Re: Does PIL (3rd edition) repeatedly misuse the length

[Tim Hill <drtimhill@...>]

On Sep 17, 2014, at 10:01 AM, Dirk Laurie <dirk.laurie@gmail.com> wrote:

> 2014-09-17 18:51 GMT+02:00 John Hind <john.hind@zen.co.uk>:
>> it is stretching the meaning of language to argue that "sets of the
>> form {1..0}" includes the empty set! Surely it is just an invalid
>> (meaningless) construction (or arguably the set {1})?
> 
> It is common practice in mathematics to interpret {1,2,3,...,n}
> as not implying that 1,2,3 are all actually elements of the set
> when n<3, and as denoting the empty set when n=0.
> 

Indeed, but I for one would vote for more clarity in the ref manual on this point, since it is, after all, a computer language text and not a math one.

—Tim