This change restricts the action "put obj1 on obj2" so that obj2 must have nothing over it as a pre-requisite.
Because the goal is defined as a stack (e.g., 2 on 1, 3 on 2, etc.), this change does not affect the goal itself. However, this change affects the Goal Compiler, which will now represent the new pre-requisites in the sub-goals explicitly.
This change restricts the action "put obj1 on obj2" so that obj2 must have nothing over it as a pre-requisite.
Because the goal is defined as a stack (e.g., 2 on 1, 3 on 2, etc.), this change does not affect the goal itself. However, this change affects the Goal Compiler, which will now represent the new pre-requisites in the sub-goals explicitly.
See also https://github.com/robotology/poeticon/pull/201/commits/642bac6ec9a9170adf2ffb9d2de9fe3d8f0774ec
Thanks @AlexAntn