convert to named tuple utility function (#53)

Author: piever

src/interface.jl

@@ -17,3 +17,14 @@ tuple_type(::Type{NamedTuple{names, types}}) where {names, types} = types
 function fields(::Type{T}) where {T}
     fieldnames(staticschema(T))
 end
+
+@generated function to_namedtuple(::Type{NT}, s::S) where {NT, S}
+    names = fieldnames(NT)
+    exprs = [Expr(:call, :getfieldindex, :s, QuoteNode(field), i) for (i, field) in enumerate(names)]
+    tup = Expr(:call, :tuple, exprs...)
+    :(NT($tup))
+end
+
+function to_namedtuple(s::S) where S
+    to_namedtuple(staticschema(S), s)
+end

test/runtests.jl

@@ -3,7 +3,6 @@ using StructArrays: LazyRow
 import Tables, PooledArrays, WeakRefStrings
 using Test
 
-# write your own tests here
 @testset "index" begin
     a, b = [1 2; 3 4], [4 5; 6 7]
     t = StructArray((a = a, b = b))
@@ -31,6 +30,13 @@ end
     @test isa(v_pooled.b, PooledArrays.PooledArray)
 end
 
+@testset "namedtuple" begin
+    @inferred StructArrays.to_namedtuple(1+2im)
+    @test StructArrays.to_namedtuple(1+2im) == (re = 1, im = 2)
+    @test StructArrays.to_namedtuple((a=1,)) == (a=1,)
+    @test StructArrays.to_namedtuple((1, 2, :s)) == (x1=1, x2=2, x3=:s)
+end
+
 @testset "permute" begin
     a = WeakRefStrings.StringVector(["a", "b", "c"])
     b = PooledArrays.PooledArray([1, 2, 3])