"""
String transformers that can split and merge strings.
"""
+import re
+import sys
from abc import ABC, abstractmethod
from collections import defaultdict
from dataclasses import dataclass
-import regex as re
from typing import (
Any,
Callable,
+ ClassVar,
Collection,
Dict,
Iterable,
List,
Optional,
Sequence,
+ Set,
Tuple,
TypeVar,
Union,
)
-from black.rusty import Result, Ok, Err
+if sys.version_info < (3, 8):
+ from typing_extensions import Final, Literal
+else:
+ from typing import Literal, Final
-from black.mode import Feature
-from black.nodes import syms, replace_child, parent_type
-from black.nodes import is_empty_par, is_empty_lpar, is_empty_rpar
-from black.nodes import OPENING_BRACKETS, CLOSING_BRACKETS, STANDALONE_COMMENT
-from black.lines import Line, append_leaves
-from black.brackets import BracketMatchError
-from black.comments import contains_pragma_comment
-from black.strings import has_triple_quotes, get_string_prefix, assert_is_leaf_string
-from black.strings import normalize_string_quotes
+from mypy_extensions import trait
-from blib2to3.pytree import Leaf, Node
+from black.comments import contains_pragma_comment
+from black.lines import Line, append_leaves
+from black.mode import Feature, Mode
+from black.nodes import (
+ CLOSING_BRACKETS,
+ OPENING_BRACKETS,
+ STANDALONE_COMMENT,
+ is_empty_lpar,
+ is_empty_par,
+ is_empty_rpar,
+ is_part_of_annotation,
+ parent_type,
+ replace_child,
+ syms,
+)
+from black.rusty import Err, Ok, Result
+from black.strings import (
+ assert_is_leaf_string,
+ get_string_prefix,
+ has_triple_quotes,
+ normalize_string_quotes,
+)
from blib2to3.pgen2 import token
+from blib2to3.pytree import Leaf, Node
class CannotTransform(Exception):
# types
T = TypeVar("T")
LN = Union[Leaf, Node]
-Transformer = Callable[[Line, Collection[Feature]], Iterator[Line]]
+Transformer = Callable[[Line, Collection[Feature], Mode], Iterator[Line]]
Index = int
NodeType = int
ParserState = int
StringID = int
TResult = Result[T, CannotTransform] # (T)ransform Result
-TMatchResult = TResult[Index]
+TMatchResult = TResult[List[Index]]
def TErr(err_msg: str) -> Err[CannotTransform]:
return Err(cant_transform)
-@dataclass # type: ignore
+def hug_power_op(
+ line: Line, features: Collection[Feature], mode: Mode
+) -> Iterator[Line]:
+ """A transformer which normalizes spacing around power operators."""
+
+ # Performance optimization to avoid unnecessary Leaf clones and other ops.
+ for leaf in line.leaves:
+ if leaf.type == token.DOUBLESTAR:
+ break
+ else:
+ raise CannotTransform("No doublestar token was found in the line.")
+
+ def is_simple_lookup(index: int, step: Literal[1, -1]) -> bool:
+ # Brackets and parentheses indicate calls, subscripts, etc. ...
+ # basically stuff that doesn't count as "simple". Only a NAME lookup
+ # or dotted lookup (eg. NAME.NAME) is OK.
+ if step == -1:
+ disallowed = {token.RPAR, token.RSQB}
+ else:
+ disallowed = {token.LPAR, token.LSQB}
+
+ while 0 <= index < len(line.leaves):
+ current = line.leaves[index]
+ if current.type in disallowed:
+ return False
+ if current.type not in {token.NAME, token.DOT} or current.value == "for":
+ # If the current token isn't disallowed, we'll assume this is simple as
+ # only the disallowed tokens are semantically attached to this lookup
+ # expression we're checking. Also, stop early if we hit the 'for' bit
+ # of a comprehension.
