Generic support for known_length(::Type{<:AbstractCartesianIndex}) (#226)

Author: Tokazama

Project.toml

@@ -1,6 +1,6 @@
 name = "ArrayInterface"
 uuid = "4fba245c-0d91-5ea0-9b3e-6abc04ee57a9"
-version = "3.1.39"
+version = "3.1.40"
 
 [deps]
 Compat = "34da2185-b29b-5c13-b0c7-acf172513d20"

src/ArrayInterface.jl

@@ -92,7 +92,7 @@ known_length(::Type{T}) where {T<:Slice} = known_length(parent_type(T))
 known_length(::Type{<:Tuple{Vararg{Any,N}}}) where {N} = N
 known_length(::Type{T}) where {Itr,T<:Base.Generator{Itr}} = known_length(Itr)
 known_length(::Type{<:Number}) = 1
-known_length(::Type{NDIndex{N,I}}) where {N,I} = N
+known_length(::Type{<:AbstractCartesianIndex{N}}) where {N} = N
 function known_length(::Type{T}) where {T}
     if parent_type(T) <: T
         return nothing

test/runtests.jl

@@ -739,6 +739,7 @@ end
     @test ArrayInterface.known_length((1,)) == 1
     @test ArrayInterface.known_length((a=1,b=2)) == 2
     @test ArrayInterface.known_length([]) === nothing
+    @test ArrayInterface.known_length(CartesianIndex((1,2,3))) === 3
 
     x = view(SArray{Tuple{3,3,3}}(ones(3,3,3)), :, SOneTo(2), 2)
     @test @inferred(ArrayInterface.known_length(x)) == 6