public void defineLexerAction(ActionAST actionAST) {
		actionIndex = g.lexerActions.size();
		if ( g.lexerActions.get(actionAST)==null ) {
			g.lexerActions.put(actionAST, actionIndex);
		}
	}
Lexer actions are numbered across rules 0..n-1
tool/src/org/antlr/v4/tool/Rule.java