PG 18+

puby.rb

require 'ffi'

module Puby
  module Python
    extend FFI::Library
    ffi_lib ['python2.7']

    SINGLE_INPUT = 256
    FILE_INPUT   = 257
    EVAL_INPUT   = 258

    attach_function :initialize, :Py_Initialize, [], :void
    attach_function :finalize, :Py_Finalize, [], :void

    attach_function :run_simple_string, :PyRun_SimpleString, [:string], :void

    attach_function :python_string_from_string,
      :PyString_FromString,
      [:string],
      :pointer

    attach_function :python_string_as_string,
      :PyString_AsString,
      [:pointer],
      :string

    attach_function :run_string,
      :PyRun_String,
      [:string, :int, :pointer, :pointer],
      :pointer

    attach_function :run_file,
      :PyRun_File,
      [:pointer, :string, :int, :pointer, :pointer],
      :pointer

    attach_function :import_add_module,
      :PyImport_AddModule,
      [:string],
      :pointer

    attach_function :module_get_dict,
      :PyModule_GetDict,
      [:pointer],
      :pointer

    attach_function :object_get_attr_string,
      :PyObject_GetAttrString,
      [:pointer, :string],
      :pointer

    attach_function :object_call_object,
      :PyObject_CallObject,
      [:pointer, :pointer],
      :pointer

    attach_function :tuple_new, :PyTuple_New, [:int], :pointer

    attach_function :increment_ref, :Py_IncRef, [:pointer], :void
    attach_function :decrement_ref, :Py_DecRef, [:pointer], :void
  end # Python
end # Puby

Puby::Python.initialize

main_module = Puby::Python.import_add_module('__main__')
main_dict   = Puby::Python.module_get_dict(main_module)

code = <<-EOF
def testing():
  return "Hello"
EOF

result = Puby::Python.run_string(code, Puby::Python::FILE_INPUT, main_dict, main_dict)

Puby::Python.decrement_ref(result)

method = Puby::Python.object_get_attr_string(main_module, "testing")
args   = Puby::Python.tuple_new(0)
retval = Puby::Python.object_call_object(method, args)
string = Puby::Python.python_string_as_string(retval)

puts string

Puby::Python.decrement_ref(args)
Puby::Python.decrement_ref(retval)
Puby::Python.decrement_ref(method)
Puby::Python.decrement_ref(main_dict)

Puby::Python.finalize