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From: Terry Reedy <tjreedy@udel.edu>
Newsgroups: comp.lang.python
Subject: Re: Undefined behaviour in C [was Re: The Cost of Dynamism]
Date: Sun, 27 Mar 2016 12:39:30 -0400
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On 3/27/2016 11:48 AM, Ned Batchelder wrote:
> On Sunday, March 27, 2016 at 10:43:49 AM UTC-4, BartC wrote:

>> whether fn has an explicit return or not, and not allowing:
>>
>>     fn         # and other kinds of expression
>>
>> unless some keyword is used.
>
> Python *could* have made it an error to have a useless expression as a
> statement.

In interactive mode, which is an essential part of Python, expression 
statements print the value of the expression.  Thus no expression is 
useless.

So Bart is proposing to either disable an extremely useful feature or 
split Python into two slightly different dialects.  I think both are bad 
ideas.

-- 
Terry Jan Reedy