Change keys on VNT to return an array

Author: mhauru

src/varnamedtuple.jl

@@ -792,25 +792,18 @@ function apply!!(func, vnt::VarNamedTuple, name::VarName)
     return _setindex!!(vnt, new_subdata, name)
 end
 
-# TODO(mhauru) Should this return tuples, like it does now? That makes sense for
-# VarNamedTuple itself, but if there is a nested PartialArray the tuple might get very big.
-# Also, this is not very type stable, it fails even in basic cases. A generated function
-# would help, but I failed to make one. Might be something to do with a recursive
-# generated function.
 function Base.keys(vnt::VarNamedTuple)
-    result = ()
+    result = VarName[]
     for sym in keys(vnt.data)
         subdata = vnt.data[sym]
         if subdata isa VarNamedTuple
             subkeys = keys(subdata)
-            result = (
-                result..., (AbstractPPL.prefix(sk, VarName{sym}()) for sk in subkeys)...
-            )
+            append!(result, [AbstractPPL.prefix(sk, VarName{sym}()) for sk in subkeys])
         elseif subdata isa PartialArray
             subkeys = keys(subdata)
-            result = (result..., (VarName{sym}(lens) for lens in subkeys)...)
+            append!(result, [VarName{sym}(lens) for lens in subkeys])
         else
-            result = (result..., VarName{sym}())
+            push!(result, VarName{sym}())
         end
     end
     return result

test/varnamedtuple.jl

@@ -343,36 +343,36 @@ end
 
     @testset "keys" begin
         vnt = VarNamedTuple()
-        @test @inferred(keys(vnt)) == ()
+        @test @inferred(keys(vnt)) == VarName[]
 
         vnt = setindex!!(vnt, 1.0, @varname(a))
         # TODO(mhauru) that the below passes @inferred, but any of the later ones don't.
         # We should improve type stability of keys().
-        @test @inferred(keys(vnt)) == (@varname(a),)
+        @test @inferred(keys(vnt)) == [@varname(a)]
 
         vnt = setindex!!(vnt, [1, 2, 3], @varname(b))
-        @test keys(vnt) == (@varname(a), @varname(b))
+        @test keys(vnt) == [@varname(a), @varname(b)]
 
         vnt = setindex!!(vnt, 15, @varname(b[2]))
-        @test keys(vnt) == (@varname(a), @varname(b))
+        @test keys(vnt) == [@varname(a), @varname(b)]
 
         vnt = setindex!!(vnt, [10], @varname(c.x.y))
-        @test keys(vnt) == (@varname(a), @varname(b), @varname(c.x.y))
+        @test keys(vnt) == [@varname(a), @varname(b), @varname(c.x.y)]
 
         vnt = setindex!!(vnt, -1.0, @varname(d[4]))
-        @test keys(vnt) == (@varname(a), @varname(b), @varname(c.x.y), @varname(d[4]))
+        @test keys(vnt) == [@varname(a), @varname(b), @varname(c.x.y), @varname(d[4])]
 
         vnt = setindex!!(vnt, 2.0, @varname(e.f[3, 3].g.h[2, 4, 1].i))
-        @test keys(vnt) == (
+        @test keys(vnt) == [
             @varname(a),
             @varname(b),
             @varname(c.x.y),
             @varname(d[4]),
             @varname(e.f[3, 3].g.h[2, 4, 1].i),
-        )
+        ]
 
         vnt = setindex!!(vnt, fill(1.0, 4), @varname(j[1:4]))
-        @test keys(vnt) == (
+        @test keys(vnt) == [
             @varname(a),
             @varname(b),
             @varname(c.x.y),
@@ -382,10 +382,10 @@ end
             @varname(j[2]),
             @varname(j[3]),
             @varname(j[4]),
-        )
+        ]
 
         vnt = setindex!!(vnt, 1.0, @varname(j[6]))
-        @test keys(vnt) == (
+        @test keys(vnt) == [
             @varname(a),
             @varname(b),
             @varname(c.x.y),
@@ -396,10 +396,10 @@ end
             @varname(j[3]),
             @varname(j[4]),
             @varname(j[6]),
-        )
+        ]
 
         vnt = setindex!!(vnt, 1.0, @varname(n[2].a))
-        @test keys(vnt) == (
+        @test keys(vnt) == [
             @varname(a),
             @varname(b),
             @varname(c.x.y),
@@ -411,7 +411,7 @@ end
             @varname(j[4]),
             @varname(j[6]),
             @varname(n[2].a),
-        )
+        ]
     end
 
     @testset "printing" begin