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Syntax for specifying Metaclasses in Hy

What is the syntax for for specifying metaclasses in Hy. I tried the following:

(defclass Metaclass [] )

(defclass Foo [ :meta Metaclass ] )
(defclass Foo [ [:meta Metaclass] ] )

but this did not work

Solution

  • You do it the same way you would in Python.

    This is on Python 3 and the latest master of Hy, and using the --spy option in the repl to show the Python compilation.

    => (defclass Foo [:metaclass print])
class Foo(metaclass=print):
    pass


None

Foo () {'__module__': '__console__', '__qualname__': 'Foo'}

    On Python 2.

    => (defclass Foo []
...  (setv __metaclass__ print))
class Foo:
    __metaclass__ = print


None

Foo () {'__module__': '__console__', '__metaclass__': <built-in function print>}

    If you need it to work for either, you could try installing the six compatibility library.