SDQL primitives

• Manipulation of node-lists
  • node-list?
  • node-list-empty?
  • node-list-first
  • node-list-rest
  • node-list
  • node-list=?
• Manipulation of named-node-lists
  • named-node-list?
  • named-node
  • named-node-list-names
  • named-node-list-normalize