RustPython
diff --git a/‎Lib/re.py‎ ‎Lib/re/__init__.py‎Lib/re.py renamed to Lib/re/__init__.py
Lines changed: 132 additions & 89 deletions b/‎Lib/re.py‎ ‎Lib/re/__init__.py‎Lib/re.py renamed to Lib/re/__init__.py
Lines changed: 132 additions & 89 deletions
@@ -122,65 +122,40 @@
 """
 
 import enum
-import sre_compile
-import sre_parse
+from . import _compiler, _parser
 import functools
-try:
-    import _locale
-except ImportError:
-    _locale = None
+import _sre
 
 
 # public symbols
 __all__ = [
     "match", "fullmatch", "search", "sub", "subn", "split",
-    "findall", "finditer", "compile", "purge", "template", "escape",
+    "findall", "finditer", "compile", "purge", "escape",
     "error", "Pattern", "Match", "A", "I", "L", "M", "S", "X", "U",
     "ASCII", "IGNORECASE", "LOCALE", "MULTILINE", "DOTALL", "VERBOSE",
-    "UNICODE",
+    "UNICODE", "NOFLAG", "RegexFlag",
 ]
 
 __version__ = "2.2.1"
 
-class RegexFlag(enum.IntFlag):
-    ASCII = A = sre_compile.SRE_FLAG_ASCII # assume ascii "locale"
-    IGNORECASE = I = sre_compile.SRE_FLAG_IGNORECASE # ignore case
-    LOCALE = L = sre_compile.SRE_FLAG_LOCALE # assume current 8-bit locale
-    UNICODE = U = sre_compile.SRE_FLAG_UNICODE # assume unicode "locale"
-    MULTILINE = M = sre_compile.SRE_FLAG_MULTILINE # make anchors look for newline
-    DOTALL = S = sre_compile.SRE_FLAG_DOTALL # make dot match newline
-    VERBOSE = X = sre_compile.SRE_FLAG_VERBOSE # ignore whitespace and comments
+@enum.global_enum
+@enum._simple_enum(enum.IntFlag, boundary=enum.KEEP)
+class RegexFlag:
+    NOFLAG = 0
+    ASCII = A = _compiler.SRE_FLAG_ASCII # assume ascii "locale"
+    IGNORECASE = I = _compiler.SRE_FLAG_IGNORECASE # ignore case
+    LOCALE = L = _compiler.SRE_FLAG_LOCALE # assume current 8-bit locale
+    UNICODE = U = _compiler.SRE_FLAG_UNICODE # assume unicode "locale"
+    MULTILINE = M = _compiler.SRE_FLAG_MULTILINE # make anchors look for newline
+    DOTALL = S = _compiler.SRE_FLAG_DOTALL # make dot match newline
+    VERBOSE = X = _compiler.SRE_FLAG_VERBOSE # ignore whitespace and comments
     # sre extensions (experimental, don't rely on these)
-    TEMPLATE = T = sre_compile.SRE_FLAG_TEMPLATE # disable backtracking
-    DEBUG = sre_compile.SRE_FLAG_DEBUG # dump pattern after compilation
-
-    def __repr__(self):
-        if self._name_ is not None:
-            return f're.{self._name_}'
-        value = self._value_
-        members = []
-        negative = value < 0
-        if negative:
-            value = ~value
-        for m in self.__class__:
-            if value & m._value_:
-                value &= ~m._value_
-                members.append(f're.{m._name_}')
-        if value:
-            members.append(hex(value))
-        res = '|'.join(members)
-        if negative:
-            if len(members) > 1:
-                res = f'~({res})'
-            else:
-                res = f'~{res}'
-        return res
+    DEBUG = _compiler.SRE_FLAG_DEBUG # dump pattern after compilation
     __str__ = object.__str__
-
-globals().update(RegexFlag.__members__)
+    _numeric_repr_ = hex
 
 # sre exception
-error = sre_compile.error
+error = _compiler.error
 
 # --------------------------------------------------------------------
 # public interface
@@ -200,16 +175,39 @@ def search(pattern, string, flags=0):
     a Match object, or None if no match was found."""
     return _compile(pattern, flags).search(string)
 
