fix append!/prepend! for NodeChildren (#16)

Author: mortenpi

Project.toml

@@ -1,7 +1,7 @@
 name = "MarkdownAST"
 uuid = "d0879d2d-cac2-40c8-9cee-1863dc0c7391"
 authors = ["Morten Piibeleht <morten.piibeleht@gmail.com> and contributors"]
-version = "0.1.0"
+version = "0.1.1"
 
 [deps]
 AbstractTrees = "1520ce14-60c1-5f80-bbc7-55ef81b5835c"

src/node.jl

@@ -418,7 +418,7 @@ If any of `children` are part of another tree, then they are unlinked from that
     (see [JuliaLang/julia#15868](https://github.com/JuliaLang/julia/issues/15868)).
 """
 function Base.append!(nodechildren::NodeChildren{T}, children) where T
-    for child in children
+    for child in collect(children)
         isa(child, T) || throw(ArgumentError("invalid element type ($(typeof(child))) in children, expected $T"))
         push!(nodechildren, child)
     end
@@ -440,7 +440,7 @@ If any of `children` are part of another tree, then they are unlinked from that
     (see [JuliaLang/julia#15868](https://github.com/JuliaLang/julia/issues/15868)).
 """
 function Base.prepend!(nodechildren::NodeChildren{T}, children) where T
-    for child in Iterators.reverse(children)
+    for child in Iterators.reverse(collect(children))
         isa(child, T) || throw(ArgumentError("invalid element type ($(typeof(child))) in children, expected $T"))
         pushfirst!(nodechildren, child)
     end

test/node.jl

@@ -207,6 +207,19 @@ _startswith(prefix) = s -> startswith(s, prefix)
     # test, but with a generic iterator
     @test append!(n.children, c for c in cs) isa NodeChildren
     @test typeof.(getproperty.(n.children, :element)) == [DisplayMath, DisplayMath, Paragraph, CodeBlock, BlockQuote]
+    # test, but with elements from NodeChildren iterator
+    n2 = @ast Document() do
+        Heading(1)
+    end
+    @test append!(n2.children, n.children) isa NodeChildren
+    @test typeof.(getproperty.(n2.children, :element)) == [Heading, DisplayMath, DisplayMath, Paragraph, CodeBlock, BlockQuote]
+    @test isempty(n.children)
+    n3 = @ast Document() do
+        Heading(1)
+    end
+    @test prepend!(n3.children, n2.children) isa NodeChildren
+    @test typeof.(getproperty.(n3.children, :element)) == [Heading, DisplayMath, DisplayMath, Paragraph, CodeBlock, BlockQuote, Heading]
+    @test isempty(n2.children)
 
     # @ast macro with variables and function calls
     inner_tree = @ast Paragraph() do; "foo"; end