range :by is one too high?

[AkashaP]

core/list/range

To me it makes sense if > (range :from 1 :to 10) out = (1 2 3 4 5 6 7 8 9 10)

was a shorthand for > (range :from 1 :to 10 :by 1)

but it is not, it is a shorthand for > (range :from 1 :to 10 :by 2) out = (1 2 3 4 5 6 7 8 9 10)

In fact, running > (range :from 1 :to 10 :by 1) causes an infinite loop which could be guarded against. Since it cant be negative may as well guard against :by (n < 1) too.

[SquidDev]

So this is technically working as expected, it's just very bad naming. range takes after Haskell's range operators. Where [1,3..9] is a shorthand for [1,3,5,7,9]. You can see this in the doc string:

> (range :from 1 :to 10)
out = (1 2 3 4 5 6 7 8 9 10)
> (range :from 1 :to 10 :by 3)
out = (1 3 5 7 9)

Really what you want is something like Python's range function (or just Lua/Urn's for loop), where it takes a step instead. Maybe we should also accept a :step parameter which provides this behaviour.

[listx]

Perhaps :then is a better name for :by. For example:

(range :from 1 :then 3 :to 9)

could translate to Haskell's [1,3..9].