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"""
The MIT License (MIT)
Copyright (c) 2015-present Rapptz
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.
"""
from __future__ import annotations
from typing import Optional
from .errors import UnexpectedQuoteError, InvalidEndOfQuotedStringError, ExpectedClosingQuoteError
# map from opening quotes to closing quotes
_quotes = {
'"': '"',
"‘": "’",
"‚": "‛",
"“": "”",
"„": "‟",
"⹂": "⹂",
"「": "」",
"『": "』",
"〝": "〞",
"﹁": "﹂",
"﹃": "﹄",
"＂": "＂",
"｢": "｣",
"«": "»",
"‹": "›",
"《": "》",
"〈": "〉",
}
_all_quotes = set(_quotes.keys()) | set(_quotes.values())
class StringView:
def __init__(self, buffer: str) -> None:
self.index: int = 0
self.buffer: str = buffer
self.end: int = len(buffer)
self.previous = 0
@property
def current(self) -> Optional[str]:
return None if self.eof else self.buffer[self.index]
@property
def eof(self) -> bool:
return self.index >= self.end
def undo(self) -> None:
self.index = self.previous
def skip_ws(self) -> bool:
pos = 0
while not self.eof:
try:
current = self.buffer[self.index + pos]
if not current.isspace():
break
pos += 1
except IndexError:
break
self.previous = self.index
self.index += pos
return self.previous != self.index
def skip_string(self, string: str) -> bool:
strlen = len(string)
if self.buffer[self.index : self.index + strlen] == string:
self.previous = self.index
self.index += strlen
return True
return False
def read_rest(self) -> str:
result = self.buffer[self.index :]
self.previous = self.index
self.index = self.end
return result
def read(self, n: int) -> str:
result = self.buffer[self.index : self.index + n]
self.previous = self.index
self.index += n
return result
def get(self) -> Optional[str]:
try:
result = self.buffer[self.index + 1]
except IndexError:
result = None
self.previous = self.index
self.index += 1
return result
def get_word(self) -> str:
pos = 0
while not self.eof:
try:
current = self.buffer[self.index + pos]
if current.isspace():
break
pos += 1
except IndexError:
break
self.previous: int = self.index
result = self.buffer[self.index : self.index + pos]
self.index += pos
return result
def get_quoted_word(self) -> Optional[str]:
current = self.current
if current is None:
return None
close_quote = _quotes.get(current)
is_quoted = bool(close_quote)
if is_quoted:
result = []
_escaped_quotes = (current, close_quote)
else:
result = [current]
_escaped_quotes = _all_quotes
while not self.eof:
current = self.get()
if not current:
if is_quoted:
# unexpected EOF
raise ExpectedClosingQuoteError(close_quote)
return ''.join(result)
# currently we accept strings in the format of "hello world"
# to embed a quote inside the string you must escape it: "a \"world\""
if current == '\\':
next_char = self.get()
if not next_char:
# string ends with \ and no character after it
if is_quoted:
# if we're quoted then we're expecting a closing quote
raise ExpectedClosingQuoteError(close_quote)
# if we aren't then we just let it through
return ''.join(result)
if next_char in _escaped_quotes:
# escaped quote
result.append(next_char)
else:
# different escape character, ignore it
self.undo()
result.append(current)
continue
if not is_quoted and current in _all_quotes:
# we aren't quoted
raise UnexpectedQuoteError(current)
# closing quote
if is_quoted and current == close_quote:
next_char = self.get()
valid_eof = not next_char or next_char.isspace()
if not valid_eof:
raise InvalidEndOfQuotedStringError(next_char) # type: ignore # this will always be a string
# we're quoted so it's okay
return ''.join(result)
if current.isspace() and not is_quoted:
# end of word found
return ''.join(result)
result.append(current)
def __repr__(self) -> str:
return f'<StringView pos: {self.index} prev: {self.previous} end: {self.end} eof: {self.eof}>'
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