Generate String interpolator

[Andrea Peruffo]

A little problem with parenthesis...

I have to generate a string interpolation syntax like 

s"$x hello $y"

and I write it like:

REF("s") APPLY(LIT("$x hello $y")) 

but predictably it result in:

s("$x hello $y")

that doesn't work... 

any way to achieve the result?

Thanks in advance!

Andrea