Erlang-like atoms in Python 3
Project description
Atum is a tiny Python library that you can use to emulate the basic functionality of Erlang’s atom in your Python scripts.
Status: Alpha; this is an experiment.
Erlang documentation:
http://erlang.org/doc/reference_manual/data_types.html
3.3 Atom
An atom is a literal, a constant with name. An atom is to be enclosed in single quotes (’) if it does not begin with a lower-case letter or if it contains other characters than alphanumeric characters, underscore (_), or @. Examples:
hello phone_number 'Monday' 'phone number'
Unlike Erlang’s atom, atum does not impose the same limitations. You may import any valid Python name from atum - even all uppercase.
Examples
Instead of writing:
@app.route('/register', methods=['GET', 'POST'])
def register():
pass
You could write:
from atum import GET, POST
@app.route('/register', methods=[GET, POST])
def register():
pass
This might be useful if you use autocompletion. Another benefit is exceptions occur sooner in case of typos, since the interpreter itself validates the imported names. Pay attention when importing, simply tab-to-complete later.
You can compare an atum with another atum or a string.
from atum import machine, human
assert human == human
assert machine == machine
assert machine == 'machine'
assert human != machine
assert human is human
assert machine is machine
Atums also make for readable sentinel values or event-names.
from atum import user_is_awake
from queue import Queue
q = Queue()
q.put(user_is_awake)
assert q.get() == user_is_awake
Technical Details
Atum simply imports Python strings with the same name as their content.
Here is the content of atum.py in its entirety:
import sys as _sys
class Atum(object):
def __getattr__(self, item):
if item.startswith('__'):
return self.__getattribute__(item)
return item
def __getitem__(self, item):
return item
_sys.modules[__name__] = Atum()
Known Issues
Atum does not support using @ in imported names as Python’s syntax does not allow it.
Project details
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