[Kirill Balunov <kirillbalu...@gmail.com>]
> 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.
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