98 lines
3.2 KiB
Python
98 lines
3.2 KiB
Python
from emis_funky_funktions import *
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from dataclasses import dataclass
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from enum import auto, IntEnum
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from operator import eq, is_not
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from re import Pattern
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from typing import Collection, Tuple, List, NewType
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@dataclass(frozen=True)
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class Lexeme(Generic[B]):
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token: B
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matched_string: str
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line: int
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col_start: int
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col_end: int
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def __repr__(self):
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return f'[{repr(self.token)}: {repr(self.matched_string)}]@({self.line}, {self.col_start}-{self.col_end})'
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def try_lex1(regex: Pattern[str], tok: A, input: str, line_no: int, col_no: int) -> Option[Tuple[Lexeme[A], str]]:
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"""
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Attempt to recognize a single token against a full input string
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If successful, returns the token provided as an argument, the part of the input which
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matched, and the rest of the input. Otherwise, returns `None`
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>>> try_lex1(compile(r'\d+'), "NUMBER", "123abc", 1, 1)
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Some((['NUMBER': '123']@(1, 1-4), 'abc'))
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>>> try_lex1(compile(r'\d+'), "NUMBER", "abc123", 1, 1) is None
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True
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"""
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match regex.match(input):
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case None:
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return None
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case match:
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assert match is not None
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return Some((Lexeme(tok, match.group(), line_no, col_no, col_no + match.end()), input[match.end():]))
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def tokenize(
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lex_table: Collection[Tuple[Pattern[str], A]],
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drop_tokens: Collection[A],
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input: str
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) -> Result[List[Lexeme[A]], str]:
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"""
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Attempt to lex an entire input string.
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Will be lexed into `Tok`s according to `lex_table`. Tokens earlier on in the list
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should be regarded as higher priority, even if a match lower on the list also matches.
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Any tokens in the `drop_tokens` list will be dropped from the output.
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If the lexer is unable to match the input string with any of the tokens, then an `Err`
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is returned containing the section of the input that failed to match.
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>>> tokenize(LEX_TABLE, [Tok.Whitespace], 'Clauses: \\n!man(x5) person') #doctest: +NORMALIZE_WHITESPACE
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Ok([[ClausesSection: 'Clauses:']@(1, 1-9), [Newline: '\\n']@(1, 10-11),
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[Negate: '!']@(2, 1-2), [Identifier: 'man']@(2, 2-5), [OpenP: '(']@(2, 5-6),
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[Identifier: 'x5']@(2, 6-8), [CloseP: ')']@(2, 8-9),
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[Identifier: 'person']@(2, 10-16)])
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>>> tokenize(LEX_TABLE, [Tok.Whitespace], 'Clauses: \\n🍆 !man(x5)')
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Err('🍆 !man(x5)')
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"""
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def inner(input: str, line_no: int, col_no: int, prefix: List[Lexeme[A]]) -> Result[List[Lexeme[A]], str]:
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if len(input):
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try:
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lexeme, rest_input = next(
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unwrap_opt(maybe_lexeme)
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for maybe_lexeme in (
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try_lex1(regex, tok, input, line_no, col_no)
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for (regex, tok) in lex_table
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)
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if isinstance(maybe_lexeme, Some)
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)
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except StopIteration:
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return Err(input)
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if lexeme.token not in drop_tokens:
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prefix.append(lexeme)
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newline_count = len(list(filter(p(eq, '\n'), lexeme.matched_string)))
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new_col_no = (
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len(lexeme.matched_string) - lexeme.matched_string.rfind('\n')
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if newline_count else
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col_no + len(lexeme.matched_string)
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)
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return inner(rest_input, line_no+newline_count, new_col_no, prefix)
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else:
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return Ok(prefix)
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return inner(input, 1, 1, [])
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if __name__ == '__main__':
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# print(tokenize(open('sample.cnf').read()))
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import doctest
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from re import compile
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from grammar import Tok, LEX_TABLE
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doctest.testmod() |