Official Dart docs is sometimes too simple to provide ultimate answers for various language questions. I discoverd an alternative syntax for named lambda here and here. In Dart,

(args) => expr

is the shorthand for

(args) { 
  return expr 
}

So the Lambda-style (C++11) names variable by assigning it to a messy functor type (inferred with var in Dart and auto in C++11):

var f = (args) => expr

Which can also be rewritten using C-style function pointer-like declaration except

1. the body expr is included (which is not allowed in C),
2. return must be explicit in curly braces block.
3. arrow notation => takes whatever the expr evaluates to (which can be null for statements like print)
4. it’s simply the function name f in Dart instead of pointer (*f) in C

[optional return type] f(args) { 
  return expr;
}

which can be simplified with the arrow operator

[optional return type] f(args) => { expr }