Implement iteration protocol

.github/workflows/CI.yml

@@ -21,7 +21,7 @@ jobs:
       fail-fast: false
       matrix:
         version:
-          - '1.0'
+          - '1.6'
           - '1'
           - 'nightly'
         os:

Project.toml

@@ -4,7 +4,7 @@ authors = ["Mosè Giordano"]
 version = "0.1.0"
 
 [compat]
-julia = "1"
+julia = "1.6"
 
 [extras]
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

src/StarWarsArrays.jl

@@ -78,12 +78,36 @@ Base.setindex!(A::StarWarsArray, v, i::Int) =
 Base.setindex!(A::StarWarsArray{T,N}, v, i::Vararg{Int,N}) where {T,N} =
     setindex!(parent(A), v, index.(i, size(parent(A)), order(A))...)
 
+# Axes
 Base.axes(A::StarWarsArray{T,N,P,OriginalOrder}) where {T,N,P} =
     map(i->index.(i, length(A), order(A)), machete_view_index.(size(A)))
 
 Base.axes(A::StarWarsArray{T,N,P,MacheteOrder}) where {T,N,P} =
     map(i->index.(i .+ 1, length(A), MacheteOrder), machete_view_index.(size(A)))
 
+# Iteration
+function iterate_revindex(i::Int, ::Type{OriginalOrder})
+    if 1 <= i <= 3
+        return i + 3
+    elseif 4 <= i <= 6
+        return i - 3
+    end
+    return i
+end
+function iterate_revindex(i::Int, ::Type{MacheteOrder})
+    if 1 <= i <= 2
+        return i + 3
+    elseif 3 <= i <= 4
+        return i - 1
+    end
+    return i + 1
+end
+
+function Base.iterate(A::StarWarsArray, i=1)
+    i in 1:length(A) || return nothing
+    return A[iterate_revindex(i, order(A))], i + 1
+end
+
 # Showing.  Note: this is awful, but it does what I want
 Base.show(io::IO, m::MIME"text/plain", A::StarWarsArray{T,N}) where {T,N} =
     show(io, m, view(parent(A), axes(A)...))

test/runtests.jl

@@ -16,8 +16,14 @@ import StarWarsArrays: StarWarsError, order
     v[4] = -42
     @test v[4] == -42
     @test axes(v) == ([4, 5, 6, 1, 2, 3, 7, 8, 9],)
+    @test eachindex(v) == [4, 5, 6, 1, 2, 3, 7, 8, 9]
     @test length(v) == 9
     @test size(v) == (9,)
+    for (idx, x) in enumerate(v)
+        # Explanation: iterating over `v` should be equivalent to iterating over its parent,
+        # because the iteration protocol should follow the order 4, 5, 6, 1, 2, 3, ...
+        @test x == parent(v)[idx]
+    end
 
     m = StarWarsArray(reshape(collect(1:81), 9, 9), OriginalOrder)
     @test order(m) == OriginalOrder
@@ -36,6 +42,9 @@ import StarWarsArrays: StarWarsError, order
     @test axes(m) == ([4, 5, 6, 1, 2, 3, 7, 8, 9], [4, 5, 6, 1, 2, 3, 7, 8, 9])
     @test length(m) == 81
     @test size(m) == (9, 9)
+    for (idx, x) in enumerate(m)
+        @test x == parent(m)[idx]
+    end
 
     @test_throws ArgumentError StarWarsArray(rand(2), OriginalOrder)
     @test_throws ArgumentError StarWarsArray(rand(8, 2), OriginalOrder)
@@ -56,8 +65,12 @@ end
     v[4] = -42
     @test v[4] == -42
     @test axes(v) == ([3, 4, 1, 2, 5, 6, 7, 8],)
+    @test eachindex(v) == [3, 4, 1, 2, 5, 6, 7, 8]
     @test length(v) == 8
     @test size(v) == (8,)
+    for (idx, x) in enumerate(v)
+        @test x == parent(v)[idx]
+    end
 
     m = StarWarsArray(reshape(collect(1:81), 9, 9), MacheteOrder)
     @test order(m) == MacheteOrder
@@ -81,6 +94,9 @@ end
     @test axes(m) == ([3, 4, 1, 2, 5, 6, 7, 8], [3, 4, 1, 2, 5, 6, 7, 8])
     @test length(m) == 64
     @test size(m) == (8, 8)
+    for (idx, x) in enumerate(m)
+        @test x == parent(m)[idx]
+    end
 
     @test_throws ArgumentError StarWarsArray(rand(4), MacheteOrder)
     @test_throws ArgumentError StarWarsArray(rand(6, 2, 9), MacheteOrder)