Got the idea reading <a href=”http://www.peterjoel.com/blog/index.php?archive=2004_01_01_archive.xml#107436735658229384″>Peter Hall’s suggestion</a> for new file formats based on calling the Flash Player the Flash Virtual Machine.
When a symbol is exported in a SWF, that SWF now exposes that symbol, by linkage name, to whatever SWF has pointer to it. In reverse, when a symbol is imported for runtime sharing, that SWF now points that symbol to the SWF it’s assigned to get the symbol from.
Now, it’d be phat as nuts if we could do at least part of the above dynamically. The only new requirement would be “symbol creation”. Currently, we can create instances on the fly, but the “classes” they are derived from are hardcoded into the SWF; the symbol. This ability would allow some pretty neat abilities at runtime.