Consolidate convert methods for BlockedUnitRange (#349)

Author: jishnub

src/blockaxis.jl

@@ -117,13 +117,20 @@ Return `all(blockisequal.(a,b))``
 blockisequal(a::Tuple, b::Tuple) = all(blockisequal.(a, b))
 
 
-Base.convert(::Type{BlockedUnitRange}, axis::BlockedUnitRange) = axis
-Base.convert(::Type{BlockedUnitRange}, axis::AbstractUnitRange{Int}) = _BlockedUnitRange(first(axis),[last(axis)])
-Base.convert(::Type{BlockedUnitRange}, axis::Base.Slice) = _BlockedUnitRange(first(axis),[last(axis)])
-Base.convert(::Type{BlockedUnitRange}, axis::Base.IdentityUnitRange) = _BlockedUnitRange(first(axis),[last(axis)])
-Base.convert(::Type{BlockedUnitRange{CS}}, axis::BlockedUnitRange{CS}) where CS = axis
-Base.convert(::Type{BlockedUnitRange{CS}}, axis::BlockedUnitRange) where CS = _BlockedUnitRange(first(axis), convert(CS, blocklasts(axis)))
-Base.convert(::Type{BlockedUnitRange{CS}}, axis::AbstractUnitRange{Int}) where CS = convert(BlockedUnitRange{CS}, convert(BlockedUnitRange, axis))
+_shift_blocklengths(::BlockedUnitRange, bl, f) = bl
+_shift_blocklengths(::Any, bl, f) = bl .+ (f - 1)
+const OneBasedRanges = Union{Base.OneTo, Base.Slice{<:Base.OneTo}, Base.IdentityUnitRange{<:Base.OneTo}}
+_shift_blocklengths(::OneBasedRanges, bl, f) = bl
+function Base.convert(::Type{BlockedUnitRange}, axis::AbstractUnitRange{Int})
+    bl = blocklasts(axis)
+    f = first(axis)
+    _BlockedUnitRange(f, _shift_blocklengths(axis, bl, f))
+end
+function Base.convert(::Type{BlockedUnitRange{CS}}, axis::AbstractUnitRange{Int}) where CS
+    bl = blocklasts(axis)
+    f = first(axis)
+    _BlockedUnitRange(f, convert(CS, _shift_blocklengths(axis, bl, f)))
+end
 
 Base.unitrange(b::BlockedUnitRange) = first(b):last(b)
 

test/test_blockindices.jl

@@ -215,12 +215,23 @@ end
         b = blockedrange(Fill(2,3))
         c = blockedrange([2,2,2])
         @test convert(BlockedUnitRange, b) === b
-        @test blockisequal(convert(BlockedUnitRange, Base.OneTo(5)), blockedrange([5]))
-        @test blockisequal(convert(BlockedUnitRange, Base.Slice(Base.OneTo(5))), blockedrange([5]))
-        @test blockisequal(convert(BlockedUnitRange, Base.IdentityUnitRange(-2:2)), BlockArrays._BlockedUnitRange(-2,[2]))
-        @test convert(BlockedUnitRange{Vector{Int}}, c) === c
-        @test blockisequal(convert(BlockedUnitRange{Vector{Int}}, b),b)
-        @test blockisequal(convert(BlockedUnitRange{Vector{Int}}, Base.OneTo(5)), blockedrange([5]))
+        @test convert(typeof(b), b) === b
+        @test convert(BlockedUnitRange, c) === c
+        @test convert(typeof(c), c) === c
+        function test_type_and_blocks(T, r, res)
+            s = convert(T, r)
+            @test s isa T
+            @test blockisequal(s, res)
+        end
+        for T in (BlockedUnitRange, BlockedUnitRange{Vector{Int}})
+            test_type_and_blocks(T, blockedrange(5:5), blockedrange(5:5))
+            test_type_and_blocks(T, Base.OneTo(5), blockedrange([5]))
+            test_type_and_blocks(T, Base.Slice(Base.OneTo(5)), blockedrange([5]))
+            test_type_and_blocks(T, -2:2, BlockArrays._BlockedUnitRange(-2,[2]))
+            test_type_and_blocks(T, Base.IdentityUnitRange(-2:2), BlockArrays._BlockedUnitRange(-2,[2]))
+            test_type_and_blocks(T, b, b)
+            test_type_and_blocks(T, Base.OneTo(5), blockedrange([5]))
+        end
     end
 
     @testset "findblock" begin