[Python-Dev] Issue #26204: compiler now emits a SyntaxWarning on constant statement

[Michel Desmoulin]

Hello,

Le 08/02/2016 20:13, Guido van Rossum a écrit :
> On Mon, Feb 8, 2016 at 9:44 AM, Victor Stinner <victor.stinner at gmail.com> wrote:
>> I changed the Python compiler to ignore any kind "constant
>> expressions", whereas it only ignored strings and integers before:
>> http://bugs.python.org/issue26204
>>
>> The compiler now also emits a SyntaxWarning on such case. IMHO the
>> warning can help to detect bugs for developers who just learnt Python.
> Hum. I'm not excited by this idea. It is not bad syntax. Have you
> actually seen newbies who were confused by such things?
>


I give regular Python trainings and I see similar errors regularly such as:

- not returning something;
- using something without putting the result back in a variable.

However, these are impossible to warn about.

What's more, I have yet to see somebody creating a constant and not 
doing anything with it. I never worked with Ruby dev though.

My sample of dev is not big enough to be significant, but I haven't met 
this issue yet. I still like the idea, anything making Python easier for 
beginers is a good thing for me.

One particular argument against it is the use of linters, but you must 
realize most beginers don't use linters. Just like they don't use 
virtualenv, pip, pdb, etc. They are part of a toolkit you learn to use 
on the way, but not something you start with. Besides, many people using 
Python are not dev, and will just never take the time to use linters, 
not learn about them.