def isinteger(x):
try:
return int(x) == x
except (TypeError, ValueError):
return False
# === Legacy Version Support ===
# :pyver:old: PyPNG works on Python versions 2.3 and 2.2, but not
# without some awkward problems. Really PyPNG works on Python 2.4 (and
# above); it works on Pythons 2.3 and 2.2 by virtue of fixing up
# problems here. It's a bit ugly (which is why it's hidden down here).
#
# Generally the strategy is one of pretending that we're running on
# Python 2.4 (or above), and patching up the library support on earlier
# versions so that it looks enough like Python 2.4. When it comes to
# Python 2.2 there is one thing we cannot patch: extended slices
# http://www.python.org/doc/2.3/whatsnew/section-slices.html.
# Instead we simply declare that features that are implemented using
# extended slices will not work on Python 2.2.
#
# In order to work on Python 2.3 we fix up a recurring annoyance involving
# the array type. In Python 2.3 an array cannot be initialised with an
# array, and it cannot be extended with a list (or other sequence).
# Both of those are repeated issues in the code. Whilst I would not
# normally tolerate this sort of behaviour, here we "shim" a replacement
# for array into place (and hope no-one notices). You never read this.
#
# In an amusing case of warty hacks on top of warty hacks... the array
# shimming we try and do only works on Python 2.3 and above (you can't
# subclass array.array in Python 2.2). So to get it working on Python
# 2.2 we go for something much simpler and (probably) way slower.
评论列表
文章目录
