# from http://www.nobugs.org/developer/ruby/method_finder.html

class Object
  # Clone fails on numbers, but they're immutable anyway
  def megaClone
    begin self.clone; rescue; self; end
  end
end

class MethodFinder

  # Find all methods on [anObject] which, when called with [args] return [expectedResult]
  def self.find( anObject, expectedResult, *args )
    anObject.methods.select { |name| anObject.method(name).arity == args.size }.
                     select { |name| begin anObject.megaClone.method( name ).call(*args) == expectedResult; 
                                     rescue; end }
  end

  # Pretty-prints the results of the previous method
  def self.show( anObject, expectedResult, *args )
    find( anObject, expectedResult, *args ).each { |name|
      print "#{anObject.inspect}.#{name}" 
      print "(" + args.map { |o| o.inspect }.join(", ") + ")" unless args.empty?
      puts " == #{expectedResult.inspect}" 
    }
  end
end

# Look for string length method; ie. something which returns 5 when called on "hello"
MethodFinder.show( "hello", 5 )

# Look for string concatenation
MethodFinder.show( "foo", "foobar", "bar" )

# Look for floor function
MethodFinder.show( 3.14159, 3 )