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authorEzio Melotti <ezio.melotti@gmail.com>2011-10-20 16:45:39 (GMT)
committerEzio Melotti <ezio.melotti@gmail.com>2011-10-20 16:45:39 (GMT)
commit9927e0ce351f7eb0157d13ba6cc8978d3e594948 (patch)
treeacac80bc0ff200e90c7942e0c234714c725b2fac
parentd11a64d54cdf51537a2c8936b6585f65b3007792 (diff)
parent27607290a63f8851a261b8c707b9b2d5b75a84eb (diff)
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Merge heads.
-rw-r--r--Doc/library/re.rst54
1 files changed, 30 insertions, 24 deletions
diff --git a/Doc/library/re.rst b/Doc/library/re.rst
index 2c150cc..331ffa7 100644
--- a/Doc/library/re.rst
+++ b/Doc/library/re.rst
@@ -161,30 +161,36 @@ The special characters are:
raw strings for all but the simplest expressions.
``[]``
- Used to indicate a set of characters. Characters can be listed individually, or
- a range of characters can be indicated by giving two characters and separating
- them by a ``'-'``. Special characters are not active inside sets. For example,
- ``[akm$]`` will match any of the characters ``'a'``, ``'k'``,
- ``'m'``, or ``'$'``; ``[a-z]`` will match any lowercase letter, and
- ``[a-zA-Z0-9]`` matches any letter or digit. Character classes such
- as ``\w`` or ``\S`` (defined below) are also acceptable inside a
- range, although the characters they match depends on whether
- :const:`ASCII` or :const:`LOCALE` mode is in force. If you want to
- include a ``']'`` or a ``'-'`` inside a set, precede it with a
- backslash, or place it as the first character. The pattern ``[]]``
- will match ``']'``, for example.
-
- You can match the characters not within a range by :dfn:`complementing` the set.
- This is indicated by including a ``'^'`` as the first character of the set;
- ``'^'`` elsewhere will simply match the ``'^'`` character. For example,
- ``[^5]`` will match any character except ``'5'``, and ``[^^]`` will match any
- character except ``'^'``.
-
- Note that inside ``[]`` the special forms and special characters lose
- their meanings and only the syntaxes described here are valid. For
- example, ``+``, ``*``, ``(``, ``)``, and so on are treated as
- literals inside ``[]``, and backreferences cannot be used inside
- ``[]``.
+ Used to indicate a set of characters. In a set:
+
+ * Characters can be listed individually, e.g. ``[amk]`` will match ``'a'``,
+ ``'m'``, or ``'k'``.
+
+ * Ranges of characters can be indicated by giving two characters and separating
+ them by a ``'-'``, for example ``[a-z]`` will match any lowercase ASCII letter,
+ ``[0-5][0-9]`` will match all the two-digits numbers from ``00`` to ``59``, and
+ ``[0-9A-Fa-f]`` will match any hexadecimal digit. If ``-`` is escaped (e.g.
+ ``[a\-z]``) or if it's placed as the first or last character (e.g. ``[a-]``),
+ it will match a literal ``'-'``.
+
+ * Special characters lose their special meaning inside sets. For example,
+ ``[(+*)]`` will match any of the literal characters ``'('``, ``'+'``,
+ ``'*'``, or ``')'``.
+
+ * Character classes such as ``\w`` or ``\S`` (defined below) are also accepted
+ inside a set, although the characters they match depends on whether
+ :const:`ASCII` or :const:`LOCALE` mode is in force.
+
+ * Characters that are not within a range can be matched by :dfn:`complementing`
+ the set. If the first character of the set is ``'^'``, all the characters
+ that are *not* in the set will be matched. For example, ``[^5]`` will match
+ any character except ``'5'``, and ``[^^]`` will match any character except
+ ``'^'``. ``^`` has no special meaning if it's not the first character in
+ the set.
+
+ * To match a literal ``']'`` inside a set, precede it with a backslash, or
+ place it at the beginning of the set. For example, both ``[()[\]{}]`` and
+ ``[]()[{}]`` will both match a parenthesis.
``'|'``
``A|B``, where A and B can be arbitrary REs, creates a regular expression that