+ return True
+
+ index += step
+
+ return True
+
+ def is_simple_operand(index: int, kind: Literal["base", "exponent"]) -> bool:
+ # An operand is considered "simple" if's a NAME, a numeric CONSTANT, a simple
+ # lookup (see above), with or without a preceding unary operator.
+ start = line.leaves[index]
+ if start.type in {token.NAME, token.NUMBER}:
+ return is_simple_lookup(index, step=(1 if kind == "exponent" else -1))
+
+ if start.type in {token.PLUS, token.MINUS, token.TILDE}:
+ if line.leaves[index + 1].type in {token.NAME, token.NUMBER}:
+ # step is always one as bases with a preceding unary op will be checked
+ # for simplicity starting from the next token (so it'll hit the check
+ # above).
+ return is_simple_lookup(index + 1, step=1)
+
+ return False
+
+ new_line = line.clone()
+ should_hug = False
+ for idx, leaf in enumerate(line.leaves):
+ new_leaf = leaf.clone()
+ if should_hug:
+ new_leaf.prefix = ""
+ should_hug = False
+
+ should_hug = (
+ (0 < idx < len(line.leaves) - 1)
+ and leaf.type == token.DOUBLESTAR
+ and is_simple_operand(idx - 1, kind="base")
+ and line.leaves[idx - 1].value != "lambda"
+ and is_simple_operand(idx + 1, kind="exponent")
+ )
+ if should_hug:
+ new_leaf.prefix = ""
+
+ # We have to be careful to make a new line properly:
+ # - bracket related metadata must be maintained (handled by Line.append)
+ # - comments need to copied over, updating the leaf IDs they're attached to
+ new_line.append(new_leaf, preformatted=True)
+ for comment_leaf in line.comments_after(leaf):
+ new_line.append(comment_leaf, preformatted=True)
+
+ yield new_line
+
+
class StringTransformer(ABC):
"""
An implementation of the Transformer protocol that relies on its
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:
"""
Returns:
- * Ok(string_idx) such that `line.leaves[string_idx]` is our target
- string, if a match was able to be made.
+ * Ok(string_indices) such that for each index, `line.leaves[index]`
+ is our target string if a match was able to be made. For
+ transformers that don't result in more lines (e.g. StringMerger,
+ StringParenStripper), multiple matches and transforms are done at
+ once to reduce the complexity.
OR
- * Err(CannotTransform), if a match was not able to be made.
+ * Err(CannotTransform), if no match could be made.
"""
@abstractmethod
- def do_transform(self, line: Line, string_idx: int) -> Iterator[TResult[Line]]:
+ def do_transform(
+ self, line: Line, string_indices: List[int]
+ ) -> Iterator[TResult[Line]]:
"""
Yields:
* Ok(new_line) where new_line is the new transformed line.
yield an CannotTransform after that point.)
"""
- def __call__(self, line: Line, _features: Collection[Feature]) -> Iterator[Line]:
+ def __call__(
+ self, line: Line, _features: Collection[Feature], _mode: Mode
+ ) -> Iterator[Line]:
"""
StringTransformer instances have a call signature that mirrors that of
the Transformer type.
" this line as one that it can transform."
) from cant_transform
- string_idx = match_result.ok()
+ string_indices = match_result.ok()
- for line_result in self.do_transform(line, string_idx):
+ for line_result in self.do_transform(line, string_indices):
if isinstance(line_result, Err):
cant_transform = line_result.err()
raise CannotTransform(
break_idx: int
+@trait
class CustomSplitMapMixin:
"""
This mixin class is used to map merged strings to a sequence of
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":
return key in self._CUSTOM_SPLIT_MAP
-class StringMerger(CustomSplitMapMixin, StringTransformer):
+class StringMerger(StringTransformer, CustomSplitMapMixin):
"""StringTransformer that merges strings together.
Requirements:
(A) The line contains adjacent strings such that ALL of the validation checks
- listed in StringMerger.__validate_msg(...)'s docstring pass.
