Anonymous functions are described by the following lexical definitions:

anonfn_longform  ::=  fn [parameter_list] { expression }
anonfn_shortform ::=  [parameter_list] => expression

Here are some examples of it in action:

// Example with one parameter.
var a = [ 1, 2, "foo" ];
var found = a.find( e => e is FString );
println found; // Prints "foo"

// Example with multiple parameters.
var adder = (x, y) => x + y;
var sum = adder(1, 1);
println sum; // Prints "2"

// Example with multiple expressions.
var complicated = (x, y) => (var z = x + y; z + y)
var result = complicated( 1, 2 ); 
// result has value 5

// Example of a long anonymous function.
var long = fn(x, y, z)
{
  var z = x + y;
  var a = z * z;
  return a;
};
var answer = long( 1, 2, 3 );
// answer has value 9