Re: ABCs -> infix syntax for isinstance() ?

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  • Terry Reedy

    Re: ABCs -> infix syntax for isinstance() ?

    Boris Borcic wrote:
    Given the ABC innovation, maybe an infix syntax for isinstance() would
    be good.
    >
    Possibilities :
    >
    - stealing "is" away from object identity. As a motivation, true use
    cases for testing object identity are rare; forcing the usage of a
    function or method to test it, would dissuade abuse.
    >
    - allowing containment tests, ie "x in Number" to invoke isinstance() in
    the background when the container is of type <type>. My brain is too
    muddled by flu at the moment, to see whether Guido's fabled time machine
    allowed him to already provide all the necessities in py26.
    Any takers ?
    I believe this could be done by adding a __contains__ method to type.
    (It does not have one now). Then x in X should work for all classes
    that are instances of type or a subclass thereof.

    - combining both keywords to create a third one, eg "is in"
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