Consider assembly or basic, which use a lot of goto-statements. It can get very ugly trying to fit some arbitrary goto's into the more structured loops and if-s

Consider assembly or basic, which use a lot of goto-statements. It can get very ugly trying to fit some arbitrary goto's into the more structured loops and if-statements we're accustomed to. There was a lot of work around equivalance of control flow between goto/conditional branch instructions/unconditional branch instructions and "while programs" in the 70's that showed there's actually a limited variety of control flow patterns, and while programs can be made equivalent. I think the result of this is the nowadays presence of break/continue loop constructs in most languages. Maybe this is a folk theorem, I don't recall really.