I/O — post, warn, report

CL++	Luau	Use
post(...)	print(...)	normal output
warn(...)	warn(...)	recoverable problems
report(...)	error(...)	stop the thread

post("ok");
warn("careful");
report("failed");

Legacy C++ streams still parse: cout << "hi" << endl — each << is another argument, endl ends the line. Prefer post.

There is no scanf. Game data comes from Instances, DataStores (via Cluaupp/DataService), and signals.

See Builtins. Next: Roblox instances.