From 88c8a523a7653a80d5f2f88b33e9d455a42402b7 Mon Sep 17 00:00:00 2001 From: Paul Tremberth Date: Wed, 15 Jan 2014 12:52:10 +0100 Subject: [PATCH] Add warning in docs on performance when using EXSLT regexp functions --- docs/topics/selectors.rst | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/docs/topics/selectors.rst b/docs/topics/selectors.rst index deff0d8dc..af48a1b07 100644 --- a/docs/topics/selectors.rst +++ b/docs/topics/selectors.rst @@ -280,7 +280,10 @@ Example selecting links in list item with a "class" attribute ending with a digi [u'link1.html', u'link2.html', u'link4.html', u'link5.html'] >>> - +.. warning:: C library ``libxslt`` doesn't natively support EXSLT regular + expressions so `lxml`_'s implementation uses hooks to Python's ``re`` module. + Thus, using regexp functions in your XPath expressions may add a small + performance penalty. Set operations ~~~~~~~~~~~~~~