+ listed in StringMerger._validate_msg(...)'s docstring pass.
OR
(B) The line contains a string which uses line continuation backslashes.
is_valid_index = is_valid_index_factory(LL)
- for (i, leaf) in enumerate(LL):
+ string_indices = []
+ idx = 0
+ while is_valid_index(idx):
+ leaf = LL[idx]
if (
leaf.type == token.STRING
- and is_valid_index(i + 1)
- and LL[i + 1].type == token.STRING
+ and is_valid_index(idx + 1)
+ and LL[idx + 1].type == token.STRING
):
- return Ok(i)
+ if not is_part_of_annotation(leaf):
+ string_indices.append(idx)
+
+ # Advance to the next non-STRING leaf.
+ idx += 2
+ while is_valid_index(idx) and LL[idx].type == token.STRING:
+ idx += 1
- if leaf.type == token.STRING and "\\\n" in leaf.value:
- return Ok(i)
+ elif leaf.type == token.STRING and "\\\n" in leaf.value:
+ string_indices.append(idx)
+ # Advance to the next non-STRING leaf.
+ idx += 1
+ while is_valid_index(idx) and LL[idx].type == token.STRING:
+ idx += 1
+
+ else:
+ idx += 1
- return TErr("This line has no strings that need merging.")
+ if string_indices:
+ return Ok(string_indices)
+ else:
+ return TErr("This line has no strings that need merging.")
- def do_transform(self, line: Line, string_idx: int) -> Iterator[TResult[Line]]:
+ def do_transform(
+ self, line: Line, string_indices: List[int]
+ ) -> Iterator[TResult[Line]]:
new_line = line
+
rblc_result = self._remove_backslash_line_continuation_chars(
- new_line, string_idx
+ new_line, string_indices
)
if isinstance(rblc_result, Ok):
new_line = rblc_result.ok()
- msg_result = self._merge_string_group(new_line, string_idx)
+ msg_result = self._merge_string_group(new_line, string_indices)
if isinstance(msg_result, Ok):
new_line = msg_result.ok()
@staticmethod
def _remove_backslash_line_continuation_chars(
- line: Line, string_idx: int
+ line: Line, string_indices: List[int]
) -> TResult[Line]:
"""
Merge strings that were split across multiple lines using
"""
LL = line.leaves
- string_leaf = LL[string_idx]
- if not (
- string_leaf.type == token.STRING
- and "\\\n" in string_leaf.value
- and not has_triple_quotes(string_leaf.value)
- ):
+ indices_to_transform = []
+ for string_idx in string_indices:
+ string_leaf = LL[string_idx]
+ if (
+ string_leaf.type == token.STRING
+ and "\\\n" in string_leaf.value
+ and not has_triple_quotes(string_leaf.value)
+ ):
+ indices_to_transform.append(string_idx)
+
+ if not indices_to_transform:
return TErr(
- f"String leaf {string_leaf} does not contain any backslash line"
- " continuation characters."
+ "Found no string leaves that contain backslash line continuation"
+ " characters."
)
new_line = line.clone()
new_line.comments = line.comments.copy()
append_leaves(new_line, line, LL)
- new_string_leaf = new_line.leaves[string_idx]
- new_string_leaf.value = new_string_leaf.value.replace("\\\n", "")
+ for string_idx in indices_to_transform:
+ new_string_leaf = new_line.leaves[string_idx]
+ new_string_leaf.value = new_string_leaf.value.replace("\\\n", "")
return Ok(new_line)
- def _merge_string_group(self, line: Line, string_idx: int) -> TResult[Line]:
+ def _merge_string_group(
+ self, line: Line, string_indices: List[int]
+ ) -> TResult[Line]:
"""
- Merges string group (i.e. set of adjacent strings) where the first
- string in the group is `line.leaves[string_idx]`.
+ Merges string groups (i.e. set of adjacent strings).
