[Kirill Balunov <[email protected]>] > Not sure, but if additional motivating examples are required, there is a > common pattern for dynamic attribute lookup (snippet from `copy.py`): > > reductor = dispatch_table.get(cls) > if reductor: > rv = reductor(x) > else: > reductor = getattr(x, "__reduce_ex__", None) > if reductor: > rv = reductor(4) > else: > reductor = getattr(x, "__reduce__", None) > if reductor: > rv = reductor() > else: > raise Error("un(shallow)copyable object of type %s" % cls) > > which can with the current `binding expression` syntax simplified to: > > if reductor := dispatch_table.get(cls): > rv = reductor(x) > elif reductor := getattr(x, "__reduce_ex__", None): > rv = reductor(4) > elif reductor := getattr(x, "__reduce__", None): > rv = reductor() > else: > raise Error("un(shallow)copyable object of type %s" % cls) > > which becomes much clearer, at least in my opinion. > > With kind regards, > -gdg
Thanks for sharing that! While nobody else seems to, I absolutely love real code ;-) This is effectively an instance of Guido's "if/elif/elif/elif/..." example template, where binding expressions shine. But actual real code can make a point viscerally that "consider stuff akin to the following semi-abstract pattern" can't. _______________________________________________ Python-Dev mailing list [email protected] https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com