optenum 1.1.0

A missing Python Option/Enum library

Optenum

A missing Python Option/Enum library which supports enum code, name, text, even (code, name) tuple list and so on.

Name "optenum" comes from 'option' + 'enumeration'.

Compatible with Python 2.7+ and Python 3.0+.

Install

Python 3.x, 2.7

pip install optenum

For those probably missing six module:

pip install six optenum

Quick start

1. Simple as Enum type

   Says we define a simple enum:

   from optenum import Options
   
   class Fruit(Options):
       APPLE = 1
       ORANGE = 2
       BANANA = 3 
   

   Try the following in Python command line:

   >>> from optenum import Option, Options
   >>> class Fruit(Options):
   ...     APPLE = 1
   ...     ORANGE = 2
   ...     BANANA = 3
   >>> 
   >>> Fruit.APPLE
   <Option code=1 name=APPLE text=None>
   >>> print(Fruit.APPLE)
   1
   >>> Fruit.APPLE.code
   1
   >>> Fruit.APPLE.name
   'APPLE'
   >>> Fruit.APPLE.text
   >>> print(Fruit.APPLE.text)
   None
   >>> Fruit.APPLE.get_text()
   'apple'
   
   

2. Complex declaration

   You may declare your Options (Enums) in many annotations.

   from optenum import Option, Options
   
   class EnumCellPhone(Options):
       APPLE = 1
       SAMSUNG = Option(2, name='SAMSUNG')
       HUAWEI = 3, 'Huawei cellphone'     # tuple annotation. name = code, text
   
   
   class DoorState(Options):
       OPEN = 'O', 'Door is opened'       # tuple annotation. name = code, text
       CLOSED = ('C', 'Door is closed')   # tuple annotation, too.
       IN_OPENING = 'IO'
       IN_CLOSING = 'IC'
   
       _FLAG = False           # underscore leading name is not an option
       x = lambda y: y         # function/callable is not an option
   

3. Operators

   Option support some operators. See more in operators.md.

   >>> class Favorite(Options):
   ...     APPLE = 1
   ...     BANANA = 3, 'Banana hot'
   ... 
   >>> 
   >>> Fruit.APPLE == Favorite.APPLE
   True
   >>> Fruit.BANANA == Favorite.BANANA
   False
   >>> Fruit.APPLE + 1 == Fruit.ORANGE
   True>>> Fruit.BANANA >> 2
   0
   >>> Fruit.BANANA << 2
   12>>> Fruit.BANANA > Favorite.APPLE
   True
   

4. Collections

   Options provides some collections for accessing option and it's fields. See section "Collections for Options" below for more information.

   >>> Fruit.codes
   [1, 2, 3]
   >>> Fruit.names
   ['ORANGE', 'APPLE', 'BANANA']
   >>> Fruit.all
   [<Option code=2 name=ORANGE text=None>, <Option code=1 name=APPLE text=None>, <Option code=3 name=BANANA text=None>]
   >>> Fruit.tuples
   [('ORANGE', 2, None), ('APPLE', 1, None), ('BANANA', 3, None)]
   >>> Favorite.items
   {'APPLE': <Option code=1 name=APPLE text=None>, 'BANANA': <Option code=3 name=BANANA text=Banana hot>}
   >>> Favorite.get_list('code','text')
   [(1, None), (3, 'Banana hot')]
   >>> Favorite.get_dict('name','text')
   {'APPLE': None, 'BANANA': 'Banana hot'}
   
   

5. Django model choices

    To be written
   

Background

Often we need to define some enums or options. But looks python missing this class. Sometimes we uses class, tuples or dict as the replacement. But they are not convenience.

For example, we could define a class as enumeration. We can use MyOption.foo to get the enum value 1.

class MyOption(object):
    foo = 1
    bar = 2

But how can we get the enum name foo ? How can we get the list of all enums ? Even list of tuples [ (1, 'foo'), (2, 'bar')] (useful in Django model)

Although Python 3.7 comes with data classes. So far it looks like a piece of syntax sugar for me and it can not solve these problems.