+
+ Each index from `string_indices` designates one string group's first
+ leaf in `line.leaves`.
Returns:
Ok(new_line), if ALL of the validation checks found in
- __validate_msg(...) pass.
+ _validate_msg(...) pass.
OR
Err(CannotTransform), otherwise.
"""
is_valid_index = is_valid_index_factory(LL)
- vresult = self._validate_msg(line, string_idx)
- if isinstance(vresult, Err):
- return vresult
+ # A dict of {string_idx: tuple[num_of_strings, string_leaf]}.
+ merged_string_idx_dict: Dict[int, Tuple[int, Leaf]] = {}
+ for string_idx in string_indices:
+ vresult = self._validate_msg(line, string_idx)
+ if isinstance(vresult, Err):
+ continue
+ merged_string_idx_dict[string_idx] = self._merge_one_string_group(
+ LL, string_idx, is_valid_index
+ )
+
+ if not merged_string_idx_dict:
+ return TErr("No string group is merged")
+ # Build the final line ('new_line') that this method will later return.
+ new_line = line.clone()
+ previous_merged_string_idx = -1
+ previous_merged_num_of_strings = -1
+ for i, leaf in enumerate(LL):
+ if i in merged_string_idx_dict:
+ previous_merged_string_idx = i
+ previous_merged_num_of_strings, string_leaf = merged_string_idx_dict[i]
+ new_line.append(string_leaf)
+
+ if (
+ previous_merged_string_idx
+ <= i
+ < previous_merged_string_idx + previous_merged_num_of_strings
+ ):
+ for comment_leaf in line.comments_after(LL[i]):
+ new_line.append(comment_leaf, preformatted=True)
+ continue
+
+ append_leaves(new_line, line, [leaf])
+
+ return Ok(new_line)
+
+ def _merge_one_string_group(
+ self, LL: List[Leaf], string_idx: int, is_valid_index: Callable[[int], bool]
+ ) -> Tuple[int, Leaf]:
+ """
+ Merges one string group where the first string in the group is
+ `LL[string_idx]`.
+
+ Returns:
+ A tuple of `(num_of_strings, leaf)` where `num_of_strings` is the
+ number of strings merged and `leaf` is the newly merged string
+ to be replaced in the new line.
+ """
# If the string group is wrapped inside an Atom node, we must make sure
# to later replace that Atom with our new (merged) string leaf.
atom_node = LL[string_idx].parent
characters have been escaped.
"""
assert_is_leaf_string(string)
+ if "f" in string_prefix:
+ string = _toggle_fexpr_quotes(string, QUOTE)
+ # After quotes toggling, quotes in expressions won't be escaped
+ # because quotes can't be reused in f-strings. So we can simply
+ # let the escaping logic below run without knowing f-string
+ # expressions.
RE_EVEN_BACKSLASHES = r"(?:(?<!\\)(?:\\\\)*)"
naked_string = string[len(string_prefix) + 1 : -1]
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
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)
next_str_idx += 1
+ # Take a note on the index of the non-STRING leaf.
+ non_string_idx = next_str_idx
+
S_leaf = Leaf(token.STRING, S)
if self.normalize_strings:
S_leaf.value = normalize_string_quotes(S_leaf.value)
string_leaf = Leaf(token.STRING, S_leaf.value.replace(BREAK_MARK, ""))
if atom_node is not None:
- replace_child(atom_node, string_leaf)
-
- # Build the final line ('new_line') that this method will later return.
- new_line = line.clone()
- for (i, leaf) in enumerate(LL):
- if i == string_idx:
- new_line.append(string_leaf)
-
- if string_idx <= i < string_idx + num_of_strings:
- for comment_leaf in line.comments_after(LL[i]):
- new_line.append(comment_leaf, preformatted=True)
- continue
-
- append_leaves(new_line, line, [leaf])
+ # If not all children of the atom node are merged (this can happen
+ # when there is a standalone comment in the middle) ...
