Wrote this to reduce boilerplate when calling a function with a nullable parameter. Language is Dart. I like how concise it is but it feels weird to override []. Would you be okay with this?

extension CallMaybe<R, T> on R Function(T t) {  
  R? callMaybe(T? t) => switch (t) {  
    null => null,  
    T t => this(t),  
  };  

  R? operator [](T? t) => callMaybe(t);  
}  

void example() {  
  int? n;  
  math.sqrt[n];  
}
  • HelloRoot@lemy.lolEnglish
    12·
    2 days ago

    overwriting [] seems like readability nightmare.

    Won’t something like this work more clearly?

    extension NullCall<T> on T? {
  R? let<R>(R Function(T) f) => this == null ? null : f(this as T);
}

void example() {  
  int? n;  
  n.let(math.sqrt);
}

    This kind of immitates Kotlin let.

  • 6nk06@sh.itjust.works
    121·
    2 days ago

    I wouldn’t use this and most people will forget that it exists. Most of the time you have do use the language and avoid hacks like that.

    Don’t you have alternatives in Dart?

    • Lojcs@piefed.socialOPEnglish
      3·
      2 days ago

      I don’t think so, the null aware operator doesn’t rescue the nullable out of the parameter list.

  • FishFace@piefed.socialEnglish
    3·
    2 days ago

    Don’t overload things if the semantics don’t match. You’re not accessing something in a container; you’re calling a function.

  • Kissaki@programming.devEnglish
    3·
    2 days ago

    So you’re using [] as an alternative function call syntax to (), usable with nullable parameters?

    What’s the alternative? let x = n is null ? null : math.sqrt(n);?

    In principle, I like the idea. I wonder whether something with a question mark would make more sense, because I’m used to alternative null handling with question marks (C#, ??, ?.ToString(), etc). And I would want to see it in practice before coming to an early conclusion on whether to establish as a project principle or not.

    math.sqrt?() may imply the function itself may be null. (? ) for math.sqrt(?n)? 🤔

    I find [] problematic because it’s an index accessor. So it may be ambiguous between prop or field indexed access and method optional param calls. Dunno how that is in Dart specifically.

    • Lojcs@piefed.socialOPEnglish
      1·
      2 days ago

      Yeah pretty much as you said. I tried overriding ?[] to make it more clear but apparently ? operators can’t be overriden.

      I think I’ll go for .callMaybe()