i:Id, ds:x:Id fp Type, da:k:Knd fp Type, A:ecl(ds;da), k:Knd, l:IdLnk, tg:Id, n:,
f:(State(ds)Valtype(da;k)da(rcv(l,tg))?Void), es:ES.
source(l) = i (@i[[A;k sends on l with tag tg [s,v.f(s,v)], at marker n]]
(
((es-decls(es;i;ds;da)
(( with decls ds (( with decls da (( sends on l from e (( include if kind(e) = k action[[An]][es-init(es;e);e] [<tg,f((state when e),val(e))>]
(( include else nil fi
(( and only these for tags in [tg]))