.. productionlist::
stringliteral: [`stringprefix`](`shortstring` | `longstring`)
- stringprefix: "r" | "u" | "ur" | "R" | "U" | "UR" | "Ur" | "uR"
+ stringprefix: "r" | "u" | "R" | "U"
shortstring: "'" `shortstringitem`* "'" | '"' `shortstringitem`* '"'
longstring: "'''" `longstringitem`* "'''" | '"""' `longstringitem`* '"""'
shortstringitem: `shortstringchar` | `stringescapeseq`
As of Python 3.3 it is possible again to prefix unicode strings with a
``u`` prefix to simplify maintenance of dual 2.x and 3.x codebases.
-Both string and bytes literals may optionally be prefixed with a letter ``'r'``
+Bytes literals may optionally be prefixed with a letter ``'r'``
or ``'R'``; such strings are called :dfn:`raw strings` and treat backslashes as
literal characters. As a result, in string literals, ``'\U'`` and ``'\u'``
-escapes in raw strings are not treated specially.
+escapes in raw strings are not treated specially. Given that Python 2.x's raw
+unicode literals behave differently than Python 3.x's the ``'ur'`` syntax
+is not supported.
.. versionadded:: 3.3
The ``'rb'`` prefix of raw bytes literals has been added as a synonym
of ``'br'``.
.. versionadded:: 3.3
- Support for the unicode legacy literal (``u'value'``) and other
- versions were reintroduced to simplify the maintenance of dual
- Python 2.x and 3.x codebases. See :pep:`414` for more information.
+ Support for the unicode legacy literal (``u'value'``) was reintroduced
+ to simplify the maintenance of dual Python 2.x and 3.x codebases.
+ See :pep:`414` for more information.
In triple-quoted strings, unescaped newlines and quotes are allowed (and are
retained), except that three unescaped quotes in a row terminate the string. (A
self.assertRaises(SyntaxError, eval, """ rrb'' """)
self.assertRaises(SyntaxError, eval, """ rbb'' """)
+ def test_eval_str_u(self):
+ self.assertEqual(eval(""" u'x' """), 'x')
+ self.assertEqual(eval(""" U'\u00e4' """), 'ä')
+ self.assertEqual(eval(""" u'\N{LATIN SMALL LETTER A WITH DIAERESIS}' """), 'ä')
+ self.assertRaises(SyntaxError, eval, """ ur'' """)
+ self.assertRaises(SyntaxError, eval, """ ru'' """)
+ self.assertRaises(SyntaxError, eval, """ bu'' """)
+ self.assertRaises(SyntaxError, eval, """ ub'' """)
+
def check_encoding(self, encoding, extra=""):
modname = "xx_" + encoding.replace("-", "_")
fn = os.path.join(self.tmpdir, modname + ".py")
STRING 'u"abc"' (1, 0) (1, 6)
OP '+' (1, 7) (1, 8)
STRING 'U"abc"' (1, 9) (1, 15)
- >>> dump_tokens("ur'abc' + uR'abc' + Ur'abc' + UR'abc'")
- ENCODING 'utf-8' (0, 0) (0, 0)
- STRING "ur'abc'" (1, 0) (1, 7)
- OP '+' (1, 8) (1, 9)
- STRING "uR'abc'" (1, 10) (1, 17)
- OP '+' (1, 18) (1, 19)
- STRING "Ur'abc'" (1, 20) (1, 27)
- OP '+' (1, 28) (1, 29)
- STRING "UR'abc'" (1, 30) (1, 37)