Features

• Code - Enumeration/options by different types - e.g. 0, 1, -1 (or 'new', 'running', 'stopped')
• Name - Name of an enum/option - e.g. 'NEW', 'RUNNING', 'STOPPED'. Support dot access.
• Text - Meaning or description of the enum/option. support i18n - e.g. _('new'), _('running'), _('stopped') (translated to '新建', '运行中', ‘停止中’)
• List - Retrieve list of code, name or text [0, 1, -1]
• Dict - Retrieve dict of {code: name} mapping. even {code: text}, {name: text} mapping if required.
• List of tuples - Retrieve list of [(code, name), ...] tuples. Useful in Django model.
• Operators support - e.g. Fruit.APPLE == 1, Fruit.BANANA > Fruit.APPLE
• Grouping - Group a set of enums/options. e.g. IN_PROGRESS_STATE = ['STARTING', 'STOPPING'], but 'STARTED' and 'STOPPED' are not belongs to it.
• Access name, text by code
• Lookup enum/option by name, code

Guide / Tutor

Type converting for Option

str() or implicit string converting will convert Option.code to string type and returns.

repr() will returns the object as string format of <Option code=??? name=??? text=???>.

int, float will be performed on Option.code and returns the value or raises corresponding exception.

Boolean for Option

No special implementation. It behaves as object is.

Operators for Option

Option.code is the real value of the enum/option item. Somehow we need to use codes like if active_state == MyOption.RUNNING.code: # Do something ... to check the status. For convenience using it, some of the operators are override. Then we could use if active_state == MyOption.RUNNING:, x = MyOption.RUNNING + 1 and so on to directly reference to its real value.

See doc operators.md for override operators.

Collections for Options

Option can be accessed directly as subscribe annotation. For example Option['FOO'] equals to Option.FOO.

We could also access the following collections from within an Options class.

• Options.codes - list of codes

• Options.names - list of names

• Options.all - list of options

• Options.tuples - list of (name, code, text) tuple

• Options.items - dict of {name: Option} mapping

• Options.get_list(*fields) - list of *files tuple. *fields are names of Option filed such as code, *(name, code) or *(code, name, text)

• Options.get_dict(key_field, *fields) - dict of {key_filed: (*fields)} ({str: tuple}) mapping. key_field specify which Option field is key such as name, code. fields specify the value tuple combined of which Option fields such as (name, text) or name. if fields is tuple, the value is tuple. if fields is single filed, value is single field.

in operator could check if a code in Options. e.g. if Fruit.APPLE in Fruit. The Option.name will not work. e.g. if 'APPLE' in Fruit will got False. If you want to check if name in Options), use collection instead. e.g. if 'APPLE' in Fruit.names.

Configuration

Some flags can be used to make some simple configuration to your Options.

• __IGNORE_INVALID_NAME__ - Ignore invalid Option name so that you may add your own attribute/function to class.

  Underscore _ leading attributes and any functions will be ignored so that you can add your own attributes and functions. The following example is valid definition.

  from optenum import Options
  
  class MyEnum(Options):
      FOO = 1
      BAR = 2
  
      _flag = False
  
      def switch(self):
          pass
  

  But if an attributes is not uppercase (all characters), it will be treat as invalid Option and cause exception.

  from optenum import Options
  
  class MyEnum(Options):
      FOO = 1
      BAR = 2
  
      Baz = 3     # <- Invalid Option name. Exception raised.
  

  If you want this available, add __IGNORE_INVALID_NAME__ to your class like below. The exception will ignored. But to be noticed, it still not an Option.

  from optenum import Options
  
  class MyEnum(Options):
      __IGNORE_INVALID_NAME__ = True
  
      FOO = 1
      BAR = 2
  
      Baz = 3     # <- Exception ignored. But still not an Option.
  

• __ORDER_BY__

  Not supported yet
  

FAQ

• Why not use namedtuple ?

namedtuple is also a good way to define enum/options. But it has not enough features you may required such as collection, operator, compare, text and so on.

• To be added

Contributors

List of contributors:

• Samuel Chen - The project owner and maintainer.