advent-2022-python/advent/parser/parser.py
Ruediger Ludwig a355de5d8b Initial
2022-11-30 19:39:52 +01:00

359 lines
11 KiB
Python

from __future__ import annotations
from dataclasses import dataclass
from functools import reduce
from itertools import chain
from typing import Any, Callable, Generic, Self, TypeVar, overload
import unicodedata
from .result import Result
T = TypeVar('T')
T1 = TypeVar('T1')
T2 = TypeVar('T2')
T3 = TypeVar('T3')
T4 = TypeVar('T4')
T5 = TypeVar('T5')
TR = TypeVar('TR')
@dataclass(slots=True, frozen=True)
class ParserInput:
input: str
start: int
def step(self, count: int = 1) -> tuple[Self, str]:
assert count > 0
if self.start + count > len(self.input):
raise Exception("Not enough chars left in string")
return ParserInput(self.input, self.start
+ count), self.input[self.start:self.start + count]
def is_eof(self) -> bool:
return self.start >= len(self.input)
def __repr__(self) -> str:
if self.start == 0:
return f'->[{self.input}]'
if self.start >= len(self.input):
return f'{self.input}'
if self.start < 3:
return f'{self.input[0:self.start-1]}->[{self.input[self.start:]}]'
return f'{self.input[self.start-3:self.start-1]}->[{self.input[self.start:]}]'
ParserResult = Result[tuple[ParserInput, T]]
ParserFunc = Callable[[ParserInput], ParserResult[T]]
class P(Generic[T]):
def __init__(self, func: ParserFunc[T]):
self.func = func
def parse(self, s: str, i: int = 0) -> Result[T]:
result = self.func(ParserInput(s, i))
return result.fmap(lambda pr: pr[1])
@staticmethod
def pure(value: T) -> P[T]:
return P(lambda parserPos: Result.of((parserPos, value)))
@staticmethod
def fail(text: str) -> P[Any]:
return P(lambda pp: Result.fail(f'@: {pp}\ntext: {text}'))
@staticmethod
def _fix(p1: Callable[[P[Any]], P[T]]) -> P[T]:
""" Not really nice helper function, but it works"""
return [p._forward(q.func) for p in [P(None)] for q in [p1(p)]][0] # type: ignore
def _forward(self, func: ParserFunc[T]) -> Self:
self.func = func
return self
def bind(self, bind_func: Callable[[T], P[TR]]) -> P[TR]:
def inner(x: tuple[ParserInput, T]):
parserPos, v = x
return bind_func(v).func(parserPos)
return P(lambda parserPos: self.func(parserPos).bind(inner))
def fmap(self, map_func: Callable[[T], TR]) -> P[TR]:
def inner(x: tuple[ParserInput, T]):
parserPos, v = x
return (parserPos, map_func(v))
return P(lambda parserPos: self.func(parserPos).fmap(inner))
def safe_fmap(self, map_func: Callable[[T], TR]) -> P[TR]:
def inner(value: T) -> P[TR]:
try:
return P.pure(map_func(value))
except Exception as e:
return P.fail(f'Failed with {e}')
return self.bind(inner)
def replace(self, value: TR) -> P[TR]:
return self.fmap(lambda _: value)
def unit(self) -> P[tuple[()]]:
return self.fmap(lambda _: ())
def apply(self, p2: P[Callable[[T], TR]]) -> P[TR]:
return self.bind(lambda x: p2.bind(lambda y: P.pure(y(x))))
def between(self, pre: P[Any], post: P[Any]) -> P[T]:
return P.map3(pre, self, post, lambda _1, v, _2: v)
def surround(self, other: P[Any]) -> P[T]:
return P.map3(other, self, other, lambda _1, v, _2: v)
def some(self) -> P[list[T]]:
return P._fix(lambda p: self.bind(
lambda x: P.either(p, P.pure([])).fmap(lambda ys: [x] + ys)))
def many(self) -> P[list[T]]:
return P.either(self.some(), P.pure([]))
