+ @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
+
+ 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
+ ):
+ # 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
+
+
+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)
+
projects / etc / vim.git / blobdiff