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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: In precision typing we trust
Date: Fri, 29 Aug 2025 10:15:56 +0200
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On 2025-08-29 05:54, Lawrence D’Oliveiro wrote:
> On Thu, 28 Aug 2025 11:43:15 +0200, Dmitry A. Kazakov wrote:
> 
>> In Python everything is untyped even when type annotations are used.
> 
>      Python 3.13.7 (main, Aug 20 2025, 22:17:40) [GCC 14.3.0] on linux
>      Type "help", "copyright", "credits" or "license" for more information.
>      >>> 2 + "2"
>      Traceback (most recent call last):
>        File "<python-input-0>", line 1, in <module>
>          2 + "2"
>          ~~^~~~~
>      TypeError: unsupported operand type(s) for +: 'int' and 'str'

"+" is implemented to raise an exception named TypeError. So? How is 
that a type check?

How do I know if that happens without executing "+"?

It is just untyped as no types of "+" are specified anywhere.

It is an undefined behavior, because nobody knows a-priory if "+" would 
return and which type or bomb the program.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de