Sorry to be a damp squib, but please be very careful what you try to use lvalue refs for.

They have one or two uses for which they're indispensible, mostly to do with large volumes of fixed record length, usually binary data.

There are other uses, but they can easily start to produce confusing results if you make small mistakes, and that is when you know what you have, and are dealing with. I think blessing them and passing them to others to manipulate is not a good idea.

One of the problems is that they will allow you to replace a substring with either more or less characters than it originally held (just as substr will), but once you have done this, working out what substring the lvref now points to is confusing and will rarely be what you will expect. This is going to get better at some point in the future.

However, if you have two or more lvref pointing to the same string, and one is used to alter the length of overall string, then the substring addressed by the other may or may not change, sometimes in quite radical and confusing ways, depending upon the relationship between the original two. This is not going to change.

Best saved for very localised use, for very specific purposes I think.