===== How to register and achieve a new goal =====

==== A plan for a new goal ====

Let's assume we wanna write a plan to achieve a new goal, e.g. to flip a pancake. Best practice is to put this plan into one of the source-files of a plan library, e.g. cram_plan_library:


<code lisp>
(def-goal (achieve (flip-pancake ...))
  (with-designators ((action-desig 
                       (action `((to flip))))
                     ...)
    ...
    (perform action)))
</code>

If you want other packages to also use this plan, export the goal-symbol in the package.lisp of the your plan library. Make sure to also export all designator properties used in your plan:

<code lisp>
(desig-props:def-desig-package cram-plan-library
 ...
 (:export #:...
          #:flip-pancake
          ...)
 (:desig-properties #:to #:flip ...))
</code>

Catch #1: If you one of your manipulation process modules, e.g. the pr2_manipulation_process_module, uses the same designator properties it also has to export the same properties. I (Georg) do not understand why but Jan says this necessary for them to talk about the same symbol.

Catch #2: You also need to export the goal-symbol, i.e. flip-pancake, from the package cram_plan_knowledge! The reason for this was not clear at the time of writing... Thus, yuo also need to add #:flip-pancake to package.lisp of cram_plan_library. Otherwise you will get a warning like this when trying to achieve flip-pancake:

<code>
WARNING:
   Trying to prove goal (FLIP-PANCAKE
                         #<OBJECT-DESIGNATOR ((TYPE PANCAKE))
                           {100926AF61}>) with undefined functor CRAM-PLAN-LIBRARY:FLIP-PANCAKE.
</code>
==== How to use/achieve the new plan ====

You can now try to achieve your new goal like this:

<code lisp>
(top-level
  (cpm:with-process-modules-running
      (pr2-manipulation-process-module)
    (achieve `(flip-pancake))))
</code>

You need to make sure that cram_environment_representation is loaded (either in your package that uses cram_plan_library or in your REPL). Otherwise (holds ...) will not be known.