Reshape accepts a single colon for AbstractArrays (#220)

* reshape accepts one colon for AbstractArrays

* Add tests with different ndims

* fix offset for colon

Author: jishnub

src/utils.jl

@@ -11,7 +11,7 @@ _strip_IdOffsetRange(r::IdOffsetRange) = parent(r)
 _strip_IdOffsetRange(r) = r
 
 _offset(axparent::AbstractUnitRange, ax::AbstractUnitRange) = first(ax) - first(axparent)
-_offset(axparent::AbstractUnitRange, ax::Integer) = 1 - first(axparent)
+_offset(axparent::AbstractUnitRange, ::Union{Integer, Colon}) = 1 - first(axparent)
 
 """
     OffsetArrays.AxisConversionStyle(typeof(indices))

test/runtests.jl

@@ -1496,6 +1496,27 @@ end
     @test reshape(OffsetArray(-1:0, -1:0), :) == OffsetArray(-1:0, -1:0)
     @test reshape(A, :) == reshape(A0, :)
 
+    # reshape with one Colon for AbstractArrays
+    B = reshape(A0, -10:-9, :)
+    @test B isa OffsetArray{Int,2}
+    @test parent(B) === A0
+    @test axes(B, 1) == -10:-9
+    @test axes(B, 2) == axes(A0, 2)
+
+    B = reshape(A0, -10:-9, 3:3, :)
+    @test B isa OffsetArray{Int,3}
+    @test same_value(A0, B)
+    @test axes(B, 1) == -10:-9
+    @test axes(B, 2) == 3:3
+    @test axes(B, 3) == 1:2
+
+    B = reshape(A0, -10:-9, 3:4, :)
+    @test B isa OffsetArray{Int,3}
+    @test same_value(A0, B)
+    @test axes(B, 1) == -10:-9
+    @test axes(B, 2) == 3:4
+    @test axes(B, 3) == 1:1
+
     # pop the parent
     B = reshape(A, size(A))
     @test B == A0