int foo(int x) int a = 5 return a end 3.foo( 4 ) -- -- -- s(:expressions, s(:function, :int, s(:name, :foo), s(:parameters, s(:parameter, :int, :x)), s(:expressions, s(:field_def, :int, :a, s(:int, 5)), s(:return, s(:name, :a)))), s(:call, s(:name, :foo), s(:arguments, s(:int, 4)), s(:receiver, s(:int, 3))))