3 ms·

I interpreted this as 'don't write crappy functions taking confusing arguments'. If the function had taken 4 floating point numbers, the argument would be the s

• tialaramex 2y ago
  Sure, but booleans are the lowest hanging fruit, most programmers won't write many functions which take 3 floating point numbers and are then modified to add a fourth but they will write functions which have three flag booleans and then add a fourth. The generalization of the author's lesson is the New Type idiom. Don't use basic types like "integer" when you can invent types which correspond to the actual meaning of your values. A Duration, a FileDescriptor, a DatabaseHandle, a KeyboardScanCode. Once we do this it's obvious that if the function takes a FileDescriptor and a Duration we should not give it this KeyboardScanCode we have twice, that's clearly nonsense. Rust piles on extra value for its own New Types (as yet you cannot directly grant this to your own types although if they're enumerations they get it for free) - niches. Result<(), OwnedFd> is the same size (a single 32-bit integer) as the C int you'd have used for this purpose in a much less capable language, but since it's a Result type it has all the same ergonomics as if it was much more complicated and heavyweight than that.