Support appending arbitrary container

Project.toml

@@ -9,6 +9,7 @@ Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 Unicode = "4ec0a83e-493e-50e2-b9ac-8f72acf5a8f5"
 
 [compat]
+Tables = "1"
 julia = "1"
 
 [extras]

src/Table.jl

@@ -66,8 +66,7 @@ end
     end
 end
 
-Tables.istable(::Type{<:Table}) = true
-Tables.rowaccess(::Type{<:Table}) = true
+Tables.isrowtable(::Type{<:Table}) = true
 Tables.columnaccess(::Type{<:Table}) = true
 Tables.schema(::Table{T}) where {T} = Tables.Schema(T)
 Tables.materializer(::Table) = Table
@@ -199,6 +198,31 @@ function Base.append!(t::Table{<:NamedTuple{names}}, t2::Table{<:NamedTuple{name
     return t
 end
 
+_asnamedtuple(T) = data -> _asnamedtuple(T, data)
+function _asnamedtuple(::Type{T}, data) where {names, T<:NamedTuple{names}}
+    if data isa NamedTuple
+        return T(data)
+    else
+        return T(Tuple(getproperty(data, n) for n in names))
+    end
+end
+
+function append_columnaccess!(t::Table, t2)
+    cols = _asnamedtuple(NamedTuple{columnnames(t)}, columns(t2))
+    map(append!, columns(t), cols)
+    return t
+end
+
+append_rows!(t::Table, rows) =
+    mapfoldl(_asnamedtuple(NamedTuple{columnnames(t)}), push!, rows; init = t)
+
+function Base.append!(t::Table, rows)
+    if Tables.isrowtable(rows) && Tables.columnaccess(rows)
+        return append_columnaccess!(t, rows)
+    end
+    return append_rows!(t, rows)
+end
+
 function Base.popfirst!(t::Table)
     return map(popfirst!, columns(t))
 end

test/Table.jl

@@ -188,6 +188,26 @@
         @test isequal(Table(t |> rowtable), t)
     end
 
+    @testset "append!(_, rows(::$(typeof(t2))))" for t2 in Any[
+        [(a=3, b=4)],
+        (a=[3], b=[4]),
+    ]
+        t = Table(a=[1], b=[2])
+        @test append!(t, Tables.rows(t2)) == Table(a = [1, 3], b = [2, 4])
+    end
+
+    @testset "append! error handling" begin
+        err = nothing
+        @test try
+            append!(Table(a = [1], b = [2]), nothing)
+            false
+        catch err
+            true
+        end
+        @test err isa MethodError
+        @test err.f === iterate
+    end
+
     @testset "group" begin
         t = Table(a = [1,2,1], b = [2.0, 4.0, 6.0])
         out = group(getproperty(:a), t)