Decorators - Python Wiki

A page for useful (or potentially abusive?) decorator ideas.

Category	Decorator	Summary
builtin	@property	Turn function into propery accessor, also: `@property.setter`
builtin	@classsmethod	Use `cls` instead of `self`
builtin	@staticmethod	Defines methods without self handle
stdlib	@functools.wraps	Retain modicum of meta infos (`__doc__`) of wrapped function
stdlib	@functools.singledispatch	Allows for divergent implementations per @f.register()
stdlib/backports	@functools.lru_cache	Wrap computationally expensive functions
stdlib	@functools.cmp_to_key	Transform an old-style comparison function to a key function.
stdlib	@functools.total_ordering	Adds any of the missing lt,le,eq,ge,gt comparison dunder methods
stdlib	@functools.partial	Prepopulate a couple of function arguments
stdlib	@contextlib.contextmanager	Uses generator protocol `yield` to turn function into `with`-able context mananger
stdlib	@dataclasses.dataclass	Adds various “dunder” methods to the class to streamline property access
stdlib	@atexit.register	Run as shutdown function
stdlib	@abc.ABCMeta.register	Turn into abstract base class
stdlib	@enum.unique	Guarantee unique members in enum class
stdlib	@xmlrpc.….register_function	...
asyncio	@coroutine	Outdated scheme for `async def`, deprecated in 3.8
asyncio	@throttle(2,1)	Reduce invocations per timeframe
asyncio	@exceptionCatcher…	Log exceptions more instantly
asyncio	@timeit	Basic benchmarking
async	@async_process	make func async and execute in other process
testing	@unittest.mock.patch	Override function w/ signature
testing	@wrapt.patch_function_wrapper	Override function w/ signature
decorator	@decorator	Assists declaring signature-preserving and single dispatch decorators
decorator	@decorator_args	Ease parameterizing decorators themselvess
decorator	@named_decorator	Retain callees' function name to simplify tracebacks
decorator	@dec.decorator(before=cb,after=cb)	Craft trivial enter/exit decorator
collect	@click.option("-d")	Argparse alternative
collect	@config_decorator.setting	Declarative dict structure for application settings
collect	@regex_decorator.listen	Register function callbacks for pattern matching
typing	@contract({"param":gt(3)})	Exhaustive function parameter constraints
flow handling	@__main__	Automatically run a function if invocation script
flow handling	@retry(times=2)	Reinvokes function a few times when encountering (temporary) exceptions, alt: pypi:retry-decorator
monkeypatching	@inject(modules…)	Shorthand assignment to modules/objects
monkeypatching	@monkeybiz.patch(fn)	Swap out function in object, retain reference to original

(Note: Not sure this is going anywhere. Relisting builtins is somewhat redundant, but topical. The focus is novel/interesting decorators in the wild. The categorization probably won't hold up.)

main

This decorator does not alter a function, but causes it to be executed if __name__ == '__main__'. This provides an experimental cleaner syntax to the traditional way of bootstrapping a python script. This should not be used on class methods.

The function gets a copied list of sys.argv arguments.

Toggle line numbers

   1 def __main__(func):
   2 
   3     if __name__ == "__main__":
   4         import sys, os
   5         args = sys.argv[:]
   6         args[0] = os.path.abspath(args[0])
   7         func(args)

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