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#!/usr/bin/env python3
import typing
import re
import io
class Token:
def __init__(self, lineno: int, tpe: str, text: str):
self.tpe = tpe
self.lineno = lineno
self.text = text
def __str__(self):
return f'Token(tpe={self.tpe}, text={self.text})'
class EmptyLineToken(Token):
def __init__(self, lineno: int):
super().__init__(lineno, 'emptyline', '')
class TextToken(Token):
def __init__(self, lineno: int, indent: int, text: str):
super().__init__(lineno, 'text', text)
self.indent = indent
class LogToken(Token):
def __init__(self, lineno: int, text: str):
super().__init__(lineno, 'log', text)
class UsageToken(Token):
def __init__(self, lineno: int, text: str):
super().__init__(lineno, 'usage', text)
class OptionsToken(Token):
def __init__(self, lineno: int, text: str):
super().__init__(lineno, 'options', text)
class OptionToken(Token):
def __init__(self, lineno: int, text: str):
super().__init__(lineno, 'option', text)
def lexer(lines: typing.Iterator[str]):
for lineno, line in enumerate(lines):
line = line.rstrip()
if not line:
yield EmptyLineToken(lineno)
elif re.match('(?:\033\\[\\d+m)?(?:INFO|ERROR)(?:\033\\[0m)?: ', line):
pass
elif re.match('usage: ', line):
yield UsageToken(lineno, line)
elif re.match('options:', line):
yield OptionsToken(lineno, line)
elif re.match('\\s+-', line):
yield OptionToken(lineno, line)
else:
indent = re.search('\\S', line).start()
yield TextToken(lineno, indent, line)
T = typing.TypeVar('T')
class LookAheadIterator(typing.Generic[T]):
def __init__(self, it: typing.Iterator[T]):
self._it = it
self._lookahead_buffer = list()
self._lookahead_index = -1
def lookahead(self):
if self._lookahead_index + 1 == len(self._lookahead_buffer):
try:
ret = next(self._it)
self._lookahead_index += 1
self._lookahead_buffer.append(ret)
return ret
except StopIteration:
return None
else:
self._lookahead_index += 1
return self._lookahead_buffer[self._lookahead_index]
def consume(self):
self._lookahead_buffer = self._lookahead_buffer[self._lookahead_index+1:]
self._lookahead_index = -1
def rollback(self):
self._lookahead_index -= 1
def reset(self):
self._lookahead_index = -1
class SyntaxErrorException(Exception):
pass
class Parser:
def on_usage(self, text: str):
print('<usage/>')
def enter_description(self):
print('<description>')
def exit_description(self):
print('</description>')
def on_paragraph(self, text: str):
print(f'<paragraph>{text}</paragraph>')
def enter_options(self):
print('<options>')
def exit_options(self):
print('</options>')
def enter_option_group(self, name: str):
print(f'<option_group name={name}>')
def exit_option_group(self, name: str):
print(f'</option_group name={name}>')
def on_option(self, option: str, help: str):
print(f'<option name={option}/>')
def parse_help(self, tokens: LookAheadIterator[Token]):
self.parse_usage(tokens)
self.parse_description(tokens)
self.parse_options(tokens)
tokens.reset()
class MatchFailure(Exception):
pass
def parse_usage(self, tokens: LookAheadIterator[Token]):
token = tokens.lookahead()
self.assert_token_tpe('usage', token)
buf = io.StringIO()
buf.write(token.text)
while True:
token = tokens.lookahead()
if token is None:
tokens.consume()
self.on_usage(buf.getvalue())
elif token.tpe == 'text':
buf.write(' ')
buf.write(token.text[token.indent:])
elif token.tpe == 'option':
buf.write(' ')
buf.write(token.text.lstrip())
else:
self.assert_token_tpe('emptyline', token)
tokens.rollback()
self.parse_emptyline(tokens)
self.on_usage(buf.getvalue())
break
def parse_description(self, tokens: LookAheadIterator[Token]):
result = self.parse_paragraph(tokens)
