def context(self) -> Optional[str]:
"""
A formatted string containing the line of code with the syntax error (or a
non-empty line above it) along with a caret indicating the exact column where
the error occurred.
Return ``None`` if there's no relevant non-empty line to show. (e.g. the file
consists of only blank lines)
"""
displayed_line = self.editor_line
displayed_column = self.editor_column
# we want to avoid displaying a blank line for context. If we're on a blank line
# find the nearest line above us that isn't blank.
while displayed_line >= 1 and not len(
self._lines[displayed_line - 1].strip()):
displayed_line -= 1
displayed_column = len(self._lines[displayed_line - 1])
# only show context if we managed to find a non-empty line
if len(self._lines[displayed_line - 1].strip()):
formatted_source_line = expand_tabs(
self._lines[displayed_line - 1]).rstrip(_NEWLINE_CHARS)
# fmt: off
return (f"{formatted_source_line}\n" +
f"{' ' * (displayed_column - 1)}^")
# fmt: on
else:
return None
def editor_column(self) -> int:
"""
The one-indexed column in the user's editor, assuming tabs expand to 1-8 spaces.
"""
pos_line, pos_column = self.pos
tab_adjusted_column = len(
expand_tabs(self.lines[pos_line - 1][:pos_column]))
# Text editors use a one-indexed column, so we need to add one to our
# zero-indexed column to get a human-readable result.
return tab_adjusted_column + 1
def editor_column(self) -> int:
"""
The expected one-indexed column that's likely to match the behavior of the
user's editor, assuming tabs expand to 1-8 spaces. This is the column number
shown when the syntax error is printed out with `str`.
This assumes single-width characters. However, because python doesn't ship with
a wcwidth function, it's hard to handle this properly without a third-party
dependency.
For a raw zero-indexed character offset without tab expansion, see
:attr:`raw_column`.
"""
prefix_str = self._lines[self.raw_line - 1][:self.raw_column]
tab_adjusted_column = len(expand_tabs(prefix_str))
# Text editors use a one-indexed column, so we need to add one to our
# zero-indexed column to get a human-readable result.
return tab_adjusted_column + 1
def test_expand_tabs(self, input, output) -> None:
self.assertEqual(expand_tabs(input), output)
