X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/a4e35b314977baae2e930abd24fa1013c7235e39..e401b6bb1e1c0ed534bba59d9dc908caf7ba898c:/src/black/trans.py diff --git a/src/black/trans.py b/src/black/trans.py index bc6e93b..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, @@ -15,10 +16,19 @@ from typing import ( List, Optional, Sequence, + Set, Tuple, 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 @@ -61,7 +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 @@ -89,9 +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: @@ -183,6 +196,7 @@ class CustomSplit: break_idx: int +@trait class CustomSplitMapMixin: """ This mixin class is used to map merged strings to a sequence of @@ -190,8 +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": @@ -242,7 +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: @@ -411,7 +427,7 @@ class StringMerger(CustomSplitMapMixin, StringTransformer): and is_valid_index(next_str_idx) and LL[next_str_idx].type == token.STRING ): - prefix = get_string_prefix(LL[next_str_idx].value) + prefix = get_string_prefix(LL[next_str_idx].value).lower() next_str_idx += 1 # The next loop merges the string group. The final string will be @@ -431,13 +447,13 @@ class StringMerger(CustomSplitMapMixin, StringTransformer): num_of_strings += 1 SS = LL[next_str_idx].value - next_prefix = get_string_prefix(SS) + next_prefix = get_string_prefix(SS).lower() # If this is an f-string group but this substring is not prefixed # 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) @@ -541,7 +557,7 @@ class StringMerger(CustomSplitMapMixin, StringTransformer): return TErr("StringMerger does NOT merge multiline strings.") num_of_strings += 1 - prefix = get_string_prefix(leaf.value) + prefix = get_string_prefix(leaf.value).lower() if "r" in prefix: return TErr("StringMerger does NOT merge raw strings.") @@ -738,7 +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, @@ -867,7 +883,7 @@ class BaseStringSplitter(StringTransformer): # WMA4 a space, a comma, and a closing bracket [e.g. `), STRING`]. offset += 3 - if P.type in [token.COLON, token.EQUAL, token.NAME]: + if P.type in [token.COLON, token.EQUAL, token.PLUSEQUAL, token.NAME]: # This conditional branch is meant to handle dictionary keys, # variable assignments, 'return STRING' statement lines, and # 'else STRING' ternary expression lines. @@ -926,7 +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). @@ -964,18 +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 @@ -1036,14 +1092,14 @@ class StringSplitter(CustomSplitMapMixin, BaseStringSplitter): is_valid_index = is_valid_index_factory(LL) insert_str_child = insert_str_child_factory(LL[string_idx]) - prefix = get_string_prefix(LL[string_idx].value) + prefix = get_string_prefix(LL[string_idx].value).lower() # We MAY choose to drop the 'f' prefix from substrings that don't # 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 @@ -1151,21 +1207,32 @@ class StringSplitter(CustomSplitMapMixin, BaseStringSplitter): # --- Construct `next_value` next_value = rest_value[:break_idx] + QUOTE + + # HACK: The following 'if' statement is a hack to fix the custom + # breakpoint index in the case of either: (a) substrings that were + # f-strings but will have the 'f' prefix removed OR (b) substrings + # that were not f-strings but will now become f-strings because of + # redundant use of the 'f' prefix (i.e. none of the substrings + # contain f-expressions but one or more of them had the 'f' prefix + # anyway; in which case, we will prepend 'f' to _all_ substrings). + # + # There is probably a better way to accomplish what is being done + # here... + # + # If this substring is an f-string, we _could_ remove the 'f' + # prefix, and the current custom split did NOT originally use a + # prefix... if ( - # Are we allowed to try to drop a pointless 'f' prefix? - drop_pointless_f_prefix - # If we are, will we be successful? - and next_value != self._normalize_f_string(next_value, prefix) + next_value != self._normalize_f_string(next_value, prefix) + and use_custom_breakpoints + and not csplit.has_prefix ): - # If the current custom split did NOT originally