LibCST/libcst/_exceptions.py
Jennifer Taylor 3dec7be6ef Export things from libcst's base__init__.py
Go through and clean up where we export things from in the top level
directories. This is the first pass at cleaning up the public API. In
this diff I clean up all top-level exports that were coming out of .py
files and instead export them from libcst's base module itself.

I also didn't export a few of the things defined in newly underscored
files because they were only used internally.
2019-07-26 12:48:22 -07:00

84 lines
2.6 KiB
Python

# Copyright (c) Facebook, Inc. and its affiliates.
#
# This source code is licensed under the MIT license found in the
# LICENSE file in the root directory of this source tree.
# pyre-strict
from typing import Iterable, Optional, Sequence, Tuple
from libcst._tabs import expand_tabs
_EOF_STR: str = "end of file (EOF)"
_NEWLINE_CHARS: str = "\r\n"
class ParserSyntaxError(Exception):
"""
Contains error information about the parser tree.
"""
def __init__(
self,
message: str,
encountered: Optional[str], # None means EOF
expected: Optional[Iterable[str]], # None means EOF
pos: Tuple[int, int], # (one-indexed line, zero-indexed column)
lines: Sequence[str], # source code, used to generate a human-readable output
) -> None:
self.message = message
self.encountered = encountered
self.expected = expected
self.pos = pos
self.lines = lines
# Make pickling this error work
super(ParserSyntaxError, self).__init__(
message, encountered, expected, pos, lines
)
def __str__(self) -> str:
"""
A human-readable error message of where the syntax error is in their code.
"""
if self.encountered is not None:
encountered_str = repr(self.encountered)
else:
encountered_str = _EOF_STR
if self.expected is not None:
expected_str = f"one of {repr(list(self.expected))}"
else:
expected_str = _EOF_STR
pos_line, pos_column = self.pos
editor_line = self.editor_line
editor_column = self.editor_column
return (
f"Syntax Error: {self.message} @ {editor_line}:{editor_column}.\n"
+ f"Encountered {encountered_str}, but expected {expected_str}.\n\n"
+ f"{expand_tabs(self.lines[pos_line - 1]).rstrip(_NEWLINE_CHARS)}\n"
+ f"{' ' * (editor_column - 1)}^"
)
@property
def editor_line(self) -> int:
"""
The one-indexed line in the user's editor.
"""
return self.pos[0] # the line in pos is already one-indexed.
@property
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
class MetadataException(Exception):
pass