Re:Avoid Else, Return Early (2013)
by contravariant on Monday March 26, 2018 @10:56AM
(#16679348)
Dijkstra's approach towards provably correct programs has changed my opinion on loops somewhat.
Among all types a 'while' loop gives the strongest mathematical guarantees. In particular it ensures a condition is true at the start of each iteration, and is false when exiting the while loop. Combining this with loop invariants leads to precise and straightforward to verify code.
Avoiding while loops to ensure an exit just seems to be sacrificing a lot of power in exchange for some pretty shaky guarantees that your loop will finish.
Although in the majority of cases where a while loop could be used you're simply iterating over some (implicit) data structure. In which case it's obviously better to make this explicit using a "for ... in" loop.
Among all types a 'while' loop gives the strongest mathematical guarantees. In particular it ensures a condition is true at the start of each iteration, and is false when exiting the while loop. Combining this with loop invariants leads to precise and straightforward to verify code.
Avoiding while loops to ensure an exit just seems to be sacrificing a lot of power in exchange for some pretty shaky guarantees that your loop will finish.
Although in the majority of cases where a while loop could be used you're simply iterating over some (implicit) data structure. In which case it's obviously better to make this explicit using a "for ... in" loop.