ref: 433357fe9fd4e99c70c780a0204244f5fd618cf2 dir: /lib/std/slfill.myr/
pkg std = generic slfill : (sl : @a[:], v : @a -> @a[:]) ;; generic slfill = {sl, v for var i = 0; i < sl.len; i++ sl[i] = v ;; -> sl }