+ if non_string_idx - string_idx < len(atom_node.children):
+ # We need to replace the old STRING leaves with the new string leaf.
+ first_child_idx = LL[string_idx].remove()
+ for idx in range(string_idx + 1, non_string_idx):
+ LL[idx].remove()
+ if first_child_idx is not None:
+ atom_node.insert_child(first_child_idx, string_leaf)
+ else:
+ # Else replace the atom node with the new string leaf.
+ replace_child(atom_node, string_leaf)
self.add_custom_splits(string_leaf.value, custom_splits)
- return Ok(new_line)
+ return num_of_strings, string_leaf
@staticmethod
def _validate_msg(line: Line, string_idx: int) -> TResult[None]:
"""Validate (M)erge (S)tring (G)roup
- Transform-time string validation logic for __merge_string_group(...).
+ Transform-time string validation logic for _merge_string_group(...).
Returns:
* Ok(None), if ALL validation checks (listed below) pass.
- The set of all string prefixes in the string group is of
length greater than one and is not equal to {"", "f"}.
- The string group consists of raw strings.
+ - The string group is stringified type annotations. We don't want to
+ process stringified type annotations since pyright doesn't support
+ them spanning multiple string values. (NOTE: mypy, pytype, pyre do
+ support them, so we can change if pyright also gains support in the
+ future. See https://github.com/microsoft/pyright/issues/4359.)
"""
# We first check for "inner" stand-alone comments (i.e. stand-alone
# comments that have a string leaf before them AND after them).
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.")
is_valid_index = is_valid_index_factory(LL)
- for (idx, leaf) in enumerate(LL):
+ string_indices = []
+
+ idx = -1
+ while True:
+ idx += 1
+ if idx >= len(LL):
+ break
+ leaf = LL[idx]
+
# Should be a string...
if leaf.type != token.STRING:
continue
}:
continue
- return Ok(string_idx)
+ string_indices.append(string_idx)
+ idx = string_idx
+ while idx < len(LL) - 1 and LL[idx + 1].type == token.STRING:
+ idx += 1
+ if string_indices:
+ return Ok(string_indices)
return TErr("This line has no strings wrapped in parens.")
- def do_transform(self, line: Line, string_idx: int) -> Iterator[TResult[Line]]:
+ def do_transform(
+ self, line: Line, string_indices: List[int]
+ ) -> Iterator[TResult[Line]]:
LL = line.leaves
- string_parser = StringParser()
- rpar_idx = string_parser.parse(LL, string_idx)
+ string_and_rpar_indices: List[int] = []
+ for string_idx in string_indices:
+ string_parser = StringParser()
+ rpar_idx = string_parser.parse(LL, string_idx)
+
+ should_transform = True
+ for leaf in (LL[string_idx - 1], LL[rpar_idx]):
+ if line.comments_after(leaf):
+ # Should not strip parentheses which have comments attached
+ # to them.
+ should_transform = False
+ break
+ if should_transform:
+ string_and_rpar_indices.extend((string_idx, rpar_idx))
- for leaf in (LL[string_idx - 1], LL[rpar_idx]):
- if line.comments_after(leaf):
- yield TErr(
- "Will not strip parentheses which have comments attached to them."
- )
- return
+ if string_and_rpar_indices:
+ yield Ok(self._transform_to_new_line(line, string_and_rpar_indices))
+ else:
+ yield Err(
+ CannotTransform("All string groups have comments attached to them.")
+ )
+
+ def _transform_to_new_line(
+ self, line: Line, string_and_rpar_indices: List[int]
+ ) -> Line:
+ LL = line.leaves
new_line = line.clone()
new_line.comments = line.comments.copy()
- try:
- append_leaves(new_line, line, LL[: string_idx - 1])
- except BracketMatchError:
- # HACK: I believe there is currently a bug somewhere in
- # right_hand_split() that is causing brackets to not be tracked
- # properly by a shared BracketTracker.
