minor refactor and version bump (#198)

Author: Pietro Vertechi

Project.toml

@@ -1,6 +1,6 @@
 name = "StructArrays"
 uuid = "09ab397b-f2b6-538f-b94a-2f83cf4a842a"
-version = "0.6.0"
+version = "0.6.1"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"

src/structarray.jl

@@ -25,27 +25,24 @@ struct StructArray{T, N, C<:Tup, I} <: AbstractArray{T, N}
     end
 end
 
-# common type used for indexing
+# compute optimal type to use for indexing as a function of component types
 index_type(::Type{NamedTuple{names, types}}) where {names, types} = index_type(types)
 index_type(::Type{Tuple{}}) = Int
 function index_type(::Type{T}) where {T<:Tuple}
     S, U = tuple_type_head(T), tuple_type_tail(T)
-    IndexStyle(S) isa IndexCartesian ? CartesianIndex{ndims(S)} : index_type(U)
+    return _index_type(S, U)
 end
 # Julia v1.7.0-beta3 doesn't seem to specialize `index_type` as defined above
 # for tuple types with "many" elements (three or four, depending on the concrete
 # types). However, we can help the compiler for homogeneous types by defining
 # the specialization below.
-function index_type(::Type{<:NTuple{N, S}}) where {N, S}
-    if IndexStyle(S) isa IndexCartesian
-        return CartesianIndex{ndims(S)}
-    else
-        return Int
-    end
-end
-
+index_type(::Type{NTuple{N, S}}) where {N, S} = _index_type(S)
 index_type(::Type{StructArray{T, N, C, I}}) where {T, N, C, I} = I
 
+function _index_type(::Type{S}, ::Type{U}=Tuple{}) where {S, U}
+    return IndexStyle(S) isa IndexCartesian ? CartesianIndex{ndims(S)} : index_type(U)
+end
+
 array_types(::Type{StructArray{T, N, C, I}}) where {T, N, C, I} = array_types(C)
 array_types(::Type{NamedTuple{names, types}}) where {names, types} = types
 array_types(::Type{TT}) where {TT<:Tuple} = TT