[CS3 & AS2] Using Data Instead of Derivation to Refine Behavior in AS2?

[clc2007]

I'm working on my first AS2 project and could use some advice. I'm trying to create two types of objects, a soldier and a villager, using a shared NPC class:

 
class ObjNpc extends MovieClip
{
 public function onLoad()
 {
  trace(_level.legalStateNames); // this is the list of legal states
 }
 // state machine code follows...
}

The ObjNpc class will know how to handle three states -- "Idle," "Fight," and "Run" -- but I want soldiers to never enter the "Run" state and villagers to never enter the "Fight" state.

Also, I want to create the soldier and villager objects in separate flash files, which will be loaded into the scene at runtime.

So, the Soldier.FLA and Villager.FLA files will each contain a movie clip that derives from the ObjNpc class, but how can I specify their list of "legal" states without deriving a separate class for each one?

This seems like a reasonable place to use component properties, using strings like "Idle;Fight" and "Idle;Run," but for various reasons I can't use components on this project. I also can't use anything but AS2.

I tried adding a line to each object's flash file in frame 0, like this:

// Soldier.FLA contains this line of code in frame 0:
_level.legalStateNames = [ "Idle", "Fight" ];

// Villager.FLA contains this line of code in frame 0:
_level.legalStateNames = [ "Idle", "Run" ];

This approach won't work if a scene contains both a soldier and a villager, because the second object to load will overwrite _level.legalStateNames, so both NPCs will end up sharing the same state table.

Is there any way to specify data like this in a FLA file? I really don't want to make separate classes for each type, since their behaviors are so close. Component properties seem like a natual fit, except I can't use them for other reasons. Are there any other options?

Thanks!

[scottgroovez]

You said you don't want separate classes as they are so close, this is where inheritance would fit in. You'd build the main class with the common properties/methods and then extend from this your soldier and villager class. These two classes would overwrite or add properties & methods for the differing functionality.

If you don't want to sub-class then you could add Boolean properties to your ObjNpc class that switch on/off available states. Something like canFight, canIdle, canRun. Then when you initialise the instance you can activate what ever states that particular NPC has.

First method is better though.