docs: Add skeleton docs for ure module.

docs/library/index.rst

@@ -42,6 +42,7 @@ it will fallback to loading the built-in ``ujson`` module.
    uhashlib.rst
    uheapq.rst
    ujson.rst
+   ure.rst
    usocket.rst
 
 Libraries specific to the pyboard

docs/library/ure.rst

@@ -0,0 +1,82 @@
+:mod:`ure` -- regular expressions
+=================================
+
+.. module:: ure
+   :synopsis: regular expressions
+
+This module implements regular expression operations. Regular expression
+syntax supported is a subset of CPython ``re`` module (and actually is
+a subset of POSIX extended regular expressions).
+
+Supported operators are:
+
+``'.'``
+   Match any character.
+
+``'[]'``
+   Match set of characters. Individual characters and ranges are supported.
+
+``'^'``
+
+``'$'``
+
+``'?'``
+
+``'*'``
+
+``'+'``
+
+``'??'``
+
+``'*?'``
+
+``'+?'``
+
+Counted repetitions (``{m,n}``), more advanced assertions, names groups,
+etc. are not supported.
+
+
+Functions
+---------
+
+.. function:: compile(regex)
+
+   Compile regular expression, return ``regex`` object.
+
+.. function:: match(regex, string)
+
+   Match ``regex`` against ``string``. Match always happens from starting
+   position in a string.
+
+.. function:: search(regex, string)
+
+   Search ``regex`` in a ``string``. Unlike ``match``, this will search
+   string for first position which matches regex (which still may be
+   0 if regex is anchored).
+
+.. data:: DEBUG
+
+   Flag value, display debug information about compiled expression.
+
+
+Regex objects
+-------------
+
+Compiled regular expression. Instances of this class are created using
+``ure.compile()``.
+
+.. method:: regex.match(string)
+
+.. method:: regex.search(string)
+
+.. method:: regex.split(string, max_split=-1)
+
+
+Match objects
+-------------
+
+Match objects as returned by ``match()`` and ``search()`` methods.
+
+.. method:: match.group([index])
+
+   Only numeric groups are supported.