Add method for collection of Features as StructArray-

Author: Sov-trotter

src/metadata.jl

@@ -8,36 +8,26 @@ Feature(x; kwargs...) = Feature(x, values(kwargs))
 Base.getproperty(f::Feature, s::Symbol) = s == :data ? getfield(f, 1) : s == :rest ? getfield(f, 2) : getproperty(getfield(f, 2), s)
 Base.propertynames(f::Feature) = (:data, propertynames(f.rest)...)
 
-#todo better function names
-"""
-Put a collection(Array) of Features in a StructArray
-"""
-function s_coll(iter::Array)
-    unnested_iter = Base.Generator(iter) do geom_meta
-        geom = getfield(geom_meta, :data) # well, the public accessor for this
-        metadata = getfield(geom_meta, :rest)
-        (; geometry=geom, metadata...) # I think the GeometryBasics name for this field is `:position`
-    end
-    soa = fieldarrays(StructArray(unnested_iter))
-    return Feature(soa.geometry; Base.tail(soa)...)
+getnamestypes(::Type{Feature{T, Names, Types}}) where {T, Names, Types} = (T, Names, Types) 
+
+function StructArrays.staticschema(::Type{F}) where {F<:Feature} #explicitly give the "schema" of the object to StructArrays
+    T, names, types = getnamestypes(F)
+    NamedTuple{(:data, names...), Base.tuple_type_cons(T, types)}
 end
 
-function GeometryBasics.Feature(elements::AbstractVector{XX}; rest...) where {XX}
-    isempty(rest) && return elements # no meta to add!
-    n = length(elements)
-    for (k, v) in rest
-        if v isa AbstractVector
-            mn = length(v)
-            mn != n && error("Metadata array needs to have same length as data.
-            Found $(n) data items, and $mn metadata items")
-        else
-            error("Metadata needs to be an array with the same length as data items. Found: $(typeof(v))")
-        end
-    end
-    nt = values(rest)
-    # get the first element to get the per element named tuple type
-    ElementNT = typeof(map(first, nt))
-    return StructArray((geometry = elements, nt...))
+function StructArrays.createinstance(::Type{F}, x, args...) where {F<:Feature} #generate an instance of Feature type 
+     T , names, types = getnamestypes(F)
+     Feature(x, NamedTuple{names, types}(args))
+end
+
+function structarray(iter)
+    cols = Tables.columntable(iter)
+    structarray(first(cols), Base.tail(cols)) 
+end
+
+function structarray(data, rest::NamedTuple{names, types}) where {names, types}
+    F = Feature{eltype(data), names, StructArrays.eltypes(types)}
+    return StructArray{F}(; data=data, rest...)
 end
 
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