Add Base.copy(::Node)

README.md

@@ -99,18 +99,49 @@ node["key"] = value
 node["key"]
 ```
 
-- `Node` is an immutable type.  However, you can easily create a copy with one or more field values changed by using the `Node(::Node; kw...)` constructor where `kw` are the fields you want to change.  For example:
+- `Node` is an immutable type.  However, you can easily create a simple copy using `copy(::Node)` or 
+copy with one or more changes by using the `Node(::Node, atts...; kw...)` constructor where `atts` 
+are new children to add and `kw` are the node attributes you want to add or change.  For example:
 
 ```julia
-node = XML.Element("tag", XML.Text("child"))
+julia> node = XML.Element("tag", XML.Text("child"))
+Node Element <tag> (1 child)
 
-simple_value(node)
-# "child"
+julia> simple_value(node)
+"child"
 
-node2 = Node(node, children=XML.Text("changed"))
+julia> node2 = Node(node, new_att="I'm new")
+Node Element <tag new_att="I'm new"> (1 child)
 
-simple_value(node2)
-# "changed"
+julia> node3 = Node(node2, XML.Element("new_child", child_att="I'm new too"))
+Node Element <tag new_att="I'm new"> (2 children)
+
+julia> println(XML.write(node))
+<tag>child</tag>
+
+julia> println(XML.write(node2))
+<tag new_att="I'm new">child</tag>
+
+julia> println(XML.write(node3))
+<tag new_att="I'm new">
+  child
+  <new_child child_att="I'm new too"/>
+</tag>
+
+julia> node4=copy(node3)
+Node Element <tag new_att="I'm new"> (2 children)
+
+julia> println(XML.write(node4))
+<tag new_att="I'm new">
+  child
+  <new_child child_att="I'm new too"/>
+</tag>
+
+julia> node4==node3
+true
+
+julia> node4===node3
+false
 ```
 
 ### Writing `Element` `Node`s with `XML.h`

src/XML.jl

@@ -171,7 +171,8 @@ Node(data::Raw) = Node(LazyNode(data))
 # Anything that's not Vector{UInt8} or a (Lazy)Node is converted to a Text Node
 Node(x) = Node(Text, nothing, nothing, string(x), nothing)
 
-h(tag::Union{Symbol, String}, children...; kw...) = Node(Element, tag, kw, nothing, children)
+h(tag::Union{Symbol, String}, children...; kw...) = Node(Element, tag, length(kw)==0 ? nothing : kw, nothing, children)
+# h(tag::Union{Symbol, String}, children...; kw...) = Node(Element, tag, kw, nothing, children)
 Base.getproperty(::typeof(h), tag::Symbol) = h(tag)
 (o::Node)(children...; kw...) = Node(o, Node.(children)...; kw...)
 
@@ -204,7 +205,12 @@ Base.setindex!(o::Node, val, i::Integer) = o.children[i] = Node(val)
 Base.push!(a::Node, b::Node) = push!(a.children, b)
 Base.pushfirst!(a::Node, b::Node) = pushfirst!(a.children, b)
 
-Base.setindex!(o::Node, val, key::AbstractString) = (o.attributes[key] = string(val))
+function Base.setindex!(o::Node, val, key::AbstractString) # Need to deal with case that XML.attributes(o) === nothing
+    o = isnothing(o.attributes) ? XML.Node(o.nodetype, o.tag, OrderedDict{String, String}(), o.value, o.children) : o
+    o.attributes[key] = string(val)
+    return o
+end
+# Base.setindex!(o::Node, val, key::AbstractString) = (o.attributes[key] = string(val))
 Base.getindex(o::Node, val::AbstractString) = o.attributes[val]
 Base.haskey(o::Node, key::AbstractString) = isnothing(o.attributes) ? false : haskey(o.attributes, key)
 Base.keys(o::Node) = isnothing(o.attributes) ? () : keys(o.attributes)
@@ -240,7 +246,8 @@ function (T::NodeType)(args...; attr...)
         Node(T, nothing, nothing, only(args))
     elseif T === Element
         tag = first(args)
-        Node(T, tag, attr, nothing, args[2:end])
+        Node(T, tag, length(attr)==0 ? nothing : attr, nothing, args[2:end])
+#        Node(T, tag, attr, nothing, args[2:end])
     else
         error("Unreachable reached while trying to create a Node via (::NodeType)(args...; kw...).")
     end
@@ -269,6 +276,10 @@ simple_value(o) = is_simple(o) ? value(only(o)) : error("`XML.simple_value` is o
 
 Base.@deprecate_binding simplevalue simple_value
 
+#-----------------------------------------------------------------------------# copy node
+
+Base.copy(o::AbstractXMLNode) = Node(o.nodetype, o.tag, o.attributes, o.value, isnothing(o.children) ? nothing : [Base.copy(x) for x in o.children])
+
 #-----------------------------------------------------------------------------# nodes_equal
 function nodes_equal(a, b)
     out = XML.tag(a) == XML.tag(b)

test/runtests.jl

@@ -174,6 +174,16 @@ end
     end
 end
 
+#-----------------------------------------------------------------------------# copy
+@testset "Copy node" begin
+    for path in all_files
+        node = read(path, Node)
+        node2 = copy(node)
+        @test node == node2
+        @test node2==deepcopy(node)
+    end
+end
+
 #-----------------------------------------------------------------------------# roundtrip
 @testset "read/write/read roundtrip" begin
     for path in all_files