protected int addLR0State(AssemblyParseState state) {
		int num = states.indexOf(state);
		if (num != -1) {
			return num;
		}
		states.add(state);
		return states.size() - 1;
	}
Add a newly-constructed LR0 state, and return it's assigned number

<p>
If the state already exists, this just returns its previously assigned number

@param state the newly-constructed state
@return the assigned number
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/app/plugin/assembler/sleigh/parse/AssemblyParser.java