X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/62402a32618bc62ae90cfcdc3d47c7ad20e60e10..1d2ed2bb421df94a8d86728a187663f1c3898322:/src/black/trans.py diff --git a/src/black/trans.py b/src/black/trans.py index 023dcd3..cb41c1b 100644 --- a/src/black/trans.py +++ b/src/black/trans.py @@ -4,10 +4,11 @@ String transformers that can split and merge strings. from abc import ABC, abstractmethod from collections import defaultdict from dataclasses import dataclass -import regex as re +import re from typing import ( Any, Callable, + ClassVar, Collection, Dict, Iterable, @@ -20,6 +21,14 @@ from typing import ( TypeVar, Union, ) +import sys + +if sys.version_info < (3, 8): + from typing_extensions import Final +else: + from typing import Final + +from mypy_extensions import trait from black.rusty import Result, Ok, Err @@ -62,7 +71,6 @@ def TErr(err_msg: str) -> Err[CannotTransform]: return Err(cant_transform) -@dataclass # type: ignore class StringTransformer(ABC): """ An implementation of the Transformer protocol that relies on its @@ -90,9 +98,13 @@ class StringTransformer(ABC): as much as possible. """ - line_length: int - normalize_strings: bool - __name__ = "StringTransformer" + __name__: Final = "StringTransformer" + + # Ideally this would be a dataclass, but unfortunately mypyc breaks when used with + # `abc.ABC`. + def __init__(self, line_length: int, normalize_strings: bool) -> None: + self.line_length = line_length + self.normalize_strings = normalize_strings @abstractmethod def do_match(self, line: Line) -> TMatchResult: @@ -184,6 +196,7 @@ class CustomSplit: break_idx: int +@trait class CustomSplitMapMixin: """ This mixin class is used to map merged strings to a sequence of @@ -191,8 +204,10 @@ class CustomSplitMapMixin: the resultant substrings go over the configured max line length. """ - _Key = Tuple[StringID, str] - _CUSTOM_SPLIT_MAP: Dict[_Key, Tuple[CustomSplit, ...]] = defaultdict(tuple) + _Key: ClassVar = Tuple[StringID, str] + _CUSTOM_SPLIT_MAP: ClassVar[Dict[_Key, Tuple[CustomSplit, ...]]] = defaultdict( + tuple + ) @staticmethod def _get_key(string: str) -> "CustomSplitMapMixin._Key": @@ -243,7 +258,7 @@ class CustomSplitMapMixin: return key in self._CUSTOM_SPLIT_MAP -class StringMerger(CustomSplitMapMixin, StringTransformer): +class StringMerger(StringTransformer, CustomSplitMapMixin): """StringTransformer that merges strings together. Requirements: @@ -438,7 +453,7 @@ class StringMerger(CustomSplitMapMixin, StringTransformer): # with 'f'... if "f" in prefix and "f" not in next_prefix: # Then we must escape any braces contained in this substring. - SS = re.subf(r"(\{|\})", "{1}{1}", SS) + SS = re.sub(r"(\{|\})", r"\1\1", SS) NSS = make_naked(SS, next_prefix) @@ -739,7 +754,7 @@ class BaseStringSplitter(StringTransformer): * The target string is not a multiline (i.e. triple-quote) string. """ - STRING_OPERATORS = [ + STRING_OPERATORS: Final = [ token.EQEQUAL, token.GREATER, token.GREATEREQUAL, @@ -927,7 +942,58 @@ class BaseStringSplitter(StringTransformer): return max_string_length -class StringSplitter(CustomSplitMapMixin, BaseStringSplitter): +def iter_fexpr_spans(s: str) -> Iterator[Tuple[int, int]]: + """ + Yields spans corresponding to expressions in a given f-string. + Spans are half-open ranges (left inclusive, right exclusive). + Assumes the input string is a valid f-string, but will not crash if the input + string is invalid. + """ + stack: List[int] = [] # our curly paren stack + i = 0 + while i < len(s): + if