Python Grammar (was Re: A TYPICAL NEWBIE MISTAKE?)

Andrew Dalke dalke at acm.org
Tue May 16 11:54:57 CEST 2000


Dirck:
>> Theoretically, a colon is only necessary in things like
>>
>> if yes: print "yes"


Moshe Zadka:
>Oddly enough, the parser doesn't really need the colon here either.
>It can manage to figure out where the if expression ends without it.
>
>The colon is almost entirely for readability purposes.
>(there are a couple of places where ambiguity occurs without it).


Oh, oh!  I've got one!

Is "if 1 - 1 - 2" the same as
   "if 1: -1 - 2" or
   "if 1-1: -2" or
   "if 1-1-2:"
?

Toss in some overflow exceptions past sys.maxint if you want to prove
that a good compiler won't optimize them away :)

Another is:

  if "spam" " eggs" " viking"

which, because of string joining during parsing, becomes:

  if "spam eggs viking"

instead of one of:
  if "spam": " eggs viking"
  if "spam eggs": " viking"

                    Andrew
                    dalke at acm.org






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