#
#Python script interpreter
#
#Build from sources and install where find_package(python) will find it.
#We build libpython as a shared library so that other host tools can use it.
#For example, various neural network frameworks like Caffe and TensorFlow
#want to link with Python to provide a scripting language for training neural
#networks.
#

if (WIN32)
ExternalProject_Add (
  python3
  PREFIX ${CMAKE_INSTALL_PREFIX}
  URL https://github.com/python-cmake-buildsystem/python-cmake-buildsystem/archive/cc93717837469bcd36746b91739949f100e64123.zip
  URL_MD5 e77917ab0d2f6bc45326611dc7c8c288
  PATCH_COMMAND ${CMAKE_COMMAND} -E copy_directory ${CMAKE_CURRENT_LIST_DIR}/patch .
  CMAKE_ARGS -DCMAKE_INSTALL_PREFIX:PATH=<INSTALL_DIR>
     -DPYTHON_VERSION:STRING=3.5.2
     -DCMAKE_BUILD_TYPE:STRING=Release
     -DBUILD_LIBPYTHON_SHARED:BOOL=ON
     -DINSTALL_WINDOWS_TRADITIONAL:BOOL=OFF
     -DBUILD_WININST:BOOL=OFF
     -DBUILD_WININST_ALWAYS:BOOL=OFF
     -DINSTALL_MANUAL:BOOL=OFF
     -DINSTALL_TEST:BOOL=OFF
)
endif (WIN32)

if (UNIX)
#Rely on manual installation via the package manager
#You can then invoke python as /usr/bin/python3
#sudo apt-get install python3
ExternalProject_Add (
  python3
  PREFIX ${CMAKE_INSTALL_PREFIX}
  BUILD_IN_SOURCE 1
  DOWNLOAD_COMMAND ""
  UPDATE_COMMAND ""
  CONFIGURE_COMMAND ""
  BUILD_COMMAND /usr/bin/python3 --version
  INSTALL_COMMAND ""
)
endif (UNIX)