efficient idiomatic queue?

[Terry Reedy]

"Alex Martelli" <aleax at aleax.it> wrote in message
news:a23cjl$dps$1 at serv1.iunet.it...
> class DictFifo:
>     def __init__(self):
>         self.data = {}
>         self.nextin = 0
>         self.nextout = 0
>     def append(self, value):
>         self.data[self.nextin] = value
>         self.nextin += 1
>     def pop(self):
>         value = self.data[self.nextout]
>         del self.data[self.nextout]
>         self.nextout += 1

This clearly indicates the point of abstract data types separating
inplementation from interface.  In the real world, there are at least
two ways of implementing FIFO (first-in,first-out) service discipline.
One is to keep people in a physical line (sequence).  Another is to
'label' people in their order of entry -- for instance by giving them
or having them take a sequenced ticket --  and call them in order
while letting them physically mill around before getting called.
DictInfo above, while counter-intuitive to me at first, nicely mirrors
the second method, with sequential counts being the numbered
'tickets'.

Terry J. Reedy