  def orig
    {callee: __callee__, method: __method__}
  end
  alias_method :myalias, :orig
end
pp( {call_orig: Foo.new.orig, call_alias: Foo.new.myalias} )

1.9.3 Output:

1.9.3
{:call_orig=>{:callee=>:orig, :method=>:orig},
 :call_alias=>{:callee=>:orig, :method=>:orig}}

2.1.2 Output (__callee__ returns the aliased name, but __method__ returns the name at the point the method was defined):

2.1.2
{:call_orig=>{:callee=>:orig, :method=>:orig},
 :call_alias=>{:callee=>:myalias, :method=>:orig}}
Kelvin
  • 20,119
  • 3
  • 60
  • 68
28

From http://snippets.dzone.com/posts/show/2785:

module Kernel
private
    def this_method_name
      caller[0] =~ /`([^']*)'/ and $1
    end
end

class Foo
  def test_method
    this_method_name
  end
end

puts Foo.new.test_method    # => test_method
Mark A. Nicolosi
  • 82,413
  • 11
  • 44
  • 46
12

For Ruby 1.9+ I'd recommend using __callee__

l3x
  • 30,760
  • 1
  • 55
  • 36
  • 3
    `__callee__` behaves differently prior to 1.9, so it's best to stick with `__method__` since it has consistent behavior. `__callee__` behaves the same as `__method__` after 1.9. – Leigh McCulloch Apr 09 '14 at 03:25
  • @LeighMcCulloch can you explain the difference with an example (possibly in a new answer)? – Ciro Santilli OurBigBook.com Sep 11 '14 at 08:11
  • 1
    @CiroSantilli六四事件法轮功纳米比亚威视 `def m1() puts("here is #{__method__} method. My caller is #{__callee__}.") end; def m2() puts("here is #{__method__} method. Let's call m1"); m1 end; m2` Don't you see anything strange ? – jgburet Jul 08 '15 at 11:20
  • 4
    @LeighMcCulloch actually now `__callee__` and `__method__` has different behaviour. See http://pastie.org/10380985 (ruby 2.1.5) – goodniceweb Aug 28 '15 at 08:26
  • 1
    pastie.org is down. Forever or just now? – Nakilon Mar 18 '18 at 02:12
  • In Ruby 2.6, I have an aliased method: `__method__` returned me the name of the real method (the one filled with code), `__callee__` returned the alias used. – Rael Gugelmin Cunha May 28 '21 at 18:02
-3

I got the same issue to retrieve method name in view file. I got the solution by

params[:action] # it will return method's name

if you want to get controller's name then

params[:controller] # it will return you controller's name
Hetal Khunti
  • 787
  • 1
  • 9
  • 23