- append_leaves(new_line, line, LL[: string_idx - 1], preformatted=True)
-
- string_leaf = Leaf(token.STRING, LL[string_idx].value)
- LL[string_idx - 1].remove()
- replace_child(LL[string_idx], string_leaf)
- new_line.append(string_leaf)
-
- append_leaves(
- new_line, line, LL[string_idx + 1 : rpar_idx] + LL[rpar_idx + 1 :]
- )
- LL[rpar_idx].remove()
+ previous_idx = -1
+ # We need to sort the indices, since string_idx and its matching
+ # rpar_idx may not come in order, e.g. in
+ # `("outer" % ("inner".join(items)))`, the "inner" string's
+ # string_idx is smaller than "outer" string's rpar_idx.
+ for idx in sorted(string_and_rpar_indices):
+ leaf = LL[idx]
+ lpar_or_rpar_idx = idx - 1 if leaf.type == token.STRING else idx
+ append_leaves(new_line, line, LL[previous_idx + 1 : lpar_or_rpar_idx])
+ if leaf.type == token.STRING:
+ string_leaf = Leaf(token.STRING, LL[idx].value)
+ LL[lpar_or_rpar_idx].remove() # Remove lpar.
+ replace_child(LL[idx], string_leaf)
+ new_line.append(string_leaf)
+ else:
+ LL[lpar_or_rpar_idx].remove() # This is a rpar.
+
+ previous_idx = idx
+
+ # Append the leaves after the last idx:
+ append_leaves(new_line, line, LL[idx + 1 :])
- yield Ok(new_line)
+ return new_line
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,
if isinstance(match_result, Err):
return match_result
- string_idx = match_result.ok()
+ string_indices = match_result.ok()
+ assert len(string_indices) == 1, (
+ f"{self.__class__.__name__} should only find one match at a time, found"
+ f" {len(string_indices)}"
+ )
+ string_idx = string_indices[0]
vresult = self._validate(line, string_idx)
if isinstance(vresult, Err):
return vresult
# 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.
max_string_length = self.line_length - offset
return max_string_length
+ @staticmethod
+ def _prefer_paren_wrap_match(LL: List[Leaf]) -> Optional[int]:
+ """
+ Returns:
+ string_idx such that @LL[string_idx] is equal to our target (i.e.
+ matched) string, if this line matches the "prefer paren wrap" statement
+ requirements listed in the 'Requirements' section of the StringParenWrapper
+ class's docstring.
+ OR
+ None, otherwise.
+ """
+ # The line must start with a string.
+ if LL[0].type != token.STRING:
+ return None
+
+ # If the string is surrounded by commas (or is the first/last child)...
+ prev_sibling = LL[0].prev_sibling
+ next_sibling = LL[0].next_sibling
+ if not prev_sibling and not next_sibling and parent_type(LL[0]) == syms.atom:
+ # If it's an atom string, we need to check the parent atom's siblings.
+ parent = LL[0].parent
+ assert parent is not None # For type checkers.
+ prev_sibling = parent.prev_sibling
+ next_sibling = parent.next_sibling
+ if (not prev_sibling or prev_sibling.type == token.COMMA) and (
+ not next_sibling or next_sibling.type == token.COMMA
+ ):
+ return 0
-class StringSplitter(CustomSplitMapMixin, BaseStringSplitter):
+ return None
+
+
+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))
+
+
+def _toggle_fexpr_quotes(fstring: str, old_quote: str) -> str:
+ """
+ Toggles quotes used in f-string expressions that are `old_quote`.
+
+ f-string expressions can't contain backslashes, so we need to toggle the
+ quotes if the f-string itself will end up using the same quote. We can
+ simply toggle without escaping because, quotes can't be reused in f-string
+ expressions. They will fail to parse.
+
+ NOTE: If PEP 701 is accepted, above statement will no longer be true.
+ Though if quotes can be reused, we can simply reuse them without updates or
+ escaping, once Black figures out how to parse the new grammar.
