simple-specification

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A simple pythonic implementation of the Specification Pattern for Python 3.7 or higher.

Installation

pip install simple-specification

Examples

Creating specification classes to check integer numbers

from simple_specification import Specification


# hardcoded specification
class Odd(Specification):
    def is_satisfied_by(self, candidate: int) -> bool:
        return candidate % 2 != 0


# parametrized specification
class DivisibleBy(Specification):
    def __init__(self, number: int):
        self.number = number

    def is_satisfied_by(self, candidate: int) -> bool:
        return candidate % self.number == 0

Instantiating the specifications

>>> odd = Odd()
>>> even = ~odd
>>> div3 = DivisibleBy(3)
>>> div5 = DivisibleBy(5)

Using specifications - method is_satisfied_by(candidate)

>>> odd.is_satisfied_by(1)
True
>>> odd.is_satisfied_by(2)
False
>>> even.is_satisfied_by(3)
False
>>> even.is_satisfied_by(4)
True
>>> div3.is_satisfied_by(9)
True
>>> div5.is_satisfied_by(12)
False

Composing specifications - operators & and |

>>> # AND
>>> (even & div3).is_satisfied_by(6)
True
>>> (even & div3).is_satisfied_by(9)
False
>>> (even & div3 & div5).is_satisfied_by(30)
True
>>> (even & div3 & div5).is_satisfied_by(36)
False
>>>
>>> # OR
>>> (even | div3).is_satisfied_by(10)
True
>>> (even | div3).is_satisfied_by(15)
True
>>> (even | div3).is_satisfied_by(5)
False

Negating specifications - operator ~

>>> (~odd).is_satisfied_by(2)
True
>>> (~div5).is_satisfied_by(25)
False
>>> (~div5).is_satisfied_by(11)
True
>>> (~(odd | div5)).is_satisfied_by(6)
True
>>> (~(odd | div5)).is_satisfied_by(7)
False

Composing a list of specifications with & - class method Specification.all(specs)

>>> all_spec = Specification.all([~even, div3, div5])
>>> all_spec.is_satisfied_by(15)
True
>>> all_spec.is_satisfied_by(30)
False
>>> all_spec.is_satisfied_by(25)
False
>>> all_spec.is_satisfied_by(6)
False

Composing a list of specifications with | - class method Specification.any(specs)

>>> div15 = DivisibleBy(3) & DivisibleBy(5)
>>> any_spec = Specification.any([div15, even])
>>> any_spec.is_satisfied_by(2)
True
>>> any_spec.is_satisfied_by(15)
True
>>> any_spec.is_satisfied_by(30)
True
>>> any_spec.is_satisfied_by(3)
False
>>> any_spec.is_satisfied_by(5)
False

Release files for simple-specification 0.3

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for simple-specification 0.3
File	Size	Uploaded
simple-specification-0.3.tar.gz	2.6 kB	Sep 30, 2019	Details

Built distribution (wheel)

Table of built distributions (wheels) for simple-specification 0.3
File	Interpreter	ABI	Platform	Reset
simple_specification-0.3-py3-none-any.whl 3.6 kB Sep 30, 2019	Python 3	none	any	Details

Total release size:6.2 kB

Release files / simple-specification-0.3.tar.gz

Download URL	simple-specification-0.3.tar.gz
Size	2.6 kB
Tags	Source
SHA-256 checksum How to use checksums	`1d75783c12479ac1d40072b9976fdd73c26eb4918ded81da2ec03991d0846dc6`
BLAKE2b-256 checksum How to use checksums	`40a7aa5aa306e56fbf4260f4e66bd01b59a1a2023f2d7b1cc9115d4667a950dd`
Upload date	Sep 30, 2019
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/2.0.0 pkginfo/1.5.0.1 requests/2.22.0 setuptools/41.2.0 requests-toolbelt/0.9.1 tqdm/4.36.1 CPython/3.7.3`

Release files / simple_specification-0.3-py3-none-any.whl

Download URL	simple_specification-0.3-py3-none-any.whl
Size	3.6 kB
Tags	Python 3
SHA-256 checksum How to use checksums	`e3e9e098bfcd78bcac75c2fcec906afd0f01b60d2b256edb641885a8125900fd`
BLAKE2b-256 checksum How to use checksums	`e19a8908b5cc0ecf17466526eb3322fb2c42cceee92c798ffbadc0714c9cfd7a`
Upload date	Sep 30, 2019
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/2.0.0 pkginfo/1.5.0.1 requests/2.22.0 setuptools/41.2.0 requests-toolbelt/0.9.1 tqdm/4.36.1 CPython/3.7.3`