structured_data._patterns.mapping_match.dict_pattern_length() - Code Metrics - Inspection of "Make it easier to verify the mapping destructure o..." - mwchase/python-structured-data - Measure and Improve Code Quality continuously with Scrutinizer

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Push — master ( 1324f3...2cb96a )

by Max

created 2018-07-31 18:06 UTC

dict_pattern_length() A

↳ Parent: structured_data._patterns.mapping_match

Complexity

Conditions

Size

Total Lines	4
Code Lines	4

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
cc	2
eloc	4
nop	1
dl	0
loc	4
rs	10
c	0
b	0
f	0

from .._match_failure import MatchFailure
from .compound_match import CompoundMatch


def value_cant_be_smaller(target_match_dict, value_match_dict):
    if len(value_match_dict) < len(target_match_dict):
        raise MatchFailure


class AttrPattern(CompoundMatch, tuple):
    """A matcher that destructures an object using attribute access."""

    __slots__ = ()

    def __new__(*args, **kwargs):
        cls, *args = args
        if args:
            raise ValueError(args)
        return super(AttrPattern, cls).__new__(cls, (tuple(kwargs.items()),))

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

    def destructure(self, value):
        if not self.match_dict:
            return ()
        if isinstance(value, AttrPattern):
            value_cant_be_smaller(self.match_dict, value.match_dict)
            first_match, *remainder = value.match_dict
            return (AttrPattern(**dict(remainder)), first_match[1])

        first_match = self.match_dict[0]
        try:
            return (value, getattr(value, first_match[0]))
        except AttributeError:
            raise MatchFailure


def dict_pattern_length(dp_or_d):
    if isinstance(dp_or_d, DictPattern):
        return len(dp_or_d.match_dict)
    return len(dp_or_d)


def exhaustive_length_must_match(target, value):
    if target.exhaustive and dict_pattern_length(value) != dict_pattern_length(target):
        raise MatchFailure


class DictPattern(CompoundMatch, tuple):
    """A matcher that destructures a dictionary by key."""

    __slots__ = ()

    def __new__(cls, match_dict, *, exhaustive=False):
        return super(DictPattern, cls).__new__(
            cls, (tuple(match_dict.items()), exhaustive)
        )

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

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

    def destructure(self, value):
        exhaustive_length_must_match(self, value)
        if not self.match_dict:
            return ()
        if isinstance(value, DictPattern):
            value_cant_be_smaller(self.match_dict, value.match_dict)
            first_match, *remainder = value.match_dict
            return (DictPattern(dict(remainder)), first_match[1])

        first_match = self.match_dict[0]
        try:
            return (value, value[first_match[0]])
        except KeyError:
            raise MatchFailure


1			from .._match_failure import MatchFailure
2			from .compound_match import CompoundMatch
3
4
5			def value_cant_be_smaller(target_match_dict, value_match_dict):
6			if len(value_match_dict) < len(target_match_dict):
7			raise MatchFailure
8
9
10			class AttrPattern(CompoundMatch, tuple):
11			"""A matcher that destructures an object using attribute access."""
12
13			__slots__ = ()
14
15			def __new__(args, *kwargs):
16			cls, *args = args
17			if args:
18			raise ValueError(args)
19			return super(AttrPattern, cls).__new__(cls, (tuple(kwargs.items()),))
20
21			@property
22			def match_dict(self):
23			return self[0]
24
25			def destructure(self, value):
26			if not self.match_dict:
27			return ()
28			if isinstance(value, AttrPattern):
29			value_cant_be_smaller(self.match_dict, value.match_dict)
30			first_match, *remainder = value.match_dict
31			return (AttrPattern(**dict(remainder)), first_match[1])
			1 ignored issue – show Comprehensibility Best Practice introduced 2018-07-29 15:43 UTC by Report Bug Copy Issue Report The variable `remainder` does not seem to be defined. Loading history...
32			first_match = self.match_dict[0]
33			try:
34			return (value, getattr(value, first_match[0]))
35			except AttributeError:
36			raise MatchFailure
37
38
39			def dict_pattern_length(dp_or_d):
40			if isinstance(dp_or_d, DictPattern):
41			return len(dp_or_d.match_dict)
42			return len(dp_or_d)
43
44
45			def exhaustive_length_must_match(target, value):
46			if target.exhaustive and dict_pattern_length(value) != dict_pattern_length(target):
47			raise MatchFailure
48
49
50			class DictPattern(CompoundMatch, tuple):
51			"""A matcher that destructures a dictionary by key."""
52
53			__slots__ = ()
54
55			def __new__(cls, match_dict, *, exhaustive=False):
56			return super(DictPattern, cls).__new__(
57			cls, (tuple(match_dict.items()), exhaustive)
58			)
59
60			@property
61			def match_dict(self):
62			return self[0]
63
64			@property
65			def exhaustive(self):
66			return self[1]
67
68			def destructure(self, value):
69			exhaustive_length_must_match(self, value)
70			if not self.match_dict:
71			return ()
72			if isinstance(value, DictPattern):
73			value_cant_be_smaller(self.match_dict, value.match_dict)
74			first_match, *remainder = value.match_dict
75			return (DictPattern(dict(remainder)), first_match[1])
			1 ignored issue – show Comprehensibility Best Practice introduced 2018-07-29 15:43 UTC by Report Bug Copy Issue Report The variable `remainder` does not seem to be defined. Loading history...
76			first_match = self.match_dict[0]
77			try:
78			return (value, value[first_match[0]])
79			except KeyError:
80			raise MatchFailure
81

mwchase / python-structured-data

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dict_pattern_length() A

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