Sort-of Y-combinator in AutoIt, possible to do better?

[AutoXenon 3]

While AutoIt does treat function as first-class variables and can be passed/returned, it does not allow creation of anonymous function, so it is not possible to do partial application.

I could sort-of create a Y operator that takes two arguments, but that's not quite the same as sequential application:

 

; Local $factorial = Y(fac) ; does not work as autoit is eagerly evaluated and do not allow anonymous function definition
Local $result = Y(fac,6)

msgbox(0,"",Y(fac,6))

func fac($func, $num)
     return $num > 1 ? $num*$func($func,$num-1) : 1
endfunc

func Y($func,$arg)
     return $func($func,$arg)
endfunc

 

I'm wondering if it's possible to do better using Eval() or Execute(), but they are effectively just inline macros and do not allow for parameter substitution. Perhaps wrapping Eval into a string interpreter may do?