Inconsistent return type of domain?

[singularitti]

I am trying two examples and using domain on them. But one returns a Tuple, the other returns a Vector. Could it be unified?

julia> p = Polynomial([1, 2, 3, 4])
Polynomial(1 + 2*x + 3*x^2 + 4*x^3)

julia> domain(p)
(-Inf, Inf)

julia> p = ChebyshevT([1, 0, 3, 4])
ChebyshevT(1⋅T_0(x) + 3⋅T_2(x) + 4⋅T_3(x))

julia> domain(p)
[-1, 1]

[jverzani]

Yes, that seems like a bug. No reason not to return a tuple in each.

[jverzani]

Oops, not a but. That is an artifact of show. The domain method returns an Interval.

[singularitti]

OK, I get it. Could it be Interval(-Inf, Inf) and Interval[-1, 1]?

[singularitti]

Another hint: Intervals.jl use a..b to represent intervals:

[jverzani]

Yeah, I didn't want to take on that dependency, but it is useful syntax. I wish .. were in base and not a package.

[singularitti]

Maybe we could take inspiration from both. How about this?

(-Inf..Inf)
[-1..1]

They are clearly neither vectors nor tuples.

[jverzani]

That is a show method. Would be nice, though better would be Polynomials.Interval[-1,1], as it isnt' an exported thing. Want to put in a PR? Let me know, o/w I can add it.

[singularitti]

I can make a PR. Which one do you like?

Polynomials.Interval[-1,1]

or [-1..1]?

[jverzani]

I like the latter with ( or ) for infinite values.

[singularitti]

It should work now: #460

julia> using Polynomials: domain

julia> p = Polynomial([1, 2, 3, 4])
Polynomial(1 + 2*x + 3*x^2 + 4*x^3)

julia> domain(p)
(-Inf..Inf)

julia> p = ChebyshevT([1, 0, 3, 4])
ChebyshevT(1⋅T_0(x) + 3⋅T_2(x) + 4⋅T_3(x))

julia> domain(p)
[-1..1]

[singularitti]

Closed by #460