Skip to main content
Help us improve PyPI by participating in user testing. All experience levels needed!

tri.token provides enriched enum functionality

Project description


tri.token provides enriched enum functionality. tri.token enum structures are declared using:

- TokenAttribute: overridable attribute definitions with support for dynamic values.
- Token: holds TokenAttributes objects.
- TokenContainer: holds Token objects.

In other words: a Token is an enum which has TokenInstance members. Token instances are declared within TokenContainer(s).

Basic usage

.. code:: python

from tri.token import Token, TokenAttribute, TokenContainer, PRESENT

class Taste(Token):
name = TokenAttribute()
display_name = TokenAttribute(value=lambda **kwargs: kwargs['name'].upper() + '!!')
opinion = TokenAttribute()

class Tastes(TokenContainer):
vanilla = Taste()
pecan_nut = Taste(display_name="pecan nutz", opinion="Tasty")

# A TokenContainer is a collection of Token objects.
assert Tastes.vanilla in Tastes

# The order of Token objects in a TokenContainer is by order of declaration.
assert list(Tastes) == [Tastes.vanilla, Tastes.pecan_nut]
assert list(Tastes) != [Tastes.pecan_nut, Tastes.vanilla]

# Magic for 'name' TokenAttribute. It is set automatically from the token declaration within it's container.
assert == "vanilla"

# A TokenAttribute will have a None value if not set during Token instantiation.
assert Tastes.vanilla.opinion is None

# A TokenAttribute can have a dynamic value, derived from the invocation to the callable
# set as 'value' in the TokenAttribute definition
# (see declaration of 'display_name' TokenAttribute further up in the code).

# The real value of the token attribute will be the return value of an invocation to said callable.
# The invocation will receive the values of all other token attributes passed as keyword arguments.
assert Tastes.vanilla.display_name == "VANILLA!!"

# TokenAttribute dynamic value behavior is overridden/not used if value is set explicitly during Token instantiation.
assert Tastes.pecan_nut.display_name == "pecan nutz"

# A TokenContainer can be rendered as csv, excel, rst etc
assert """\
| display_name | opinion |
| VANILLA!! | |
| pecan nutz | Tasty |
""" == Tastes.to_rst(['display_name', 'opinion'])

Optional token attributes

.. code:: python

# A TokenAttribute may be declared as having optional dynamic values.
# That is, we want these dynamic attributes to be evaluated sometimes, but not always.
# In the example below, we want some superheroes to have homes, but not others.

SUPERHERO_HOMES = {'superman': 'Fortress of Solitude',
'batman': 'Batcave'}

class Superhero(Token):
name = TokenAttribute()
home = TokenAttribute(optional_value=lambda name, **_: SUPERHERO_HOMES[name])

# The PRESENT special value is used during Token instantiation to decide what
# optional token attributes should be evaluated.
class Superheroes(TokenContainer):
batman = Superhero(home=PRESENT)
hawkman = Superhero()
wonder_woman = Superhero(home='Themyscira')

# Batman has a home, but poor Hawkman does not.
assert Superheroes.batman.home == 'Batcave'
assert Superheroes.hawkman.home is None

# Just as with dynamic attributes, the logic for TokenAttribute optional dynamic values is overridden
if value is set explicitly during Token instantiation.
assert Superheroes.wonder_woman.home = 'Themyscira'

# As a shortcut, PRESENT for specific optional token attributes may be assigned to
# variables, and used in declarations, for enhanced readability.
# This is useful when one has tokens with many attributes declared using dynamic values,
# but we don't want all of them to be evaluated in all tokens.
home = PRESENT('home')

class Superheroes(TokenContainer):
batman = Superhero(home)
hawkman = Superhero()

# Again, Batman has a home, but poor Hawkman does not.
assert Superheroes.batman.home == 'Batcave'
assert Superheroes.hawkman.home is None

TokenAttribute inheritance

.. code:: python

class FooToken(Token):
foo = TokenAttribute(value=lambda **kwargs: 'foo_value')

class BarToken(Token):
bar = TokenAttribute()

class FieToken(FooToken, BarToken):
fie = TokenAttribute()

class FooBarFieTokenContainer(TokenContainer):
t = FieToken(fie=3)

assert dict(FooBarFieTokenContainer.t) == {'foo': 'foo_value', 'bar': None, 'name': 't', 'fie': 3}

TokenAttribute container inheritance

.. code:: python

class MyToken(Token):

name = TokenAttribute()
stuff = TokenAttribute()

class MyTokens(TokenContainer):

foo = MyToken(stuff='Hello')
bar = MyToken(stuff='World')

assert in MyTokens

class MoreTokens(MyTokens):
boink = MyToken(stuff='Other Stuff')

assert in MoreTokens

assert list(MoreTokens) == [,, MoreTokens.boink]
assert is

For more tri.token examples, please have a look at the contents of tests/ in the installation directory.

.. _test_tokens: tests/

Running tests

You need tox installed then just `make test`.





1.0.1 (2017-04-05)

* Changed metaclass handling to make PyCharm understand it

1.0.0 (2016-09-27)

* First released version on github

* Added documentation

* Cleanup of build machinery

0.6.0 (2016-04-11)

* Added documentation generation sort customisation

* Added python 3 support

0.5.0 (2016-02-01)

* Move dependency tri.cache.memoize from requirements.txt to test_requirements.txt. It is only used
for regression testing.

Project details

Release history Release notifications

This version
History Node


History Node


Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Filename, size & hash SHA256 hash help File type Python version Upload date
tri.token-1.0.1.tar.gz (9.1 kB) Copy SHA256 hash SHA256 Source None Apr 12, 2017

Supported by

Elastic Elastic Search Pingdom Pingdom Monitoring Google Google BigQuery Sentry Sentry Error logging CloudAMQP CloudAMQP RabbitMQ AWS AWS Cloud computing Fastly Fastly CDN DigiCert DigiCert EV certificate StatusPage StatusPage Status page