PyWart: Language missing maximum constant of numeric types!

Rick Johnson rantingrickjohnson at gmail.com
Fri Feb 24 16:25:21 CET 2012


On Feb 24, 8:25 am, Neil Cerutti <ne... at norwich.edu> wrote:

> > What Python needs is some constant that can be compared to ANY
> > numeric type and that constant will ALWAYS be larger!
>
> What's the point of that?
>
> The only time I've naively pined for such a thing is when
> misapplying C idioms for finding a minimum value.

The best use case is for default arguments to constructors or func/
meths. If you set the argument to INFINITY instead of -1 (or some
other dumb string value to mean "unlimited") you can omit a useless
conditional block later. Observe:

if maxlength == -1 # unlimited length:
    keep_going()
elif len(object) < maxlength:
    stop() # because we reached the limit

I see tons and tons of old Python code that uses -1 as an "unlimited"
value, where positive numbers are meant to constrain dome value. I
have always found that to be intuitive; hence my question.



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