python-astropy/astropy-ply.py
2017-10-09 17:42:16 +02:00

59 lines
1.6 KiB
Python

# Licensed under a 3-clause BSD style license - see LICENSE.rst
"""
Handle loading ply package from system or from the bundled copy
"""
import imp
from distutils.version import StrictVersion
def _find_module(name, path=None):
"""
Alternative to `imp.find_module` that can also search in subpackages.
"""
parts = name.split('.')
for part in parts:
if path is not None:
path = [path]
fh, path, descr = imp.find_module(part, path)
return fh, path, descr
_PLY_MIN_VERSION = StrictVersion('3.9')
# Update this to prevent Astropy from using its bundled copy of ply
# (but only if some other version of at least _PLY_MIN_VERSION can
# be provided)
_PLY_SEARCH_PATH = ['ply']
for mod_name in _PLY_SEARCH_PATH:
try:
mod_info = _find_module(mod_name)
#mod_lex_info = _find_module(mod_name + '.lex')
except ImportError:
continue
mod = imp.load_module(__name__, *mod_info)
#mod_lex = imp.load_module(__name__ + '.lex', *mod_lex_info)
try:
# if StrictVersion(mod_lex.__version__) >= _PLY_MIN_VERSION:
# break
break
except (AttributeError, ValueError):
# Attribute error if the ply module isn't what it should be and doesn't
# have a .__version__; ValueError if the version string exists but is
# somehow bogus/unparseable
continue
else:
raise ImportError(
"Astropy requires the 'ply' module of minimum version {0}; "
"normally this is bundled with the astropy package so if you get "
"this warning consult the packager of your Astropy "
"distribution.".format(_PLY_MIN_VERSION))