structured_data._patterns.guard

Complexity

Total Complexity

13

Size/Duplication

Total Lines	49
Duplicated Lines	0 %

Importance

Changes

0

8 Methods

Rating	Name	Duplication	Size	Complexity
A	Guard.guard()	0	3	1
A	AsGuard.guard()	0	3	1
A	AsGuard.__new__()	0	2	1
A	AsGuard.destructure()	0	6	3
A	Guard.__getitem__()	0	2	1
A	AsGuard.structure()	0	3	1
A	Guard.__new__()	0	4	2
A	Guard.destructure()	0	4	3

from .._match_failure import MatchFailure
from .basic_patterns import DISCARD
from .compound_match import CompoundMatch


class Guard(CompoundMatch, tuple):

    __slots__ = ()

    def __new__(cls, guard, structure=DISCARD):
        if structure is not DISCARD:
            return AsGuard(guard, structure)
        return super().__new__(cls, (guard,))

    def __getitem__(self, key):
        return Guard(self.guard, key)

    @property
    def guard(self):
        return tuple.__getitem__(self, 0)

    def destructure(self, value):
        if value is self or self.guard(value):
            return ()
        raise MatchFailure


class AsGuard(CompoundMatch, tuple):

    __slots__ = ()

    def __new__(cls, guard, structure):
        return super().__new__(cls, (guard, structure))

    @property
    def guard(self):
        return self[0]

    @property
    def structure(self):
        return self[1]

    def destructure(self, value):
        if value is self:
            return (self.structure,)
        if self.guard(value):
            return (value,)
        raise MatchFailure