Add accessor for underlying vector of GroupPerm (#60)

* add accessor for GroupPerm

* add test

Author: piever

src/sort.jl

@@ -21,6 +21,7 @@ end
 GroupPerm(vec, perm=sortperm(vec)) = GroupPerm(vec, perm, axes(vec, 1))
 
 Base.sortperm(g::GroupPerm) = g.perm
+Base.parent(g::GroupPerm) = g.vec
 
 function Base.iterate(g::GroupPerm, i = first(g.within))
     vec, perm = g.vec, g.perm

test/runtests.jl

@@ -96,6 +96,7 @@ end
 @testset "iterators" begin
     c = [1, 2, 3, 1, 1]
     d = StructArrays.GroupPerm(c)
+    @test parent(d) == c
     @test eltype(d) == UnitRange{Int}
     @test Base.IteratorEltype(d) == Base.HasEltype()
     @test sortperm(d) == sortperm(c)