On 2019-12-21 4:58 p.m., Gregory Salvan wrote:
Years ago there was an interesting movement called anti-if campaign,
now it's more promotional, but the concept of "anti if" may help you
find ways to remove the cases where your suggest "and if" and "or if"
can apply.
This article is particularly well written:
https://code.joejag.com/2016/anti-if-the-missing-patterns.html
If you have cases where you think "and if" and "or if" can be helpful,
you probably underuse oop.
I would very much rather not be told that OOP is the be-all end-all of
programming. Python is not an OOP language. If you want to breathe and
preach OOP, you should quite frankly just use Java.
Le sam. 21 déc. 2019 à 20:32, Soni L. <fakedme...@gmail.com
<mailto:fakedme%2...@gmail.com>> a écrit :
On 2019-12-21 4:15 p.m., Andrew Barnert wrote:
> > On Dec 21, 2019, at 08:41, Soni L. <fakedme...@gmail.com
<mailto:fakedme%2...@gmail.com>> wrote:
> >
> > I'd like to see the ability to do:
> >
> > if x:
> > 1
> > and if y:
> > 2
> > or if z:
> > 3
> >
> > The truth table for these would be:
> >
> > x | y | z | result
> > 0 | _ | 0 | (none)
> > 0 | _ | 1 | 3
> > 1 | 0 | _ | 1,3
> > 1 | 1 | _ | 1,2,3
> >
> > and each statement is evaluated once, when encountered. (as
such, y and z may not be evaluated at all, if their evaluation is
not necessary to determine the outcome.)
>
> So this is equivalent to:
>
> if x:
> if y:
> 1, 2, 3
> else:
> 1, 3
> elif z:
> 3
>
> I can see how the former saves me having to repeat the 3 three
times. But the cost is being less obvious about when exactly I get
a 3 so I’m forced to work it through step by step—including the
confusion about the 1,0,0 case, which, as you mentioned, is only
clear if you imagine putting an else at the end (although maybe
you’d get used to that once you’d read through enough of these?).
It’s even less obvious if you do throw in an elif, or just add an
and if to the end (so now the condition to get there is not “x and
y or z and w” but, I think, “((x and y) or z) and w”?
>
> Does that advantage outweigh the disadvantage? Certainly not for
this example. But that’s probably because even the rewritten
example is meaningless and useless. Maybe it would be different
with a realistic use case, but I can’t imagine what that would be.
Surely you must have some case where you really wanted this, that
motivated you to propose it?
>
>
>
"1" and "2" and "3" are pieces of code, ofc.
it's actually more like:
if flag := x:
1
if y:
2
if flag or z: # note that "or" is short-circuiting.
3
but more efficiently implemented in bytecode without that "flag"
local
showing up.
it's literally meant for easing the translation of switch statements
from other languages and nothing else. (well, at least the "or if"
part.
the "and if" part isn't very useful. maybe to reduce deep
indentation I
guess?)
_______________________________________________
Python-ideas mailing list -- python-ideas@python.org
<mailto:python-ideas@python.org>
To unsubscribe send an email to python-ideas-le...@python.org
<mailto:python-ideas-le...@python.org>
https://mail.python.org/mailman3/lists/python-ideas.python.org/
Message archived at
https://mail.python.org/archives/list/python-ideas@python.org/message/NNVZQ5HITRW2357ED5SEWL5UDL4X5LWR/
Code of Conduct: http://python.org/psf/codeofconduct/
_______________________________________________
Python-ideas mailing list -- python-ideas@python.org
To unsubscribe send an email to python-ideas-le...@python.org
https://mail.python.org/mailman3/lists/python-ideas.python.org/
Message archived at
https://mail.python.org/archives/list/python-ideas@python.org/message/WNJUFZRW2ZJGE6CEVDTIESDBP47VD4N6/
Code of Conduct: http://python.org/psf/codeofconduct/
_______________________________________________
Python-ideas mailing list -- python-ideas@python.org
To unsubscribe send an email to python-ideas-le...@python.org
https://mail.python.org/mailman3/lists/python-ideas.python.org/
Message archived at
https://mail.python.org/archives/list/python-ideas@python.org/message/2B7Q2M52XF3TEH33ONLKFY2WZB4WG3XL/
Code of Conduct: http://python.org/psf/codeofconduct/
