New feature wanted

[seifalmotaz]

Hi.
I know that there is a Function.apply method that works just like the main function.
I have an idea to make a new function let's say Function.prepare that prepare the function to be called then calls the function later.
Example:

void example(String str) {
      print(str)
}

void main() {
      var preparedFunction = Function.prepare(example, ['hello world']);
      //  ... do some code then
      preparedFunction.call(); // or preparedFunction.apply();
}

[julemand101]

How is this different from doing:

void example(String str) {
  print(str);
}

void main() {
  var preparedFunction = () => example('hello world');
  //  ... do some code then
  preparedFunction(); // hello world
}

[natebosch]

@julemand101 - It's a little different in that Function.apply unwraps a List into the individual arguments. It works to specialize to the argument shape in this example - and that's what I'd do in most cases.

@seifalmotaz - If you do need to handle functions with unknown arity or argument type (I'd avoid this if you can) you can wrap Function.apply. This is not functionality we'll include directly in the SDK.

Object? Function() applyArguments(Function f, List<Object?> args) =>
    () => Function.apply(f, args);

void example(String str) {
  print(str);
}

void main() {
  var preparedFunction = applyArguments(example, ['hello world']);
  //  ... do some code then
  preparedFunction();
}

For more discussion around feature requests fo language level support for partial application, see dart-lang/language#351