def satisfies(self, pred: Callable[[T], bool], failtext: str) -> P[T]:
return self.bind(lambda v: P.pure(v) if pred(
v) else P.fail(f'Does not satisfy: {failtext}'))
def optional(self) -> P[T | None]:
return P.either(self, P.pure(None))
def sep_by(self, sep: P[Any]) -> P[list[T]]:
return P.map2(self, P.snd(sep, self).many(), lambda f, r: [f] + r)
@staticmethod
def snd(p1: P[Any], p2: P[T2]) -> P[T2]:
return p1.bind(lambda _: p2)
@staticmethod
def fst(p1: P[T1], p2: P[Any]) -> P[T1]:
return P.map2(p1, p2, lambda v1, _: v1)
@staticmethod
def no_match(p: P[Any], failtext: str) -> P[tuple[()]]:
def inner(pp: ParserInput) -> ParserResult[tuple[()]]:
result = p.func(pp)
if result.is_fail():
return Result.of((pp, ()))
else:
return Result.fail(failtext)
return P(inner)
@ staticmethod
def map2(p1: P[T1], p2: P[T2], func: Callable[[T1, T2], TR]) -> P[TR]:
return p1.bind(lambda v1: p2.fmap(lambda v2: func(v1, v2)))
@ staticmethod
def map3(p1: P[T1], p2: P[T2], p3: P[T3], func: Callable[[T1, T2, T3], TR]) -> P[TR]:
return p1.bind(
lambda v1: p2.bind(
lambda v2: p3.fmap(
lambda v3: func(v1, v2, v3))))
@ staticmethod
def map4(p1: P[T1], p2: P[T2], p3: P[T3], p4: P[T4],
func: Callable[[T1, T2, T3, T4], TR]) -> P[TR]:
return p1.bind(
lambda v1: p2.bind(
lambda v2: p3.bind(
lambda v3: p4.fmap(
lambda v4: func(v1, v2, v3, v4)))))
@ staticmethod
def map5(p1: P[T1], p2: P[T2], p3: P[T3], p4: P[T4], p5: P[T5],
func: Callable[[T1, T2, T3, T4, T5], TR]) -> P[TR]:
return p1.bind(
lambda v1: p2.bind(
lambda v2: p3.bind(
lambda v3: p4.bind(
lambda v4: p5.fmap(
lambda v5: func(v1, v2, v3, v4, v5))))))
@ staticmethod
@ overload
def seq(p1: P[T1], p2: P[T2], /) -> P[tuple[T1, T2]]:
...
@ staticmethod
@ overload
def seq(p1: P[T1], p2: P[T2], p3: P[T3], /) -> P[tuple[T1, T2, T3]]:
...
@ staticmethod
@ overload
def seq(p1: P[T1], p2: P[T2], p3: P[T3], p4: P[T4], /) -> P[tuple[T1, T2, T3, T4]]:
...
@ staticmethod
@ overload
def seq(p1: P[T1], p2: P[T2], p3: P[T3], p4: P[T4],
p5: P[T5], /) -> P[tuple[T1, T2, T3, T4, T5]]:
...
@ staticmethod
def seq(*ps: P[Any]) -> P[tuple[Any, ...]]:
return reduce(lambda p, x: x.bind(
lambda a: p.fmap(lambda b: chain([a], b))),
list(ps)[::-1], P.pure(iter([]))).fmap(tuple)
@ staticmethod
@ overload
def sep_seq(p1: P[T1], p2: P[T2], /, *, sep: P[Any]) -> P[tuple[T1, T2]]:
...
@ staticmethod
@ overload
def sep_seq(p1: P[T1], p2: P[T2], p3: P[T3], /, *, sep: P[Any]) -> P[tuple[T1, T2, T3]]:
...
@ staticmethod
@ overload
def sep_seq(p1: P[T1], p2: P[T2], p3: P[T3], p4: P[T4], /,
*, sep: P[Any]) -> P[tuple[T1, T2, T3, T4]]:
...
@ staticmethod
@ overload
def sep_seq(p1: P[T1], p2: P[T2], p3: P[T3], p4: P[T4],
p5: P[T5], /, *, sep: P[Any]) -> P[tuple[T1, T2, T3, T4, T5]]:
...
@ staticmethod
def sep_seq(*ps: P[Any], sep: P[Any]) -> P[tuple[Any, ...]]:
first, *rest = list(ps)
return P.map2(first,
reduce(lambda p, x: P.snd(sep, x.bind(
lambda a: p.fmap(lambda b: chain([a], b)))),
rest[::-1], P.pure(iter([]))),
lambda f, r: (f,) + tuple(r))
@ staticmethod
def either(p1: P[T1], p2: P[T2], /) -> P[T1 | T2]:
def inner(parserPos: ParserInput):
result = p1.func(parserPos)
return result if result.is_ok() else p2.func(parserPos)
return P(inner)
@ staticmethod
@ overload
def choice(p1: P[T1], p2: P[T2], p3: P[T3], /) -> P[T1 | T2 | T3]:
...