s[i] == "{": + # if we're in a string part of the f-string, ignore escaped curly braces + if not stack and i + 1 < len(s) and s[i + 1] == "{": + i += 2 + continue + stack.append(i) + i += 1 + continue + + if s[i] == "}": + if not stack: + i += 1 + continue + j = stack.pop() + # we've made it back out of the expression! yield the span + if not stack: + yield (j, i + 1) + i += 1 + continue + + # if we're in an expression part of the f-string, fast forward through strings + # note that backslashes are not legal in the expression portion of f-strings + if stack: + delim = None + if s[i : i + 3] in ("'''", '"""'): + delim = s[i : i + 3] + elif s[i] in ("'", '"'): + delim = s[i] + if delim: + i += len(delim) + while i < len(s) and s[i : i + len(delim)] != delim: + i += 1 + i += len(delim) + continue + i += 1 + + +def fstring_contains_expr(s: str) -> bool: + return any(iter_fexpr_spans(s)) + + +class StringSplitter(BaseStringSplitter, CustomSplitMapMixin): """ StringTransformer that splits "atom" strings (i.e. strings which exist on lines by themselves). @@ -965,18 +1031,7 @@ class StringSplitter(CustomSplitMapMixin, BaseStringSplitter): CustomSplit objects and add them to the custom split map. """ - MIN_SUBSTR_SIZE = 6 - # Matches an "f-expression" (e.g. {var}) that might be found in an f-string. - RE_FEXPR = r""" - (? TMatchResult: LL = line.leaves @@ -1043,8 +1098,8 @@ class StringSplitter(CustomSplitMapMixin, BaseStringSplitter): # contain any f-expressions, but ONLY if the original f-string # contains at least one f-expression. Otherwise, we will alter the AST # of the program. - drop_pointless_f_prefix = ("f" in prefix) and re.search( - self.RE_FEXPR, LL[string_idx].value, re.VERBOSE + drop_pointless_f_prefix = ("f" in prefix) and fstring_contains_expr( + LL[string_idx].value ) first_string_line = True @@ -1284,9 +1339,7 @@ class StringSplitter(CustomSplitMapMixin, BaseStringSplitter): """ if "f" not in get_string_prefix(string).lower(): return - - for match in re.finditer(self.RE_FEXPR, string, re.VERBOSE): - yield match.span() + yield from iter_fexpr_spans(string) def _get_illegal_split_indices(self, string: str) -> Set[Index]: illegal_indices: Set[Index] = set() @@ -1402,7 +1455,7 @@ class StringSplitter(CustomSplitMapMixin, BaseStringSplitter): """ assert_is_leaf_string(string) - if "f" in prefix and not re.search(self.RE_FEXPR, string, re.VERBOSE): + if "f" in prefix and not fstring_contains_expr(string): new_prefix = prefix.replace("f", "") temp = string[len(prefix) :] @@ -1426,7 +1479,7 @@ class StringSplitter(CustomSplitMapMixin, BaseStringSplitter): return string_op_leaves -class StringParenWrapper(CustomSplitMapMixin, BaseStringSplitter): +class StringParenWrapper(BaseStringSplitter, CustomSplitMapMixin): """ StringTransformer that splits non-"atom" strings (i.e. strings that do not exist on lines by themselves). @@ -1811,20 +1864,20 @@ class StringParser: ``` """ - DEFAULT_TOKEN = -1 + DEFAULT_TOKEN: Final = 20210605 # String Parser States - START = 1 - DOT = 2 - NAME = 3 - PERCENT = 4 - SINGLE_FMT_ARG = 5 - LPAR = 6 - RPAR = 7 - DONE = 8 + START: Final = 1 + DOT: Final = 2 + NAME: Final = 3 + PERCENT: Final = 4 + SINGLE_FMT_ARG: Final = 5 + LPAR: Final = 6 + RPAR: Final = 7 + DONE: Final = 8 # Lookup Table for Next State - _goto: Dict[Tuple[ParserState, NodeType], ParserState] = { + _goto: Final[Dict[Tuple[ParserState, NodeType], ParserState]] = { # A string trailer may start with '.' OR '%'. (START, token.DOT): DOT, (START, token.PERCENT): PERCENT,