gem 'pybind'

# This program prints Hello, world!
require 'pybind'

# You can eval a string in Python with `PyBind.eval`,
# this is the easiest way to use PyBind.rb
# and this is equivalent to Python built-in `eval` function
PyBind.eval('print("Hello, world!")')

# Or exec a Python file
PyBind.execfile('examples/hello_world.py')

# You can find all Python built-in functions at `PyBind.builtin`
# Note that `PyBind.builtin.print` is a Python function object,
# like a `proc` in Ruby, you need to call it by adding a `.` or `.call`
# if you don't like it, see `pybind/autocall` secion below
PyBind.builtin.print.('hello, world!')

require 'pybind'

os = PyBind.import('os')
puts os.name

# or more python-like
require 'pybind'
include PyBind::Import

pyimport 'os'
puts os.name

require 'pybind'

Fraction = PyBind.import('fractions').Fraction

class PyFraction
  include PyBind::PyObjectWrapper
  pybind_type Fraction
end

f = Fraction.(1, 2)
f.kind_of? PyFraction # => true
f.numerator # => 1
f.denominator # => 2

require 'pybind'

class Rational
  include PyBind::PyObjectWrapper

  Fraction = PyBind.import('fractions').Fraction

  pybind_type Fraction do |pystruct|
    # pystruct is a PyObjectStruct, which is a FFI::Struct
    # This block defines how Python object converts to Ruby object
    # By default, it's `new(pystruct)`

    # For easily access the attributes, let's convert it to PyObject
    pyobj = pystruct.to_ruby_object
    new(pyobj.numerator, pyobj.denominator)
  end

  def to_python
    # This block defines how Ruby object converts back to Python object
    Fraction.(self.numerator, self.denominator)
  end
end

require 'pybind'
require 'pybind/autocall'

# No dot anymore, if you need the function object, you need to call
# `PyBind.builtin.get_attribute(:print)`
PyBind.builtin.print('Hello, world!')