[Python-ideas] Attribute-Getter Syntax Proposal

[Chris Angelico]

On Sat, Mar 9, 2019 at 9:09 AM Benedikt Werner
<1benediktwerner at gmail.com> wrote:
>
> This was actually quite interesting to code, thanks for the idea Jonathan!
>
> You can even support "magic.upper()" and "magic.real" at the same time
> as well as "magic[0]":
>
> class MagicClass:
>      NO_ARG = object()
>
>      @staticmethod
>      def __getattribute__(attr):
>          def method(x=MagicClass.NO_ARG):
>              if x is MagicClass.NO_ARG:
>                  return lambda x: getattr(x, attr)()
>              return getattr(x, attr)
>          return method
>
>      @staticmethod
>      def __getitem__(attr):
>          return lambda x: x[attr]
>
> magic = MagicClass()
>
> print(list(map(magic.upper(), ["abc", "def"])))  # ['ABC', 'DEF']
> print(list(map(magic.real, [1j, 2, 3+4j])))      # [0.0, 2, 3.0]
> print(list(map(magic[0], ["abc", "def"])))       # ['a', 'd']
>
> You could also use None instead of that NO_ARG thingy, because you most
> likely won't want to get any attributes of None objects, but that
> wouldn't produce proper errors incase you do anyways.
>
> With metaclasses you propably could also make it work directly on the
> class without the need of a magic instance.

Rather than using map in this way, I would recommend a list comprehension:

print([x.upper() for x in ["abc", "def"]])
print([x.real for x in [1j, 2, 3+4j]])
print([x[0] for x in ["abc", "def"]])

No magic needed.

ChrisA