Feedback on Until recipe
MRAB
google at mrabarnett.plus.com
Thu Apr 26 18:30:20 EDT 2007
On Apr 26, 11:58 am, Antoon Pardon <apar... at forel.vub.ac.be> wrote:
> On 2007-04-24, Thomas Nelson <t... at mail.utexas.edu> wrote:
>
> > Occasionally someone posts to this group complaining about the lack of
> > "repeat ... until" in python. I too have occasionally wished for such
> > a construct, and after some thinking, I came up with the class below.
> > I'm hoping to get some feedback here, and if people besides me think
> > they might use it someday, I can put it on the python cookbook. I'm
> > pretty happy with it, the only ugly thing is you have to use a
> > lambda. Ideally i'd like to just see
> > while Until(i<3)
> > but that doesn't work.
> > Please tell me what you think, and thanks for your time.
>
> Maybe we should try to get the developers revive PEP 315.
>
> This PEP whould introduce a do-while statement that looks
> like the folowing:
>
> do
> statements
> while condition
> statements
>
> this would be equivallent to:
>
> while 1:
> statements
> if not condition:
> break
> statements
>
> Those wanting something like:
>
> repeat
> statements
> until condition
>
> Could then write something like:
>
> do
> statements
> while not condition
> pass
>
> Still not the most elegant but a vast improvement IMO.
>
At http://mail.python.org/pipermail/python-dev/2006-February/060718.html
Raymond Hettinger suggested removing the final colon after the 'while'
if there's no statement after it, which I agree with, although I would
prefer 'repeat' instead of 'do' (IMHO that doesn't suggest repetition
clearly enough):
repeat:
statements
while condition:
statements
and:
repeat:
statements
while condition
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