X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/3feff21eca0eee4b9fe72d12b506ac273cb5bcd0..e9356c1ff0083aea4416bf1d3e29748634bb4f7f:/src/black/trans.py

diff --git a/src/black/trans.py b/src/black/trans.py
index ec07f5e..daed264 100644
--- a/src/black/trans.py
+++ b/src/black/trans.py
@@ -2,7 +2,6 @@
 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
@@ -12,9 +11,11 @@ from typing import (
     ClassVar,
     Collection,
     Dict,
+    Final,
     Iterable,
     Iterator,
     List,
+    Literal,
     Optional,
     Sequence,
     Set,
@@ -23,16 +24,11 @@ from typing import (
     Union,
 )
 
-if sys.version_info < (3, 8):
-    from typing_extensions import Final, Literal
-else:
-    from typing import Literal, Final
-
 from mypy_extensions import trait
 
 from black.comments import contains_pragma_comment
 from black.lines import Line, append_leaves
-from black.mode import Feature
+from black.mode import Feature, Mode
 from black.nodes import (
     CLOSING_BRACKETS,
     OPENING_BRACKETS,
@@ -48,9 +44,11 @@ from black.nodes import (
 from black.rusty import Err, Ok, Result
 from black.strings import (
     assert_is_leaf_string,
+    count_chars_in_width,
     get_string_prefix,
     has_triple_quotes,
     normalize_string_quotes,
+    str_width,
 )
 from blib2to3.pgen2 import token
 from blib2to3.pytree import Leaf, Node
@@ -63,7 +61,7 @@ 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
@@ -71,6 +69,8 @@ StringID = int
 TResult = Result[T, CannotTransform]  # (T)ransform Result
 TMatchResult = TResult[List[Index]]
 
+SPLIT_SAFE_CHARS = frozenset(["\u3001", "\u3002", "\uff0c"])  # East Asian stops
+
 
 def TErr(err_msg: str) -> Err[CannotTransform]:
     """(T)ransform Err
@@ -81,7 +81,9 @@ def TErr(err_msg: str) -> Err[CannotTransform]:
     return Err(cant_transform)
 
 
-def hug_power_op(line: Line, features: Collection[Feature]) -> Iterator[Line]:
+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.
@@ -199,11 +201,11 @@ class StringTransformer(ABC):
         """
         Returns:
             * 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
+              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 no match could be made.
         """
 
@@ -214,12 +216,12 @@ class StringTransformer(ABC):
         """
         Yields:
             * Ok(new_line) where new_line is the new transformed line.
-                OR
+              OR
             * Err(CannotTransform) if the transformation failed for some reason. The
-            `do_match(...)` template method should usually be used to reject
-            the form of the given Line, but in some cases it is difficult to
-            know whether or not a Line meets the StringTransformer's
-            requirements until the transformation is already midway.
+              `do_match(...)` template method should usually be used to reject
+              the form of the given Line, but in some cases it is difficult to
+              know whether or not a Line meets the StringTransformer's
+              requirements until the transformation is already midway.
 
         Side Effects:
             This method should NOT mutate @line directly, but it MAY mutate the
@@ -228,7 +230,9 @@ class StringTransformer(ABC):
             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.
@@ -327,8 +331,8 @@ class CustomSplitMapMixin:
 
         Returns:
             * A list of the custom splits that are mapped to @string, if any
-            exist.
-                OR
+              exist.
+              OR
             * [], otherwise.
 
         Side Effects:
@@ -357,14 +361,14 @@ class StringMerger(StringTransformer, CustomSplitMapMixin):
     Requirements:
         (A) The line contains adjacent strings such that ALL of the validation checks
         listed in StringMerger._validate_msg(...)'s docstring pass.
-            OR
+        OR
         (B) The line contains a string which uses line continuation backslashes.
 
     Transformations:
         Depending on which of the two requirements above where met, either:
 
         (A) The string group associated with the target string is merged.
-            OR
+        OR
         (B) All line-continuation backslashes are removed from the target string.
 
