https://github.com/ahawker/decorstate
Simple "state machines" with Python decorators.
https://github.com/ahawker/decorstate
python python-decorators state-machine
Last synced: about 1 month ago
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Simple "state machines" with Python decorators.
- Host: GitHub
- URL: https://github.com/ahawker/decorstate
- Owner: ahawker
- License: apache-2.0
- Created: 2015-09-10T02:53:52.000Z (over 10 years ago)
- Default Branch: master
- Last Pushed: 2017-06-08T03:25:36.000Z (over 8 years ago)
- Last Synced: 2025-04-19T14:09:40.185Z (10 months ago)
- Topics: python, python-decorators, state-machine
- Language: Python
- Homepage:
- Size: 38.1 KB
- Stars: 12
- Watchers: 2
- Forks: 0
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# decorstate
[](https://travis-ci.org/ahawker/decorstate)
[](https://codeclimate.com/github/ahawker/decorstate/coverage)
[](https://codeclimate.com/github/ahawker/decorstate)
[](https://codeclimate.com/github/ahawker/decorstate)
[](https://badge.fury.io/py/decorstate)
[](https://pypi.python.org/pypi/decorstate)
[](https://pypi.python.org/pypi/decorstate)
Build dumb little "state machines" with Python decorators.
### Installation
To install decorstate from [pip](https://pypi.python.org/pypi/pip):
```bash
$ pip install decorstate
```
To install decorstate from source:
```bash
$ git clone git@github.com:ahawker/decorstate.git
$ cd decorstate
$ python setup.py install
```
### Usage
How do I use this pile?
```python
import decorstate
class Switch(object):
state = 'off'
@decorstate.transition('off', 'on')
def on(self, *args, **kwargs):
print 'You turned me on!'
@decorstate.transition('on', 'off')
def off(self, *args, **kwargs):
print 'You turned me off!'
>>> switch = Switch()
>>> switch.state
'off'
>>> switch.on()
You turned me on!
'on'
>>> switch.off()
You turned me off!
'off'
```
A switch? Really? How lame.
```python
import decorstate
class BrokenSwitch(object):
state = 'off'
@decorstate.transition('off', 'on')
def on(self, *args, **kwargs):
print 'You turned me on!'
@decorstate.transition('on', 'off')
def off(self, *args, **kwargs):
print 'You turned me off? Nah!'
@off.guard
def off(self, *args, **kwargs):
print 'Ha! I laugh at your feeble attempt!'
>>> broken_switch = BrokenSwitch()
>>> broken_switch.state
'off'
>>> broken_switch.on()
You turned me on!
'on'
>>> broken_switch.off()
Ha! I laugh at your feeble attempt!
'on'
>>> broken_switch.state
'on'
>>> broken_switch.off()
Ha! I laugh at your feeble attempt!
'on'
>>> broken_switch.state
'on'
```
A broken switch? Yawn.
```python
import decorstate
class InstantOffSwitch(object):
state = 'off'
@decorstate.transition('off', 'off')
def on(self, *args, **kwargs):
print 'You turned me on!'
@decorstate.transition('on', 'off')
def off(self, *args, **kwargs):
print 'You turned me off!'
@on.after
def on(self, *args, **kwargs):
print 'Ha! No light for you!'
>>> instant_off_switch = InstantOffSwitch()
>>> instant_off_switch.state
'off'
>>> instant_off_switch.on()
You turned me on!
Ha! No light for you!
'off'
>>> instant_off_switch.state
'off'
```
Well, that's kinda mean.
```python
import decorstate
import random
class IoTSwitch(object):
state = 'off'
@decorstate.transition('off', 'off')
def on(self, *args, **kwargs):
print 'You turned me on? Maybe...'
@decorstate.transition('on', 'off')
def off(self, *args, **kwargs):
print 'You turned me off? Maybe...'
@on.guard
def on(self, *args, **kwargs):
return self.coin_flip()
@off.guard
def off(self, *args, **kwargs):
return not self.coin_flip()
@staticmethod
def coin_flip():
return random.randint(1, 2) == 1
>>> iot_switch = IoTSwitch()
>>> iot_switch.state
'off'
>>> iot_switch.on()
'off'
>>> iot_switch.on()
'off'
>>> iot_switch.on()
'off'
>>> iot_switch.on()
You turned me on? Maybe...
'on'
>>> iot_switch.off()
'on'
>>> iot_switch.off()
'on'
>>> iot_switch.off()
'on'
>>> iot_switch.off()
'on'
>>> iot_switch.off()
You turned me off? Maybe...
'off'
```
Hey now, why you hating? Internet powered light switches are next level shit. My living room has its own twitter feed.
### Why?
I was interesting in doing something a bit more complex using the Python [descriptor protocol](https://docs.python.org/2/howto/descriptor.html).
### TODO?
Random thoughts and musing about potential changes/features.
* Consider adding the @machine decorator back as currently, you cannot use the "state", "transition" and "transition_event" attributes until the first transition has been performed since they are lazy created.
* Add event handler that fires only when "entering" a state and not when you perform multiple transitions but stay in the same state.
### License
[Apache 2.0](LICENSE)