-def sub(pattern, repl, string, count=0, flags=0):
+class _ZeroSentinel(int):
+    pass
+_zero_sentinel = _ZeroSentinel()
+
+def sub(pattern, repl, string, *args, count=_zero_sentinel, flags=_zero_sentinel):
     """Return the string obtained by replacing the leftmost
     non-overlapping occurrences of the pattern in string by the
     replacement repl.  repl can be either a string or a callable;
     if a string, backslash escapes in it are processed.  If it is
     a callable, it's passed the Match object and must return
     a replacement string to be used."""
+    if args:
+        if count is not _zero_sentinel:
+            raise TypeError("sub() got multiple values for argument 'count'")
+        count, *args = args
+        if args:
+            if flags is not _zero_sentinel:
+                raise TypeError("sub() got multiple values for argument 'flags'")
+            flags, *args = args
+            if args:
+                raise TypeError("sub() takes from 3 to 5 positional arguments "
+                                "but %d were given" % (5 + len(args)))
+
+        import warnings
+        warnings.warn(
+            "'count' is passed as positional argument",
+            DeprecationWarning, stacklevel=2
+        )
+
     return _compile(pattern, flags).sub(repl, string, count)
+sub.__text_signature__ = '(pattern, repl, string, count=0, flags=0)'
 
-def subn(pattern, repl, string, count=0, flags=0):
+def subn(pattern, repl, string, *args, count=_zero_sentinel, flags=_zero_sentinel):
     """Return a 2-tuple containing (new_string, number).
     new_string is the string obtained by replacing the leftmost
     non-overlapping occurrences of the pattern in the source
@@ -218,17 +216,55 @@ def subn(pattern, repl, string, count=0, flags=0):
     callable; if a string, backslash escapes in it are processed.
     If it is a callable, it's passed the Match object and must
     return a replacement string to be used."""
+    if args:
+        if count is not _zero_sentinel:
+            raise TypeError("subn() got multiple values for argument 'count'")
+        count, *args = args
+        if args:
+            if flags is not _zero_sentinel:
+                raise TypeError("subn() got multiple values for argument 'flags'")
+            flags, *args = args
+            if args:
+                raise TypeError("subn() takes from 3 to 5 positional arguments "
+                                "but %d were given" % (5 + len(args)))
+
+        import warnings
+        warnings.warn(
+            "'count' is passed as positional argument",
+            DeprecationWarning, stacklevel=2
+        )
+
     return _compile(pattern, flags).subn(repl, string, count)
+subn.__text_signature__ = '(pattern, repl, string, count=0, flags=0)'
 
-def split(pattern, string, maxsplit=0, flags=0):
+def split(pattern, string, *args, maxsplit=_zero_sentinel, flags=_zero_sentinel):
     """Split the source string by the occurrences of the pattern,
     returning a list containing the resulting substrings.  If
     capturing parentheses are used in pattern, then the text of all
     groups in the pattern are also returned as part of the resulting
     list.  If maxsplit is nonzero, at most maxsplit splits occur,
     and the remainder of the string is returned as the final element
     of the list."""
+    if args:
+        if maxsplit is not _zero_sentinel:
+            raise TypeError("split() got multiple values for argument 'maxsplit'")
+        maxsplit, *args = args
+        if args:
+            if flags is not _zero_sentinel:
+                raise TypeError("split() got multiple values for argument 'flags'")
+            flags, *args = args
+            if args:
+                raise TypeError("split() takes from 2 to 4 positional arguments "
+                                "but %d were given" % (4 + len(args)))
+
+        import warnings
+        warnings.warn(
+            "'maxsplit' is passed as positional argument",
+            DeprecationWarning, stacklevel=2
+        )
+
     return _compile(pattern, flags).split(string, maxsplit)
+split.__text_signature__ = '(pattern, string, maxsplit=0, flags=0)'
 
 def findall(pattern, string, flags=0):
     """Return a list of all non-overlapping matches in the string.
@@ -254,11 +290,9 @@ def compile(pattern, flags=0):
 def purge():
     "Clear the regular expression caches"
     _cache.clear()
-    _compile_repl.cache_clear()
+    _cache2.clear()
+    _compile_template.cache_clear()
 
-def template(pattern, flags=0):
-    "Compile a template pattern, returning a Pattern object"
-    return _compile(pattern, flags|T)
 
 # SPECIAL_CHARS
 # closing ')', '}' and ']'
@@ -277,60 +311,69 @@ def escape(pattern):
         pattern = str(pattern, 'latin1')
         return pattern.translate(_special_chars_map).encode('latin1')
 
-Pattern = type(sre_compile.compile('', 0))
-Match = type(sre_compile.compile('', 0).match(''))
+Pattern = type(_compiler.compile('', 0))
+Match = type(_compiler.compile('', 0).match(''))
 
