ActionScript 3.0 :: Improving The Script Interpreter?

So i'm building a plugin system for my game, and i need to know actively what objects each plugin wants to use. For this, i have made a simple String interpreter. What it can do so far is separate id's and get whether a required input uses all of that kind.

my input format is like this:

Code:
IA:[param];IA[param];NN

IA is the index of all objects matching the parameter to the right of it. A is replaced by A if you want all those objects with the ID of param, or a number for a specific index.:[] tells the interpreter that what is inside the ['s is the param.the param is the string identifier that it looks for when finding objects.NN is the end sequence. this tells the engine that it doesn't need any more params.so say i had a plugin that uses the string

Code:
I2[player];IA[world];NN

the engine will loop through all objects with the ID "world" using them as the second param for the plugin's behavior, and the first will always be the 2nd "player" in the list.I can currently detect whether it wants all of a certain parameter, and what the parameter is. Now, i need to be able to find the index each param requires if it is not all. And i've tried multiple ways of doing this, but none so far have worked. What method would i use? Also, if you see anything that would kill performance in the interpreter, i would love to know, as this is called every frame.

My current code is a class with static methods called StringInterpreter, with the below code:

Code:
package Utils
{
public class ScriptInterpreter
{

[code]...