setup.py 文件源码

def __getitem__(self, key):
        if key != 'build_ext':
            return super(LazyBuildExtCommandClass, self).__getitem__(key)

        from Cython.Distutils import build_ext as cython_build_ext
        import numpy

        # Cython_build_ext isn't a new-style class in Py2.
        class build_ext(cython_build_ext, object):
            """
            Custom build_ext command that lazily adds numpy's include_dir to
            extensions.
            """

            def build_extensions(self):
                """
                Lazily append numpy's include directory to Extension includes.

                This is done here rather than at module scope because setup.py
                may be run before numpy has been installed, in which case
                importing numpy and calling `numpy.get_include()` will fail.
                """
                numpy_incl = numpy.get_include()
                for ext in self.extensions:
                    ext.include_dirs.append(numpy_incl)

                super(build_ext, self).build_extensions()

        return build_ext