I know. I was trying it the other way around, aliasing the part that isn't being sliced. That's why I didn't use "foo" and "bar" as the OP did -- I was experimenting, trying to understand the problem, not just the narrow question asked. It's not clear whether the issue is a user interface one -- trying to transparently provide the data array to a user to manipulate without impacting other parameters -- or a design one -- easier manipulation of separate of data and parameters sections behind the scenes without having to re-calculate offsets repeatedly. If the goal is providing the data as a slice, what I showed clearly doesn't do the trick.

If the data section is what has to be aliased, then I don't think it's possible with this technique without an explicit synchronization step before each access to the master to check whether the alias has been spliced and updating the master accordingly. Without knowing the precise application, it's impossible to guess what would offer better performance.

In the final analysis, I'm hard pressed to imagine that these kinds of workarounds are better than just leaving the object hash-based and keeping separate data and parameters entries.

Just brainstorming, however -- another way to separate the data and parameters while using an array-based object would be to use an inside-out object. Let the blessed reference be of the data array, put all the parameters in static hashes indexed off the memory address of the data array and use accessors to read/write the parameters. Of course, then there's all the overhead and complexity of inside-out objects, thread-safety and CLONE issues, and so on. Again, might not be worth it.