What will be the AFL version of these line of pine script

Question

src = source i.e close, per id predefined variable

a = 0.
a := per*src+(1-per)*nz(a[1],src)

Answer 1

Please try this:

a = 0;

a = per * src + (1 - per) * nz(ref(a,-1),src);

Remember about parenthesis if you need this src + (1 - per) to be calculated before this per * src