Fun with DSLs, Coco style.

gistfile1.coffee

X = (tag, content=null, attrs={}, parent=null) ->
  if content and typeof content != "string" => attrs = content; content = null
	node = ({tag, content, attrs}) => parent?@@children.push &
	((tag, content=null, attrs={}) -> X tag, content, attrs, node) => &node=node

render = (node, emit=console.log, indent=0) ->
	node = node?.node || node
	empty = true unless node.content or node.children
	idt = ("  " * indent)
	emit idt + "<#{node.tag}" + (" #key=\"#value\"" for key, value in node.attrs || {}) + (if empty then "/>" else ">")
	if node.content then emit that
	if node.children then
		emit "\n"
		for node.children => render &, emit, indent + 1
		emit idt
	emit (if not empty then "</#{node.tag}>" else "") + "\n"

write = (node) ->
	render root, (out = []).~push
	console.log out.join ""

##############################################################################################################################

root = X "foo"
	& "bar", {baz: "quux"}
	& "derp", "and some content"
		& "nested"
		& "nested-too"

write root

Output.xml

<foo>
  <bar baz="quux"/>
  <derp>and some content
    <nested/>
    <nested-too/>
  </derp>
</foo>