56 lines
1.8 KiB
Python
56 lines
1.8 KiB
Python
from emis_funky_funktions import *
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from typing import Collection, Mapping, Sequence, Tuple, TypeAlias
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from parse.comb_parse import Parser
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from ir.patterns import Pattern, NamePattern, IgnorePattern, IntPattern, SPattern
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from parse.lex import Lexeme, tokenize
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from enum import auto, IntEnum
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import re
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class PatTok(IntEnum):
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"""
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All possible tokens used in the grammar
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"""
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Whitespace = auto()
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Number = auto()
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Succ = auto()
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Underscore = auto()
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Name = auto()
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Eof = auto()
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def __repr__(self):
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return self._name_
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PATTERN_LEX_TABLE: Collection[Tuple[re.Pattern[str], PatTok]] = [
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(re.compile(r"\s+"), PatTok.Whitespace),
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(re.compile(r"\d+"), PatTok.Number),
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(re.compile(r"S"), PatTok.Succ),
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(re.compile(r"_"), PatTok.Underscore),
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(re.compile(r"\w+"), PatTok.Name),
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]
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# P := int
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# P := name
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# P := underscore
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# P := S <P>
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parse_int: Parser[Pattern, PatTok] = Parser.token(PatTok.Number).map(Lexeme.get_match).map(int).map(IntPattern)
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parse_name: Parser[Pattern, PatTok] = Parser.token(PatTok.Name).map(Lexeme.get_match).map(p(NamePattern))
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parse_ignore: Parser[Pattern, PatTok] = Parser.token(PatTok.Underscore).map(lambda _: IgnorePattern())
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parse_succ: Parser[Pattern, PatTok] = Parser.token(PatTok.Succ).map(k(SPattern)).fapply(Parser.lazy(lambda: parse_P)) #type: ignore
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parse_P: Parser[Pattern, PatTok] = parse_int.or_(parse_name, parse_ignore, parse_succ)
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parse_pattern = parse_P.seq_ignore_tok(PatTok.Eof)
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def lex_and_parse_pattern(input: str) -> Result[Pattern, str | Mapping[Lexeme[PatTok], Collection[PatTok]]]:
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match tokenize(PATTERN_LEX_TABLE, [PatTok.Whitespace], PatTok.Eof, input):
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case Ok(lexemes):
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match parse_pattern.parse_(lexemes):
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case Ok(pattern): # Imagine having a good type system
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return Ok(pattern)
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case Err(e):
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return Err(e)
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case Err(remainder):
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return Err(remainder)
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raise Exception('Unreachable') |