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do...until wisdom needed...
Ken PeekPeek at LVCM.comNOSPAM
Mon Apr 16 09:55:51 EDT 2001
OK--I will repeat a private email I sent to Paul Foley:I am writing my own language based on Python for deeply embedded systems. Iam not trying to change the Python language. I would like all of thetraditional looping constructs in my new language, and so was trying to getyour opinion as to the best way to implement a "do...until" construct. Yes,I know that the "while" construct CAN be used, but it is not the "syntacticcandy" that we have all come to know and love. I also plan on adding alogical XOR operator, a logical shift right, and a few other things such asabsolute static typing, constants, constant pointers (for directing absoluteI/O in memory mapped I/O systems), etc. etc.So, now that you know that I really am asking what I said I was asking, howabout answering my original question?--Thanks"Andrew Dalke" <dalke at acm.org> wrote in messagenews:9be82a$eq7$1 at slb6.atl.mindspring.net...> Ken Peek wrote:> >Thank you for the history lesson. My question still stands-- I> >don't care if it will be implemented or not. I am looking for> >what would be the correct "Pythonic" construct if it WERE implemented...>> >"Terry Reedy" <tjreedy at udel.edu> wrote:> >> This has been discussed ad nauseum for years with no agreement. If and> >> when maillist or newsgroup archives are available, you can review at your> >> leisure.>> But that's Terry's point. No one has decided on a "Pythonic"> construct, and there have been arguments on that topic. Nor> did he mention anything about implementation.>> I just did a www.python.org/search for "do while until". The> first hit was to:>http://groups.google.com/groups?q=do+while+until&hl=en&lr=&group=comp.lang.p> ython.*&safe=off&rnum=1&seld=943960637&ic=1> and since I don't know if that link will really work, the thread> is named "why no "do : until"? and took place last December.> (There are older threads, but not indexed by Google.)>> The consensus seems to be that there is no Pythonic syntax for> a do/until construct. It boils down to indentation. Both your> suggestions were proposed and it was decided that they didn't> make sufficient sense:>> do:> spam> until cond>> was found to be nothing more than an alias for>> while 1:> spam> if not cond: break>> and not worth introducing new syntax.>> The other proposal is:>> do:> spam> until cond>> but this "does not fit a pythonic pattern for statements"> (Martijn Faassen). Reread the full thread for details.>> So why didn't you believe that this exact history you were> looking for already existed in the easily searchable archives,> even after Terry pointed it out?>> Andrew>dalke at acm.org>>>>>>>
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