It's definitely SOC. You're pretty much correct in your interpretation, too. You "purify" the core of your code by asking it to merely construct a data structur

It's definitely SOC. You're pretty much correct in your interpretation, too. You "purify" the core of your code by asking it to merely construct a data structure which represents an impure program. When that pure core code produces the data structure your "run-time system" outside of it executes the program and produces side effects. If you look at another comment I left on this thread you'll see one implementation of this. While it's very complex, it does have a very nice interpretation of this system as the "RTS" and the "pure data structure" working as co-routines, passing control back and forth between one another.