From a180b007d96fe68b32f11dec720fbd0cd5b6758a Mon Sep 17 00:00:00 2001 From: Serhiy Storchaka Date: Mon, 25 Feb 2019 17:58:30 +0200 Subject: bpo-28450: Fix and improve the documentation for unknown escapes in RE. (GH-11920) --- Doc/library/re.rst | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/Doc/library/re.rst b/Doc/library/re.rst index b512830..4ac5dee 100644 --- a/Doc/library/re.rst +++ b/Doc/library/re.rst @@ -573,7 +573,8 @@ accepted by the regular expression parser:: only inside character classes.) ``'\u'``, ``'\U'``, and ``'\N'`` escape sequences are only recognized in Unicode -patterns. In bytes patterns they are errors. +patterns. In bytes patterns they are errors. Unknown escapes of ASCII +letters are reserved for future use and treated as errors. Octal escapes are included in a limited form. If the first digit is a 0, or if there are three octal digits, it is considered an octal escape. Otherwise, it is @@ -850,7 +851,9 @@ form. *string* is returned unchanged. *repl* can be a string or a function; if it is a string, any backslash escapes in it are processed. That is, ``\n`` is converted to a single newline character, ``\r`` is converted to a carriage return, and - so forth. Unknown escapes such as ``\&`` are left alone. Backreferences, such + so forth. Unknown escapes of ASCII letters are reserved for future use and + treated as errors. Other unknown escapes such as ``\&`` are left alone. + Backreferences, such as ``\6``, are replaced with the substring matched by group 6 in the pattern. For example:: -- cgit v0.12