This change does not carry changes in the logic, only syntactic
optimization.
Actually how it should work
Now the logic is written like this:
(Code 1)
for i in range (j):
...
else:
if i> 5:
...
The idea is to shorten it to a record like this:
(Code 2)
for i in range (j):
...
elif i> 5:
...
In fact, AST will remain unchanged.
Now AST for code 1 looks like this:
For (
...,
orelse = [
If (...)
]
)
It will look similar for code 2
Similar for the while loop:
Now the code looks like this:
while x:
...
else:
if y:
...
And it will be like this:
while x:
...
elif y:
...
As for the real cases where it will be applicable, I have already found
several in our project
For example, here in Tools/importbench/importbench.py
while total_time <seconds:
try:
total_time + = timer.timeit (1)
finally:
cleanup ()
count + = 1
else:
if total_time> seconds:
count - = 1
Or lib/idlelib/pyparse.py
while i <n:
ch = code [i]
i = i + 1
...
# some other huge calculations
...
else:
# didn't break out of the loop, so we're still
# inside a string
if (lno - 1) == firstlno:
# before the previous \ n in code, we were in the first
# line of the string
continuation = C_STRING_FIRST_LINE
else:
continuation = C_STRING_NEXT_LINES
вс, 15 дек. 2019 г. в 02:52, Ned Batchelder <n...@nedbatchelder.com>:
> On 12/14/19 4:37 PM, komissar.off.and...@gmail.com wrote:
> > Hello!
> > I think it will be useful in Python syntax if we can use "elif" in "for"
> and "while" statements besides "else"
> >
> > Example
> > for i in range(j):
> > ...
> > elif i > 5:
> > ...
> > else:
> > ...
> >
> > What you think about this change?
>
> Can you say what you want it to *mean*? What does it do?
>
> --Ned.
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