add constructor from existing aos array (JuliaArrays#10)

Author: KristofferC

src/structarray.jl

@@ -31,6 +31,22 @@ StructArray{T}(args...) where {T} = StructArray{T}(NamedTuple{fields(T)}(args))
     end
 end
 
+@generated function StructArray(v::AbstractArray{T, N}) where {T, N}
+    syms = [gensym() for i in 1:fieldcount(T)]
+    init = Expr(:block, [:($(syms[i]) = similar(v, $(fieldtype(T, i)))) for i in 1:fieldcount(T)]...)
+    push = Expr(:block, [:($(syms[i])[j] = f.$(fieldname(T, i))) for i in 1:fieldcount(T)]...)
+    quote
+        $init
+        for (j, f) in enumerate(v)
+            @inbounds $push
+        end
+        return StructArray{T}($(syms...))
+    end
+end
+StructArray(s::StructArray) = copy(s)
+
+Base.convert(::Type{StructArray}, v::AbstractArray) = StructArray(v)
+
 columns(s::StructArray) = getfield(s, :columns)
 Base.getproperty(s::StructArray, key::Symbol) = getfield(columns(s), key)
 Base.getproperty(s::StructArray, key::Int) = getfield(columns(s), key)

test/runtests.jl

@@ -11,6 +11,17 @@ using Test
     @test (@inferred view(t, 2, 1:2)) == StructArray((a = view(a, 2, 1:2), b = view(b, 2, 1:2)))
 end
 
+@testset "constructor from existing array" begin
+    v = rand(ComplexF64, 5, 3)
+    t = @inferred StructArray(v)
+    @test size(t) == (5, 3)
+    @test t[2,2] == v[2,2]
+    t2 = convert(StructArray, v)::StructArray
+    @test t2 == t
+    t3 = StructArray(t)::StructArray
+    @test t3 == t
+end
+
 @testset "complex" begin
     a, b = [1 2; 3 4], [4 5; 6 7]
     t = StructArray{ComplexF64}(a, b)