+ """
+ new_quote = "'" if old_quote == '"' else '"'
+ parts = []
+ previous_index = 0
+ for start, end in iter_fexpr_spans(fstring):
+ parts.append(fstring[previous_index:start])
+ parts.append(fstring[start:end].replace(old_quote, new_quote))
+ previous_index = end
+ parts.append(fstring[previous_index:])
+ return "".join(parts)
+
+
+class StringSplitter(BaseStringSplitter, CustomSplitMapMixin):
"""
StringTransformer that splits "atom" strings (i.e. strings which exist on
lines by themselves).
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"""
- (?<!\{) (?:\{\{)* \{ (?!\{)
- (?:
- [^\{\}]
- | \{\{
- | \}\}
- | (?R)
- )+
- \}
- """
+ MIN_SUBSTR_SIZE: Final = 6
def do_splitter_match(self, line: Line) -> TMatchResult:
LL = line.leaves
+ if self._prefer_paren_wrap_match(LL) is not None:
+ return TErr("Line needs to be wrapped in parens first.")
+
is_valid_index = is_valid_index_factory(LL)
idx = 0
if is_valid_index(idx):
return TErr("This line does not end with a string.")
- return Ok(string_idx)
+ return Ok([string_idx])
- def do_transform(self, line: Line, string_idx: int) -> Iterator[TResult[Line]]:
+ def do_transform(
+ self, line: Line, string_indices: List[int]
+ ) -> Iterator[TResult[Line]]:
LL = line.leaves
+ assert len(string_indices) == 1, (
+ f"{self.__class__.__name__} should only find one match at a time, found"
+ f" {len(string_indices)}"
+ )
+ string_idx = string_indices[0]
QUOTE = LL[string_idx].value[-1]
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
string_op_leaves = self._get_string_operator_leaves(LL)
string_op_leaves_length = (
- sum([len(str(prefix_leaf)) for prefix_leaf in string_op_leaves]) + 1
+ sum(len(str(prefix_leaf)) for prefix_leaf in string_op_leaves) + 1
if string_op_leaves
else 0
)
# --- 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)
+ use_custom_breakpoints
+ and not csplit.has_prefix
+ and (
+ # `next_value == prefix + QUOTE` happens when the custom
+ # split is an empty string.
+ next_value == prefix + QUOTE
+ or next_value != self._normalize_f_string(next_value, 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`
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
assert is_valid_index(max_break_idx)
assert_is_leaf_string(string)
- _fexpr_slices: Optional[List[Tuple[Index, Index]]] = None
-
- 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)
+ _illegal_split_indices = self._get_illegal_split_indices(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:
"""
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.
"""
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) :]
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).
+ StringTransformer that wraps strings in parens and then splits at the LPAR.
Requirements:
All of the requirements listed in BaseStringSplitter's docstring in
OR
* The line is a dictionary key assignment where some valid key is being
assigned the value of some string.
+ OR
+ * The line is an lambda expression and the value is a string.
+ OR
+ * The line starts with an "atom" string that prefers to be wrapped in
+ parens. It's preferred to be wrapped when the string is surrounded by
+ commas (or is the first/last child).
Transformations:
The chosen string is wrapped in parentheses and then split at the LPAR.
changed such that it no longer needs to be given its own line,
StringParenWrapper relies on StringParenStripper to clean up the
parentheses it created.
+
+ For "atom" strings that prefers to be wrapped in parens, it requires
+ StringSplitter to hold the split until the string is wrapped in parens.
"""
def do_splitter_match(self, line: Line) -> TMatchResult:
or self._else_match(LL)
or self._assert_match(LL)
or self._assign_match(LL)
- or self._dict_match(LL)
+ or self._dict_or_lambda_match(LL)
+ or self._prefer_paren_wrap_match(LL)
)
if string_idx is not None:
" resultant line would still be over the specified line"
" length and can't be split further by StringSplitter."
