requirements-optional.txt

-r requirements.txt

# We support a Genshi treewalker that can be used to serialize Genshi
# streams.
genshi

# chardet can be used as a fallback in case we are unable to determine
# the encoding of a document.
chardet>=2.2

# lxml is supported with its own treebuilder ("lxml") and otherwise
# uses the standard ElementTree support
lxml ; platform_python_implementation == 'CPython'

# DATrie can be used in place of our Python trie implementation for
# slightly better parsing performance.
# https://github.com/pytries/datrie/issues/52 although closed is not
# yet released to https://pypi.org/project/datrie
datrie ; platform_python_implementation == 'CPython' and python_version < '3.7'