# util.py
import inspect
import warnings
import types
import collections
import itertools
from functools import lru_cache, wraps
from typing import Callable, List, Union, Iterable, TypeVar, cast
_bslash = chr(92)
C = TypeVar("C", bound=Callable)
class __config_flags:
"""Internal class for defining compatibility and debugging flags"""
_all_names: List[str] = []
_fixed_names: List[str] = []
_type_desc = "configuration"
@classmethod
def _set(cls, dname, value):
if dname in cls._fixed_names:
warnings.warn(
f"{cls.__name__}.{dname} {cls._type_desc} is {str(getattr(cls, dname)).upper()}"
f" and cannot be overridden",
stacklevel=3,
)
return
if dname in cls._all_names:
setattr(cls, dname, value)
else:
raise ValueError(f"no such {cls._type_desc} {dname!r}")
enable = classmethod(lambda cls, name: cls._set(name, True))
disable = classmethod(lambda cls, name: cls._set(name, False))
@lru_cache(maxsize=128)
def col(loc: int, strg: str) -> int:
"""
Returns current column within a string, counting newlines as line separators.
The first column is number 1.
Note: the default parsing behavior is to expand tabs in the input string
before starting the parsing process. See
:class:`ParserElement.parse_string` for more
information on parsing strings containing ``<TAB>`` s, and suggested
methods to maintain a consistent view of the parsed string, the parse
location, and line and column positions within the parsed string.
"""
s = strg
return 1 if 0 < loc < len(s) and s[loc - 1] == "\n" else loc - s.rfind("\n", 0, loc)
@lru_cache(maxsize=128)
def lineno(loc: int, strg: str) -> int:
"""Returns current line number within a string, counting newlines as line separators.
The first line is number 1.
Note - the default parsing behavior is to expand tabs in the input string
before starting the parsing process. See :class:`ParserElement.parse_string`
for more information on parsing strings containing ``<TAB>`` s, and
suggested methods to maintain a consistent view of the parsed string, the
parse location, and line and column positions within the parsed string.
"""
return strg.count("\n", 0, loc) + 1
@lru_cache(maxsize=128)
def line(loc: int, strg: str) -> str:
"""
Returns the line of text containing loc within a string, counting newlines as line separators.
"""
last_cr = strg.rfind("\n", 0, loc)
next_cr = strg.find("\n", loc)
return strg[last_cr + 1 : next_cr] if next_cr >= 0 else strg[last_cr + 1 :]
class _UnboundedCache:
def __init__(self):
cache = {}
cache_get = cache.get
self.not_in_cache = not_in_cache = object()
def get(_, key):
return cache_get(key, not_in_cache)
def set_(_, key, value):
cache[key] = value
def clear(_):
cache.clear()
self.size = None
self.get = types.MethodType(get, self)
self.set = types.MethodType(set_, self)
self.clear = types.MethodType(clear, self)
class _FifoCache:
def __init__(self, size):
self.not_in_cache = not_in_cache = object()
cache = {}
keyring = [object()] * size
cache_get = cache.get
cache_pop = cache.pop
keyiter = itertools.cycle(range(size))
def get(_, key):
return cache_get(key, not_in_cache)
def set_(_, key, value):
cache[key] = value
i = next(keyiter)
cache_pop(keyring[i], None)
keyring[i] = key
def clear(_):
cache.clear()
keyring[:] = [object()] * size
self.size = size
self.get = types.MethodType(get, self)
self.set = types.MethodType(set_, self)
self.clear = types.MethodType(clear, self)
class LRUMemo:
"""
A memoizing mapping that retains `capacity` deleted items
The memo tracks retained items by their access order; once `capacity` items
are retained, the least recently used item is discarded.
