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Permitting arbitrary annotations is a rather nice feature that, besides static analysis, opens the door for expressive runtime pre/postcondition checking functi

• jacobush 8y ago
  https://andreacensi.github.io/contracts/tour.html#quick-tour https://andreacensi.github.io/contracts/tour.html#quick-tour looks to be a stable solution for that.
• auscompgeek 8y ago
  Unfortunately PEP 563 [1] means that any non-type-hint usage of annotations is considered deprecated. You could still do things with decorators (like mentioned in a sibling comment), although I suppose that doesn't offer such an elegant syntax. [1]: https://www.python.org/dev/peps/pep-0563/#non-typing-usage-of-annotations https://www.python.org/dev/peps/pep-0563/#non-typing-usage-o...
• DonaldPShimoda 8y ago
  Although not really what they were intended for, somebody used annotations to provide a macro system [0]. [0] https://tinkering.xyz/abusing-type-annotations/ https://tinkering.xyz/abusing-type-annotations/
  • z_mitchell 8y ago
    Author here. Be warned, this was just a proof of concept that I did because I thought it would be fun/weird/interesting!
    • neoncontrails 8y ago
      Oh my goodness. I've committed some naughty deeds with the ast module before, but this is truly, wonderfully, heinous. You push this idea so far that I wouldn't even recognize some of these examples as syntactically valid, let alone predict their effects. I'm awestruck and a little frightened of you.