)
- return Ok(string_idx)
+ return Ok([string_idx])
return TErr("This line does not contain any non-atomic strings.")
if parent_type(LL[0]) == syms.assert_stmt and LL[0].value == "assert":
is_valid_index = is_valid_index_factory(LL)
- for (i, leaf) in enumerate(LL):
+ for i, leaf in enumerate(LL):
# We MUST find a comma...
if leaf.type == token.COMMA:
idx = i + 2 if is_empty_par(LL[i + 1]) else i + 1
):
is_valid_index = is_valid_index_factory(LL)
- for (i, leaf) in enumerate(LL):
+ for i, leaf in enumerate(LL):
# We MUST find either an '=' or '+=' symbol...
if leaf.type in [token.EQUAL, token.PLUSEQUAL]:
idx = i + 2 if is_empty_par(LL[i + 1]) else i + 1
return None
@staticmethod
- def _dict_match(LL: List[Leaf]) -> Optional[int]:
+ def _dict_or_lambda_match(LL: List[Leaf]) -> Optional[int]:
"""
Returns:
string_idx such that @LL[string_idx] is equal to our target (i.e.
matched) string, if this line matches the dictionary key assignment
- statement requirements listed in the 'Requirements' section of this
- classes' docstring.
+ statement or lambda expression requirements listed in the
+ 'Requirements' section of this classes' docstring.
OR
None, otherwise.
"""
- # If this line is apart of a dictionary key assignment...
- if syms.dictsetmaker in [parent_type(LL[0]), parent_type(LL[0].parent)]:
+ # If this line is a part of a dictionary key assignment or lambda expression...
+ parent_types = [parent_type(LL[0]), parent_type(LL[0].parent)]
+ if syms.dictsetmaker in parent_types or syms.lambdef in parent_types:
is_valid_index = is_valid_index_factory(LL)
- for (i, leaf) in enumerate(LL):
- # We MUST find a colon...
- if leaf.type == token.COLON:
+ for i, leaf in enumerate(LL):
+ # We MUST find a colon, it can either be dict's or lambda's colon...
+ if leaf.type == token.COLON and i < len(LL) - 1:
idx = i + 2 if is_empty_par(LL[i + 1]) else i + 1
# That colon MUST be followed by a string...
return None
- def do_transform(self, line: Line, string_idx: int) -> Iterator[TResult[Line]]:
+ def do_transform(
+ self, line: Line, string_indices: List[int]
+ ) -> Iterator[TResult[Line]]:
LL = line.leaves
+ assert len(string_indices) == 1, (
+ f"{self.__class__.__name__} should only find one match at a time, found"
+ f" {len(string_indices)}"
+ )
+ string_idx = string_indices[0]
is_valid_index = is_valid_index_factory(LL)
insert_str_child = insert_str_child_factory(LL[string_idx])
f" (left_leaves={left_leaves}, right_leaves={right_leaves})"
)
old_rpar_leaf = right_leaves.pop()
+ elif right_leaves and right_leaves[-1].type == token.RPAR:
+ # Special case for lambda expressions as dict's value, e.g.:
+ # my_dict = {
+ # "key": lambda x: f"formatted: {x},
+ # }
+ # After wrapping the dict's value with parentheses, the string is
+ # followed by a RPAR but its opening bracket is lambda's, not
+ # the string's:
+ # "key": (lambda x: f"formatted: {x}),
+ opening_bracket = right_leaves[-1].opening_bracket
+ if opening_bracket is not None and opening_bracket in left_leaves:
+ index = left_leaves.index(opening_bracket)
+ if (
+ index > 0
+ and index < len(left_leaves) - 1
+ and left_leaves[index - 1].type == token.COLON
+ and left_leaves[index + 1].value == "lambda"
+ ):
+ right_leaves.pop()
append_leaves(string_line, line, right_leaves)
```
"""
- 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,
projects / etc / vim.git / blobdiff