Optional arguments without ? identifier

Question

In the Haxe 3 manual at http://haxe.org/manual/types-function-default-values.html, we have static function test(?i = 12, s = "bar").

Why isn't it static function test(?i = 12, ?s = "bar") or static function test(i = 12, s = "bar")?

Possible duplicate of [Meaning of question mark operator '?' before arguments in Haxe](https://stackoverflow.com/questions/31914614/meaning-of-question-mark-operator-before-arguments-in-haxe) — Gama11, Feb 02 '19 at 12:21

score 2 · Accepted Answer · answered Sep 07 '15 at 05:09

Actually, there's a subtle difference between ?i=1 and i=1:

function test(?i=1):String is of type Null<Int> -> String
function test(i=1):String is of type Int -> String

While ?i indicates an optional argument – and that always implies nullability – i=1 indicates a default value and should eliminate the need for a Null<T> box.

See Optional Arguments and Nullability and an example.

Optional arguments without ? identifier

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