/**
         * Returns the matching value, or null.
         */
        public EnvVar get(StringValue key)
        {
            EnvVar envVar = _extMap.get(key);

            if (envVar == null)
            {
                int id = _intMap.get(key);

                if (id >= 0 && _values[id] != null)
                {
                    Var var = new Var();
                    // var.setGlobal();

                    envVar = new EnvVarImpl(var);
                    _extMap.put(key, envVar);

                    Env env = Env.getCurrent();

                    Value value = _values[id].copy(env);

                    envVar.set(value);
                }
            }

            return(envVar);
        }
        private EnvVar getEnvVar()
        {
            Env env = Env.getCurrent();

            EnvVar [] globals = env.getGlobalList();

            if (globals[_id] == this)
            {
                EnvVar var = new EnvVarImpl(new Var());

                var.set(_value.copy(env));

                globals[_id] = var;
            }

            return(globals[_id]);
        }