| Enumerator | 
|---|
| GV_OP_NOP  | Ignore.  
 | 
| GV_OP_SET  | Set the internal value to the parameter value. (The constant node uses this.)  
 | 
| GV_OP_DROP  | An atom has been dropped over the node.  
 | 
| GV_OP_DROP_IN_BODY  | An atom has been dropped over the body of the node.  
 | 
| GV_OP_DROP_IN_INDOCK  | An atom has been dropped in the inport area of the node.  
 | 
| GV_OP_DROP_IN_OUTDOCK  | An atom has been dropped in the outport area of the node.  
 |