Special case for unary broadcasting, e.g. broadcast(-,::Zeros) (#106)

* Special case for unary broadcasting, e.g. broadcast(-,::Zeros)

* Update runtests.jl

Author: dlfivefifty

Project.toml

@@ -1,6 +1,6 @@
 name = "FillArrays"
 uuid = "1a297f60-69ca-5386-bcde-b61e274b549b"
-version = "0.8.12"
+version = "0.8.13"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"

src/fillbroadcast.jl

@@ -9,6 +9,10 @@ function broadcasted(::DefaultArrayStyle{N}, op, r::AbstractFill{T,N}) where {T,
     return Fill(op(getindex_value(r)), axes(r))
 end
 
+broadcasted(::DefaultArrayStyle, ::typeof(+), r::Zeros) = r
+broadcasted(::DefaultArrayStyle, ::typeof(-), r::Zeros) = r
+broadcasted(::DefaultArrayStyle, ::typeof(+), r::Ones) = r
+
 broadcasted(::DefaultArrayStyle{N}, ::typeof(conj), r::Zeros{T,N}) where {T,N} = r
 broadcasted(::DefaultArrayStyle{N}, ::typeof(conj), r::Ones{T,N}) where {T,N} = r
 broadcasted(::DefaultArrayStyle{N}, ::typeof(real), r::Zeros{T,N}) where {T,N} = Zeros{real(T)}(r.axes)

test/runtests.jl

@@ -477,7 +477,7 @@ end
     @test f.(x, Ones(5)) ≡ Fill(f(5,1.0),5)
 
     y = Ones(5,5)
-    @test (.+)(y) ≡ Fill(1.0,5,5)
+    @test (.+)(y) ≡ Ones(5,5)
     @test (.-)(y) ≡ Fill(-1.0,5,5)
     @test exp.(y) ≡ Fill(exp(1),5,5)
     @test y .+ 1 ≡ Fill(2.0,5,5)
@@ -542,7 +542,10 @@ end
     @test broadcast(*, rnge, Fill(5.0, 10)) == broadcast(*, rnge, 5.0)
     @test_throws DimensionMismatch broadcast(*, rnge, Fill(5.0, 11))
 
-    @testset "Special zeros" begin
+    @testset "Special Zeros/Ones" begin
+        @test broadcast(+,Zeros(5)) ≡ broadcast(-,Zeros(5)) ≡ Zeros(5)
+        @test broadcast(+,Ones(5)) ≡ Ones(5)
+
         @test Zeros(5) .* Ones(5) ≡ Zeros(5) .* 1 ≡ Zeros(5)
         @test Zeros(5) .* Fill(5.0, 5) ≡ Zeros(5) .* 5.0 ≡ Zeros(5)
         @test Ones(5) .* Zeros(5) ≡ 1 .* Zeros(5) ≡ Zeros(5)