class ActionDispatch::Journey::Visitors::String

def binary(node)
  [visit(node.left), visit(node.right)].join
end

def nary(node)
  node.children.map { |c| visit(c) }.join '|'
end

def terminal(node)
  node.left
end

def visit_GROUP(node)
  "(#{visit(node.left)})"
end