     Collaborations:
@@ -572,6 +576,12 @@ class StringMerger(StringTransformer, CustomSplitMapMixin):
                 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]
@@ -951,17 +961,20 @@ class BaseStringSplitter(StringTransformer):
 
     Requirements:
         * The target string value is responsible for the line going over the
-        line length limit. It follows that after all of black's other line
-        split methods have been exhausted, this line (or one of the resulting
-        lines after all line splits are performed) would still be over the
-        line_length limit unless we split this string.
-            AND
+          line length limit. It follows that after all of black's other line
+          split methods have been exhausted, this line (or one of the resulting
+          lines after all line splits are performed) would still be over the
+          line_length limit unless we split this string.
+          AND
+
         * The target string is NOT a "pointless" string (i.e. a string that has
-        no parent or siblings).
-            AND
+          no parent or siblings).
+          AND
+
         * The target string is not followed by an inline comment that appears
-        to be a pragma.
-            AND
+          to be a pragma.
+          AND
+
         * The target string is not a multiline (i.e. triple-quote) string.
     """
 
@@ -1013,7 +1026,7 @@ class BaseStringSplitter(StringTransformer):
 
         Returns:
             * Ok(None), if ALL of the requirements are met.
-                OR
+              OR
             * Err(CannotTransform), if ANY of the requirements are NOT met.
         """
         LL = line.leaves
@@ -1154,7 +1167,7 @@ class BaseStringSplitter(StringTransformer):
             # WMA4 the length of the inline comment.
             offset += len(comment_leaf.value)
 
-        max_string_length = self.line_length - offset
+        max_string_length = count_chars_in_width(str(line), self.line_length - offset)
         return max_string_length
 
     @staticmethod
@@ -1172,19 +1185,33 @@ class BaseStringSplitter(StringTransformer):
         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
+        matching_nodes = [
+            syms.listmaker,
+            syms.dictsetmaker,
+            syms.testlist_gexp,
+        ]
+        # If the string is an immediate child of a list/set/tuple literal...
+        if (
+            parent_type(LL[0]) in matching_nodes
+            or parent_type(LL[0].parent) in matching_nodes
         ):
-            return 0
+            # And 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
 
         return None
 
@@ -1240,6 +1267,30 @@ 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
@@ -1247,9 +1298,9 @@ class StringSplitter(BaseStringSplitter, CustomSplitMapMixin):
 
     Requirements:
         * The line consists ONLY of a single string (possibly prefixed by a
-        string operator [e.g. '+' or '==']), MAYBE a string trailer, and MAYBE
-        a trailing comma.
-            AND
+          string operator [e.g. '+' or '==']), MAYBE a string trailer, and MAYBE
+          a trailing comma.
+          AND
         * All of the requirements listed in BaseStringSplitter's docstring.
 
     Transformations:
@@ -1385,11 +1436,13 @@ class StringSplitter(BaseStringSplitter, CustomSplitMapMixin):
             is_valid_index(string_idx + 1) and LL[string_idx + 1].type == token.COMMA
         )
 
-        def max_last_string() -> int:
+        def max_last_string_column() -> int:
             """
             Returns:
-                The max allowed length of the string value used for the last
-                line we will construct.
+                The max allowed width of the string value used for the last
+                line we will construct.  Note that this value means the width
+                rather than the number of characters (e.g., many East Asian
+                characters expand to two columns).
             """
             result = self.line_length
             result -= line.depth * 4
@@ -1397,14 +1450,14 @@ class StringSplitter(BaseStringSplitter, CustomSplitMapMixin):
             result -= string_op_leaves_length
             return result
 
-        # --- Calculate Max Break Index (for string value)
+        # --- Calculate Max Break Width (for string value)
         # We start with the line length limit
-        max_break_idx = self.line_length
+        max_break_width = self.line_length
         # The last index of a string of length N is N-1.
-        max_break_idx -= 1
+        max_break_width -= 1
         # Leading whitespace is not present in the string value (e.g. Leaf.value).
-        max_break_idx -= line.depth * 4
-        if max_break_idx < 0:
+        max_break_width -= line.depth * 4
+        if max_break_width < 0:
             yield TErr(
                 f"Unable to split {LL[string_idx].value} at such high of a line depth:"
                 f" {line.depth}"
@@ -1417,7 +1470,7 @@ class StringSplitter(BaseStringSplitter, CustomSplitMapMixin):
         # line limit.
         use_custom_breakpoints = bool(
             custom_splits
-            and all(csplit.break_idx <= max_break_idx for csplit in custom_splits)
+            and all(csplit.break_idx <= max_break_width for csplit in custom_splits)
         )
 