"""
def __init__(self, capacity):
self._capacity = capacity
self._active = {}
self._memory = collections.OrderedDict()
def __getitem__(self, key):
try:
return self._active[key]
except KeyError:
self._memory.move_to_end(key)
return self._memory[key]
def __setitem__(self, key, value):
self._memory.pop(key, None)
self._active[key] = value
def __delitem__(self, key):
try:
value = self._active.pop(key)
except KeyError:
pass
else:
while len(self._memory) >= self._capacity:
self._memory.popitem(last=False)
self._memory[key] = value
def clear(self):
self._active.clear()
self._memory.clear()
class UnboundedMemo(dict):
"""
A memoizing mapping that retains all deleted items
"""
def __delitem__(self, key):
pass
def _escape_regex_range_chars(s: str) -> str:
# escape these chars: ^-[]
for c in r"\^-[]":
s = s.replace(c, _bslash + c)
s = s.replace("\n", r"\n")
s = s.replace("\t", r"\t")
return str(s)
def _collapse_string_to_ranges(
s: Union[str, Iterable[str]], re_escape: bool = True
) -> str:
def is_consecutive(c):
c_int = ord(c)
is_consecutive.prev, prev = c_int, is_consecutive.prev
if c_int - prev > 1:
is_consecutive.value = next(is_consecutive.counter)
return is_consecutive.value
is_consecutive.prev = 0 # type: ignore [attr-defined]
is_consecutive.counter = itertools.count() # type: ignore [attr-defined]
is_consecutive.value = -1 # type: ignore [attr-defined]
def escape_re_range_char(c):
return "\\" + c if c in r"\^-][" else c
def no_escape_re_range_char(c):
return c
if not re_escape:
escape_re_range_char = no_escape_re_range_char
ret = []
s = "".join(sorted(set(s)))
if len(s) > 3:
for _, chars in itertools.groupby(s, key=is_consecutive):
first = last = next(chars)
last = collections.deque(
itertools.chain(iter([last]), chars), maxlen=1
).pop()
if first == last:
ret.append(escape_re_range_char(first))
else:
sep = "" if ord(last) == ord(first) + 1 else "-"
ret.append(
f"{escape_re_range_char(first)}{sep}{escape_re_range_char(last)}"
)
else:
ret = [escape_re_range_char(c) for c in s]
return "".join(ret)
def _flatten(ll: list) -> list:
ret = []
for i in ll:
if isinstance(i, list):
ret.extend(_flatten(i))
else:
ret.append(i)
return ret
def _make_synonym_function(compat_name: str, fn: C) -> C:
# In a future version, uncomment the code in the internal _inner() functions
# to begin emitting DeprecationWarnings.
# Unwrap staticmethod/classmethod
fn = getattr(fn, "__func__", fn)
# (Presence of 'self' arg in signature is used by explain_exception() methods, so we take
# some extra steps to add it if present in decorated function.)
if "self" == list(inspect.signature(fn).parameters)[0]:
@wraps(fn)
def _inner(self, *args, **kwargs):
# warnings.warn(
# f"Deprecated - use {fn.__name__}", DeprecationWarning, stacklevel=3
# )
return fn(self, *args, **kwargs)
else:
@wraps(fn)
def _inner(*args, **kwargs):
# warnings.warn(
# f"Deprecated - use {fn.__name__}", DeprecationWarning, stacklevel=3
# )
return fn(*args, **kwargs)
_inner.__doc__ = f"""Deprecated - use :class:`{fn.__name__}`"""
_inner.__name__ = compat_name
_inner.__annotations__ = fn.__annotations__
if isinstance(fn, types.FunctionType):
_inner.__kwdefaults__ = fn.__kwdefaults__
elif isinstance(fn, type) and hasattr(fn, "__init__"):
_inner.__kwdefaults__ = fn.__init__.__kwdefaults__
else:
_inner.__kwdefaults__ = None
_inner.__qualname__ = fn.__qualname__
return cast(C, _inner)
def replaced_by_pep8(fn: C) -> Callable[[Callable], C]:
"""
Decorator for pre-PEP8 compatibility synonyms, to link them to the new function.
"""
return lambda other: _make_synonym_function(other.__name__, fn)