IteratorSize for infinite AbstractFill (#205)

* Forward IteratorSize to ProductIterator

* Add tests

* simplified implementation

* Add inference tests

* Any for Tuples

* Test on v1.9.0-beta3

* version bump to v0.13.7

.github/workflows/ci.yml

@@ -14,6 +14,7 @@ jobs:
         version:
           - '1.6'
           - '1'
+          - '~1.9.0-0'
         os:
           - ubuntu-latest
           - macOS-latest

Project.toml

@@ -1,6 +1,6 @@
 name = "FillArrays"
 uuid = "1a297f60-69ca-5386-bcde-b61e274b549b"
-version = "0.13.6"
+version = "0.13.7"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"

src/FillArrays.jl

@@ -61,6 +61,24 @@ IndexStyle(::Type{<:AbstractFill{<:Any,N,<:NTuple{N,Base.OneTo{Int}}}}) where N
 issymmetric(F::AbstractFill{<:Any, 2}) = axes(F,1) == axes(F,2)
 ishermitian(F::AbstractFill{<:Any, 2}) = issymmetric(F) && iszero(imag(getindex_value(F)))
 
+Base.IteratorSize(::Type{<:AbstractFill{T,N,Axes}}) where {T,N,Axes} = _IteratorSize(Axes)
+_IteratorSize(::Type{Tuple{}}) = Base.HasShape{0}()
+_IteratorSize(::Type{Tuple{T}}) where {T} = Base.IteratorSize(T)
+# Julia Base has an optimized any for Tuples on versions >= v1.9
+# On lower versions, a recursive implementation helps with type-inference
+if VERSION >= v"1.9.0-beta3"
+    _any(f, t::Tuple) = any(f, t)
+else
+    _any(f, ::Tuple{}) = false
+    _any(f, t::Tuple) = f(t[1]) || _any(f, Base.tail(t))
+end
+function _IteratorSize(::Type{T}) where {T<:Tuple}
+    N = fieldcount(T)
+    s = ntuple(i-> Base.IteratorSize(fieldtype(T, i)), N)
+    _any(x -> x isa Base.IsInfinite, s) ? Base.IsInfinite() : Base.HasShape{N}()
+end
+
+
 """
     Fill{T, N, Axes} where {T,N,Axes<:Tuple{Vararg{AbstractUnitRange,N}}}
 

test/infinitearrays.jl

@@ -35,6 +35,8 @@ module InfiniteArrays
     Base.last(r::AbstractInfUnitRange) = Infinity()
     Base.axes(r::AbstractInfUnitRange) = (OneToInf(),)
 
+    Base.IteratorSize(::Type{<:AbstractInfUnitRange}) = Base.IsInfinite()
+
     """
         OneToInf(n)
     Define an `AbstractInfUnitRange` that behaves like `1:∞`, with the added

test/runtests.jl

@@ -638,10 +638,20 @@ end
     @test_throws UndefKeywordError cumsum(Fill(1,1,5))
 
     @testset "infinite arrays" begin
-        A = Ones{Int}((InfiniteArrays.OneToInf(),))
+        r = InfiniteArrays.OneToInf()
+        A = Ones{Int}((r,))
         @test isinf(sum(A))
         @test sum(A) == length(A)
         @test sum(x->x^2, A) == sum(A.^2)
+        @testset "IteratorSize" begin
+            @test (@inferred Base.IteratorSize(Ones())) == Base.IteratorSize(ones())
+            @test (@inferred Base.IteratorSize(Ones(2))) == Base.IteratorSize(ones(2))
+            @test (@inferred Base.IteratorSize(Ones(r))) == Base.IsInfinite()
+            @test (@inferred Base.IteratorSize(Fill(2, (1:2, 1:2)))) == Base.HasShape{2}()
+            @test (@inferred Base.IteratorSize(Fill(2, (1:2, r)))) == Base.IsInfinite()
+            @test (@inferred Base.IteratorSize(Fill(2, (r, 1:2)))) == Base.IsInfinite()
+            @test (@inferred Base.IteratorSize(Fill(2, (r, r)))) == Base.IsInfinite()
+        end
     end
 end