# Print a node (using to_s) on a line and recustively each children indented (with two spaces)
class TreePrinterVisitor
	super Visitor
	var writer: Writer
	private var indent = 0
	redef fun visit(n)
	do
		for i in [0..indent[ do writer.write("  ")
		writer.write(n.to_s)
		writer.write("\n")
		indent += 1
		super
		indent -= 1
	end
end