I don’t know if this is possible in the programming language in question, but you probably don’t want any programs that use some kind of trickery to retroactively change what they chose in previous rounds. Or implement anthropic computing with the Scheme equivalents of fork() and exit(). (Before doing anything, call fork() to make a copy of the universe. If you don’t like the result, call exit() to destroy it.)
I don’t know if this is possible in the programming language in question, but you probably don’t want any programs that use some kind of trickery to retroactively change what they chose in previous rounds. Or implement anthropic computing with the Scheme equivalents of fork() and exit(). (Before doing anything, call fork() to make a copy of the universe. If you don’t like the result, call exit() to destroy it.)