use a prefix, - # then `csplit.break_idx` will be off by one after removing + # Then `csplit.break_idx` will be off by one after removing # the 'f' prefix. - break_idx = ( - break_idx + 1 - if use_custom_breakpoints and not csplit.has_prefix - else break_idx - ) + break_idx += 1 next_value = rest_value[:break_idx] + QUOTE + + if drop_pointless_f_prefix: next_value = self._normalize_f_string(next_value, prefix) # --- Construct `next_leaf` @@ -1232,6 +1299,59 @@ class StringSplitter(CustomSplitMapMixin, BaseStringSplitter): last_line.comments = line.comments.copy() yield Ok(last_line) + def _iter_nameescape_slices(self, string: str) -> Iterator[Tuple[Index, Index]]: + """ + Yields: + All ranges of @string which, if @string were to be split there, + would result in the splitting of an \\N{...} expression (which is NOT + allowed). + """ + # True - the previous backslash was unescaped + # False - the previous backslash was escaped *or* there was no backslash + previous_was_unescaped_backslash = False + it = iter(enumerate(string)) + for idx, c in it: + if c == "\\": + previous_was_unescaped_backslash = not previous_was_unescaped_backslash + continue + if not previous_was_unescaped_backslash or c != "N": + previous_was_unescaped_backslash = False + continue + previous_was_unescaped_backslash = False + + begin = idx - 1 # the position of backslash before \N{...} + for idx, c in it: + if c == "}": + end = idx + break + else: + # malformed nameescape expression? + # should have been detected by AST parsing earlier... + raise RuntimeError(f"{self.__class__.__name__} LOGIC ERROR!") + yield begin, end + + def _iter_fexpr_slices(self, string: str) -> Iterator[Tuple[Index, Index]]: + """ + Yields: + All ranges of @string which, if @string were to be split there, + would result in the splitting of an f-expression (which is NOT + allowed). + """ + if "f" not in get_string_prefix(string).lower(): + return + yield from iter_fexpr_spans(string) + + def _get_illegal_split_indices(self, string: str) -> Set[Index]: + illegal_indices: Set[Index] = set() + iterators = [ + self._iter_fexpr_slices(string), + self._iter_nameescape_slices(string), + ] + for it in iterators: + for begin, end in it: + illegal_indices.update(range(begin, end + 1)) + return illegal_indices + def _get_break_idx(self, string: str, max_break_idx: int) -> Optional[int]: """ This method contains the algorithm that StringSplitter uses to @@ -1261,40 +1381,15 @@ class StringSplitter(CustomSplitMapMixin, BaseStringSplitter): assert is_valid_index(max_break_idx) assert_is_leaf_string(string) - _fexpr_slices: Optional[List[Tuple[Index, Index]]] = None + _illegal_split_indices = self._get_illegal_split_indices(string) - def fexpr_slices() -> Iterator[Tuple[Index, Index]]: - """ - Yields: - All ranges of @string which, if @string were to be split there, - would result in the splitting of an f-expression (which is NOT - allowed). - """ - nonlocal _fexpr_slices - - if _fexpr_slices is None: - _fexpr_slices = [] - for match in re.finditer(self.RE_FEXPR, string, re.VERBOSE): - _fexpr_slices.append(match.span()) - - yield from _fexpr_slices - - is_fstring = "f" in get_string_prefix(string) - - def breaks_fstring_expression(i: Index) -> bool: + def breaks_unsplittable_expression(i: Index) -> bool: """ Returns: True iff returning @i would result in the splitting of an - f-expression (which is NOT allowed). + unsplittable expression (which is NOT allowed). """ - if not is_fstring: - return False - - for (start, end) in fexpr_slices(): - if start <= i < end: - return True - - return False + return i in _illegal_split_indices def passes_all_checks(i: Index) -> bool: """ @@ -1318,7 +1413,7 @@ class StringSplitter(CustomSplitMapMixin, BaseStringSplitter): is_space and is_not_escaped and is_big_enough - and not breaks_fstring_expression(i) + and not breaks_unsplittable_expression(i) ) # First, we check all indices BELOW @max_break_idx. @@ -1360,7 +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) :] @@ -1384,7 +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). @@ -1769,20 +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,