As far as I understand, TCO (or PTC?) gives you "structured goto", i.e something that would be a pain to write as a loop, won't either mess up the state/scope,

As far as I understand, TCO (or PTC?) gives you "structured goto", i.e something that would be a pain to write as a loop, won't either mess up the state/scope, but still achieve that "loop speed" without stressing the stack.