         # Temporary storage for the remaining chunk of the string line that
@@ -1433,7 +1486,7 @@ class StringSplitter(BaseStringSplitter, CustomSplitMapMixin):
             if use_custom_breakpoints:
                 return len(custom_splits) > 1
             else:
-                return len(rest_value) > max_last_string()
+                return str_width(rest_value) > max_last_string_column()
 
         string_line_results: List[Ok[Line]] = []
         while more_splits_should_be_made():
@@ -1443,7 +1496,10 @@ class StringSplitter(BaseStringSplitter, CustomSplitMapMixin):
                 break_idx = csplit.break_idx
             else:
                 # Algorithmic Split (automatic)
-                max_bidx = max_break_idx - string_op_leaves_length
+                max_bidx = (
+                    count_chars_in_width(rest_value, max_break_width)
+                    - string_op_leaves_length
+                )
                 maybe_break_idx = self._get_break_idx(rest_value, max_bidx)
                 if maybe_break_idx is None:
                     # If we are unable to algorithmically determine a good split
@@ -1540,7 +1596,7 @@ class StringSplitter(BaseStringSplitter, CustomSplitMapMixin):
 
             # Try to fit them all on the same line with the last substring...
             if (
-                len(temp_value) <= max_last_string()
+                str_width(temp_value) <= max_last_string_column()
                 or LL[string_idx + 1].type == token.COMMA
             ):
                 last_line.append(rest_leaf)
@@ -1660,6 +1716,7 @@ class StringSplitter(BaseStringSplitter, CustomSplitMapMixin):
                 section of this classes' docstring would be be met by returning @i.
             """
             is_space = string[i] == " "
+            is_split_safe = is_valid_index(i - 1) and string[i - 1] in SPLIT_SAFE_CHARS
 
             is_not_escaped = True
             j = i - 1
@@ -1672,7 +1729,7 @@ class StringSplitter(BaseStringSplitter, CustomSplitMapMixin):
                 and len(string[:i]) >= self.MIN_SUBSTR_SIZE
             )
             return (
-                is_space
+                (is_space or is_split_safe)
                 and is_not_escaped
                 and is_big_enough
                 and not breaks_unsplittable_expression(i)
@@ -1750,25 +1807,26 @@ class StringParenWrapper(BaseStringSplitter, CustomSplitMapMixin):
         addition to the requirements listed below:
 
         * The line is a return/yield statement, which returns/yields a string.
-            OR
+          OR
         * The line is part of a ternary expression (e.g. `x = y if cond else
-        z`) such that the line starts with `else <string>`, where <string> is
-        some string.
-            OR
+          z`) such that the line starts with `else <string>`, where <string> is
+          some string.
+          OR
         * The line is an assert statement, which ends with a string.
-            OR
+          OR
         * The line is an assignment statement (e.g. `x = <string>` or `x +=
-        <string>`) such that the variable is being assigned the value of some
-        string.
-            OR
+          <string>`) such that the variable is being assigned the value of some
+          string.
+          OR
         * The line is a dictionary key assignment where some valid key is being
-        assigned the value of some string.
-            OR
+          assigned the value of some string.
+          OR
         * The line is an lambda expression and the value is a string.
-            OR
+          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).
+          parens. It's preferred to be wrapped when it's is an immediate child of
+          a list/set/tuple literal, AND 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.
@@ -1817,11 +1875,13 @@ class StringParenWrapper(BaseStringSplitter, CustomSplitMapMixin):
 
         if string_idx is not None:
             string_value = line.leaves[string_idx].value
-            # If the string has no spaces...
-            if " " not in string_value:
+            # If the string has neither spaces nor East Asian stops...
+            if not any(
+                char == " " or char in SPLIT_SAFE_CHARS for char in string_value
+            ):
                 # And will still violate the line length limit when split...
-                max_string_length = self.line_length - ((line.depth + 1) * 4)
-                if len(string_value) > max_string_length:
+                max_string_width = self.line_length - ((line.depth + 1) * 4)
+                if str_width(string_value) > max_string_width:
                     # And has no associated custom splits...
                     if not self.has_custom_splits(string_value):
                         # Then we should NOT put this string on its own line.
@@ -2212,7 +2272,7 @@ class StringParser:
         Returns:
             The index directly after the last leaf which is apart of the string
             trailer, if a "trailer" exists.
-                OR
+            OR
             @string_idx + 1, if no string "trailer" exists.
         """
         assert leaves[string_idx].type == token.STRING
@@ -2226,11 +2286,11 @@ class StringParser:
         """
         Pre-conditions:
             * On the first call to this function, @leaf MUST be the leaf that
-            was directly after the string leaf in question (e.g. if our target
-            string is `line.leaves[i]` then the first call to this method must
-            be `line.leaves[i + 1]`).
+              was directly after the string leaf in question (e.g. if our target
+              string is `line.leaves[i]` then the first call to this method must
+              be `line.leaves[i + 1]`).
             * On the next call to this function, the leaf parameter passed in
-            MUST be the leaf directly following @leaf.
+              MUST be the leaf directly following @leaf.
 
         Returns:
             True iff @leaf is apart of the string's trailer.