41 行
1.4 KiB
Python
41 行
1.4 KiB
Python
from anonstream.control.spec import Spec, NoParse, Ambiguous, Parsed
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from anonstream.control.spec.utils import get_item, startswith
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class Str(Spec):
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def __init__(self, directives):
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self.directives = directives
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def consume(self, words, index):
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word = get_item(index, words)
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candidates = tuple(filter(
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lambda directive: startswith(directive, word),
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self.directives,
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))
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try:
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directive = candidates[0]
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except IndexError as e:
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if word is None:
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reason = f'incomplete: expected one of {set(self.directives)}'
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else:
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reason = (
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f'bad word at position {index}: '
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f'expected one of {set(self.directives)}, found {word!r}'
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)
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raise NoParse(reason) from e
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else:
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if len(candidates) > 1:
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raise Ambiguous(
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f'bad word at position {index}: cannot unambiguously '
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f'match {word!r} against {set(self.directives)}'
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)
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return self.directives[directive], 1, []
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class End(Spec):
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def __init__(self, fn):
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self.fn = fn
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def consume(self, words, index):
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if len(words) <= index:
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raise Parsed(self.fn)
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raise NoParse(f'garbage at position {index}: {words[index:]!r}')
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