@ staticmethod
@ overload
def choice(p1: P[T1], p2: P[T2], p3: P[T3], p4: P[T4], /) -> P[T1 | T2 | T3 | T4]:
...
@ staticmethod
@ overload
def choice(p1: P[T1], p2: P[T2], p3: P[T3], p4: P[T4],
p5: P[T5], /) -> P[T1 | T2 | T3 | T4 | T5]:
...
@ staticmethod
def choice(*ps: P[Any]) -> P[Any]:
return reduce(P.either, ps, P.fail('No Choice matched'))
@ staticmethod
def choice_same(*ps: P[T]) -> P[T]:
return P.choice(*ps)
@ staticmethod
def any_char() -> P[str]:
return P(lambda pp: Result.of(pp.step()) if not pp.is_eof()
else Result.fail('At EOF'))
@ staticmethod
def eof() -> P[tuple[()]]:
return P.no_match(P.any_char(), 'Not at eof')
@ staticmethod
def is_char(cmp: str) -> P[str]:
return P.any_char().satisfies(lambda c: c == cmp, f'match {cmp}')
@staticmethod
def is_not_char(s: str) -> P[tuple[()]]:
return P.no_match(P.is_char(s), f'Did match {s}')
@ staticmethod
def char_by_func(cmp: Callable[[str], bool], failtext: str) -> P[str]:
return P.any_char().satisfies(cmp, failtext)
@ staticmethod
def string(s: str) -> P[str]:
return P.seq(*map(P.is_char, s)).replace(s)
@ staticmethod
def one_of(s: str) -> P[str]:
return P.char_by_func(lambda c: c in s, f'one of {s}')
@ staticmethod
def any_decimal() -> P[str]:
return P.char_by_func(lambda c: c.isdecimal(), 'decimal')
@ staticmethod
def is_decimal(num: int) -> P[str]:
return P.any_decimal().bind(
lambda c: P.pure(c) if unicodedata.decimal(c) == num else P.fail(f'Not {num}'))
@ staticmethod
def is_not_decimal(num: int) -> P[str]:
return P.any_decimal().bind(
lambda c: P.pure(c) if unicodedata.decimal(c) != num else P.fail(f'Is {num}'))
@ staticmethod
def lower() -> P[str]:
return P.char_by_func(lambda c: c.islower(), 'lower')
@ staticmethod
def upper() -> P[str]:
return P.char_by_func(lambda c: c.isupper(), 'upper')
@ staticmethod
def joined(p1: P[str]) -> P[str]:
return p1.many().fmap(lambda cs: ''.join(cs))
@ staticmethod
def space() -> P[str]:
return P.char_by_func(lambda c: c.isspace(), 'space')
@ staticmethod
def unsigned() -> P[int]:
return P.either(P.fst(P.is_decimal(0), P.no_match(P.any_decimal(), 'starting Zero')),
P.map2(P.is_not_decimal(0), P.any_decimal().many(),
lambda f, s: f + ''.join(s))
).fmap(int)
@ staticmethod
def signed() -> P[int]:
return P.map2(P.one_of('+-').optional(), P.unsigned(),
lambda sign, num: num if sign != '-' else -num)
def in_parens(self) -> P[T]:
return self.between(P.is_char('('), P.is_char(')'))
def in_angles(self) -> P[T]:
return self.between(P.is_char('<'), P.is_char('>'))
def in_brackets(self) -> P[T]:
return self.between(P.is_char('['), P.is_char(']'))
def in_curleys(self) -> P[T]:
return self.between(P.is_char('{'), P.is_char('}'))
def trim_left(self) -> P[T]:
return P.snd(WHITE_SPACE, self)
def trim_right(self) -> P[T]:
return P.fst(self, WHITE_SPACE)
def trim(self) -> P[T]:
return self.surround(WHITE_SPACE)
WHITE_SPACE: P[tuple[()]] = P.space().many().unit()
SEP_SPACE: P[tuple[()]] = P.space().some().unit()