- >>> dump_tokens('ur"abc" + uR"abc" + Ur"abc" + UR"abc"')
- ENCODING 'utf-8' (0, 0) (0, 0)
- STRING 'ur"abc"' (1, 0) (1, 7)
- OP '+' (1, 8) (1, 9)
- STRING 'uR"abc"' (1, 10) (1, 17)
- OP '+' (1, 18) (1, 19)
- STRING 'Ur"abc"' (1, 20) (1, 27)
- OP '+' (1, 28) (1, 29)
- STRING 'UR"abc"' (1, 30) (1, 37)
>>> dump_tokens("b'abc' + B'abc'")
ENCODING 'utf-8' (0, 0) (0, 0)
Legacy unicode literals:
- >>> dump_tokens("Örter = u'places'\\ngrün = UR'green'")
+ >>> dump_tokens("Örter = u'places'\\ngrün = U'green'")
ENCODING 'utf-8' (0, 0) (0, 0)
NAME 'Örter' (1, 0) (1, 5)
OP '=' (1, 6) (1, 7)
NEWLINE '\\n' (1, 17) (1, 18)
NAME 'grün' (2, 0) (2, 4)
OP '=' (2, 5) (2, 6)
- STRING "UR'green'" (2, 7) (2, 16)
+ STRING "U'green'" (2, 7) (2, 15)
"""
from test import support
Imagnumber = group(r'[0-9]+[jJ]', Floatnumber + r'[jJ]')
Number = group(Imagnumber, Floatnumber, Intnumber)
-StringPrefix = r'(?:[uUbB][rR]?|[rR][bB]?)?'
+StringPrefix = r'(?:[bB][rR]?|[rR][bB]?|[uU])?'
# Tail end of ' string.
Single = r"[^'\\]*(?:\\.[^'\\]*)*'"
"rB'''": Single3, 'rB"""': Double3,
"RB'''": Single3, 'RB"""': Double3,
"u'''": Single3, 'u"""': Double3,
- "ur'''": Single3, 'ur"""': Double3,
"R'''": Single3, 'R"""': Double3,
"U'''": Single3, 'U"""': Double3,
- "uR'''": Single3, 'uR"""': Double3,
- "Ur'''": Single3, 'Ur"""': Double3,
- "UR'''": Single3, 'UR"""': Double3,
'r': None, 'R': None, 'b': None, 'B': None,
'u': None, 'U': None}
"rb'''", 'rb"""', "rB'''", 'rB"""',
"Rb'''", 'Rb"""', "RB'''", 'RB"""',
"u'''", 'u"""', "U'''", 'U"""',
- "ur'''", 'ur"""', "Ur'''", 'Ur"""',
- "uR'''", 'uR"""', "UR'''", 'UR"""'):
+ ):
triple_quoted[t] = t
single_quoted = {}
for t in ("'", '"',
"rb'", 'rb"', "rB'", 'rB"',
"Rb'", 'Rb"', "RB'", 'RB"' ,
"u'", 'u"', "U'", 'U"',
- "ur'", 'ur"', "Ur'", 'Ur"',
- "uR'", 'uR"', "UR'", 'UR"' ):
+ ):
single_quoted[t] = t
tabsize = 8
Core and Builtins
-----------------
+- Issue #15096: Removed support for ur'' as the raw notation isn't
+ compatible with Python 2.x's raw unicode strings.
+
- Issue #13783: Generator objects now use the identifier APIs internally
- Issue #14874: Restore charmap decoding speed to pre-PEP 393 levels.
/* Identifier (most frequent token!) */
nonascii = 0;
if (is_potential_identifier_start(c)) {
- /* Process b"", r"", u"", br"", rb"" and ur"" */
+ /* Process b"", r"", u"", br"" and rb"" */
int saw_b = 0, saw_r = 0, saw_u = 0;
while (1) {
if (!(saw_b || saw_u) && (c == 'b' || c == 'B'))
want to support it in arbitrary order like byte literals. */
else if (!(saw_b || saw_u || saw_r) && (c == 'u' || c == 'U'))
saw_u = 1;
- else if (!saw_r && (c == 'r' || c == 'R'))
+ /* ur"" and ru"" are not supported */
+ else if (!(saw_r || saw_u) && (c == 'r' || c == 'R'))
saw_r = 1;
else
break;
projects / python / commitdiff