if result is not None:
indent, paragraph = result
self.enter_description()
tokens.consume()
self.on_paragraph(paragraph)
while True:
ret = self.parse_paragraph(tokens)
if ret is None:
self.exit_description()
return
indent, text = ret
tokens.consume()
self.on_paragraph(text)
def parse_options(self, tokens: LookAheadIterator[Token]):
token = tokens.lookahead()
if token.tpe != 'options':
return
else:
self.enter_options()
self.parse_option_group(tokens)
while self.parse_named_option_group(tokens):
pass
self.exit_options()
def parse_option_group(self, tokens: LookAheadIterator[Token]):
while True:
ret = self.parse_option(tokens)
if ret is None:
break
option, help = ret
self.on_option(option, help)
def parse_option(self, tokens: LookAheadIterator[Token]):
token = tokens.lookahead()
if token is not None and token.tpe == 'option':
match = re.match(
'\\s+((?:-[a-zA-Z]|--[-a-zA-Z0-9]+)(?:\\s[^, ]+)?(?:,\\s+--[-a-zA-Z0-9]+(?:\\s[^, ]+)?)?)\\s*',
token.text,
)
if match is None:
tokens.rollback()
return None
option = match.group(1)
buf = io.StringIO()
buf.write(token.text[match.end():])
while True:
token = tokens.lookahead()
if token is None:
tokens.consume()
break
elif token.tpe != 'text':
tokens.rollback()
break
else:
tokens.consume()
if buf.tell() != 0:
buf.write(' ')
buf.write(token.text[token.indent:])
return option, buf.getvalue()
def parse_named_option_group(self, tokens: LookAheadIterator[Token]):
token = tokens.lookahead()
if token is None:
tokens.rollback()
return
elif token.tpe == 'emptyline':
tokens.rollback()
self.parse_emptyline(tokens)
if token.tpe == 'text' and token.indent == 0 and token.text[-1] == ':':
group_name = token.text[:-1]
description = list()
while True:
ret = self.parse_paragraph(tokens)
if ret is None:
break
indent, text = ret
description.append(text)
ret = self.parse_option(tokens)
if ret is None:
tokens.reset()
return
else:
self.enter_option_group(group_name)
for paragraph in description:
self.on_paragraph(paragraph)
option, help = ret
self.on_option(option, help)
tokens.consume()
while True:
ret = self.parse_option(tokens)
if ret is None:
break
option, help = ret
self.on_option(option, help)
tokens.consume()
self.parse_emptyline(tokens)
self.exit_option_group(group_name)
tokens.consume()
return True
else:
tokens.rollback()
return False
@classmethod
def assert_token_tpe(cls, tpe: str, token: Token):
if token.tpe != tpe:
raise SyntaxErrorException(f'Expected: <{tpe}>. Actual: <{token.tpe}>')
def parse_log(self, tokens: LookAheadIterator[Token]):
# TODO: remove me
while True:
token = tokens.lookahead()
if token.tpe == 'log':
tokens.consume()
else:
return
def parse_paragraph(self, tokens: LookAheadIterator[Token]):
buf = io.StringIO()
indent = -1
while True:
token = tokens.lookahead()
if token is None:
tokens.consume()
break
if token.tpe != 'text':
tokens.rollback()
break
new_indent = token.indent
if indent == -1:
indent = new_indent
buf.write(token.text[indent:])
elif new_indent == indent:
buf.write(' ')
buf.write(token.text[indent:])
else:
tokens.rollback()
break
if indent == -1:
return None
else:
token = tokens.lookahead()
if token is not None:
tokens.rollback()
self.parse_emptyline(tokens)
return indent, buf.getvalue()
def parse_emptyline(self, tokens: LookAheadIterator[Token]):
while True:
token = tokens.lookahead()
if token.tpe != 'emptyline':
tokens.rollback()
break
def main():
import sys
stdin = sys.stdin
with open(3, buffering=1) as stdin:
tokens = LookAheadIterator(lexer(stdin))
Parser().parse_help(tokens)
print('epilog starts at line {}'.format(tokens.lookahead().lineno))
if __name__ == '__main__':
main()
|
