4 ms·

null safety: Can you provide us a reference to a working definition of the term?

• cageface 5y ago
  For example in Typescript, you can specify whether a parameter is allowed to be null in the signature of a function. If you do the compiler will make sure that you don't accidentally pass a null value to that function. function foo(x: number) { return x + 1; } let y = null; foo(y); // compiler will flag this
  • drvd 5y ago
    In Go func foo(x int) { return x + 1 } var y *int = nil foo(y) // compiler will flag thi
    • Gwypaas 5y ago
      Now add an error to foo and have x=0 as a valid return value, or even worse, having to deal differently with different errors.
    • cy_hauser 5y ago
      That wasn't the greatest example as Go doesn't really have any way to represent it. If it did it might be something like this. type MyStruct struct { Name string } var-not-nil myStruct = &MyStruct{"Hello"} // this is a "not-nil" pointer variable myStruct = nil // compiler would catch this The idea being to allow variables to hold and pass pointers to structs like now but ensure they are never nil.
• Macha 5y ago
  null/nil can only occur in scoped use cases (Option<Foo>, Foo | null, Foo?) and so the compiler can warn you when something could be missing and you don't handle it without being incredibly noisy.