Lambda

lambda ::= <lambda_parameters> -> <expression>
post_lambda ::= { [<lambda_parameters> -> ]
    <expression>
    <expression>
    ...
}
lambda_parameters ::= <lambda_parameter> [, <lambda_parameter> ...]
lambda_parameter ::= name [ : <datatype>]

array.map{item -> item + 1}
array.map(_ + 1) //The same

array.fold(0){result, item -> result + item} //Sum
array.fold(0, _1 + _2) //The same

val f : (int, int) -> int = a : int, b : int -> a + b //You can omit the datatype