anchor.diff:        :writer/begin-block! writer/begin-block!
         :writer/next-block!  writer/next-block!
         :writer/end-block!   writer/end-block!
  -      :add-emitter!        nil ;; TODO: Add add-emitter!
  +      :add-emitter!        (lambda () (fail! "add-emitter! is not yet implemented")) ;; TODO: Add add-emitter!
         :emit-node           lua/expression
         :emit-block          lua/block
   
  
positive.code: 
  (defun create-plugin-state (compiler)
    (let* [(logger (.> compiler :log))
           (warnings (.> compiler :warnings))
           (optimise (.> compiler :optimise))
  
  
negative.code:          (emit       '())]
      (const-struct
        ;; backend.lisp
        :add-categoriser!    (lambda () (fail! "add-categoriser! is not yet implemented")) ;; TODO: Add add-categoriser!
        :categorise-node     categories/visit-node
        :categorise-nodes    categories/visit-nodes
        :cat                 categories/cat
  