 # --------------------------------------------------------------------
 # internals
 
-_cache = {}  # ordered!
-
+# Use the fact that dict keeps the insertion order.
+# _cache2 uses the simple FIFO policy which has better latency.
+# _cache uses the LRU policy which has better hit rate.
+_cache = {}  # LRU
+_cache2 = {}  # FIFO
 _MAXCACHE = 512
+_MAXCACHE2 = 256
+assert _MAXCACHE2 < _MAXCACHE
+
 def _compile(pattern, flags):
     # internal: compile pattern
     if isinstance(flags, RegexFlag):
         flags = flags.value
     try:
-        return _cache[type(pattern), pattern, flags]
+        return _cache2[type(pattern), pattern, flags]
     except KeyError:
         pass
-    if isinstance(pattern, Pattern):
-        if flags:
-            raise ValueError(
-                "cannot process flags argument with a compiled pattern")
-        return pattern
-    if not sre_compile.isstring(pattern):
-        raise TypeError("first argument must be string or compiled pattern")
-    p = sre_compile.compile(pattern, flags)
-    if not (flags & DEBUG):
+
+    key = (type(pattern), pattern, flags)
+    # Item in _cache should be moved to the end if found.
+    p = _cache.pop(key, None)
+    if p is None:
+        if isinstance(pattern, Pattern):
+            if flags:
+                raise ValueError(
+                    "cannot process flags argument with a compiled pattern")
+            return pattern
+        if not _compiler.isstring(pattern):
+            raise TypeError("first argument must be string or compiled pattern")
+        p = _compiler.compile(pattern, flags)
+        if flags & DEBUG:
+            return p
         if len(_cache) >= _MAXCACHE:
-            # Drop the oldest item
+            # Drop the least recently used item.
+            # next(iter(_cache)) is known to have linear amortized time,
+            # but it is used here to avoid a dependency from using OrderedDict.
+            # For the small _MAXCACHE value it doesn't make much of a difference.
             try:
                 del _cache[next(iter(_cache))]
             except (StopIteration, RuntimeError, KeyError):
                 pass
-        _cache[type(pattern), pattern, flags] = p
+    # Append to the end.
+    _cache[key] = p
+
+    if len(_cache2) >= _MAXCACHE2:
+        # Drop the oldest item.
+        try:
+            del _cache2[next(iter(_cache2))]
+        except (StopIteration, RuntimeError, KeyError):
+            pass
+    _cache2[key] = p
     return p
 
 @functools.lru_cache(_MAXCACHE)
-def _compile_repl(repl, pattern):
+def _compile_template(pattern, repl):
     # internal: compile replacement pattern
-    return sre_parse.parse_template(repl, pattern)
-
-def _expand(pattern, match, template):
-    # internal: Match.expand implementation hook
-    template = sre_parse.parse_template(template, pattern)
-    return sre_parse.expand_template(template, match)
-
-def _subx(pattern, template):
-    # internal: Pattern.sub/subn implementation helper
-    template = _compile_repl(template, pattern)
-    if not template[0] and len(template[1]) == 1:
-        # literal replacement
-        return template[1][0]
-    def filter(match, template=template):
-        return sre_parse.expand_template(template, match)
-    return filter
+    return _sre.template(pattern, _parser.parse_template(repl, pattern))
 
 # register myself for pickling
 
@@ -346,22 +389,22 @@ def _pickle(p):
 
 class Scanner:
     def __init__(self, lexicon, flags=0):
-        from sre_constants import BRANCH, SUBPATTERN
+        from ._constants import BRANCH, SUBPATTERN
         if isinstance(flags, RegexFlag):
             flags = flags.value
         self.lexicon = lexicon
         # combine phrases into a compound pattern
         p = []
-        s = sre_parse.State()
+        s = _parser.State()
         s.flags = flags
         for phrase, action in lexicon:
             gid = s.opengroup()
-            p.append(sre_parse.SubPattern(s, [
-                (SUBPATTERN, (gid, 0, 0, sre_parse.parse(phrase, flags))),
+            p.append(_parser.SubPattern(s, [
+                (SUBPATTERN, (gid, 0, 0, _parser.parse(phrase, flags))),
                 ]))
             s.closegroup(gid, p[-1])
-        p = sre_parse.SubPattern(s, [(BRANCH, (None, p))])
-        self.scanner = sre_compile.compile(p)
+        p = _parser.SubPattern(s, [(BRANCH, (None, p))])
+        self.scanner = _compiler.compile(p)
     def scan(self, string):
         result = []
         append = result.append