ML-like datatype decalaration facility. Axiomatic.
let
fun tac ss = resolve_tac(prems_of_ss ss) ORELSE' asm_simp_tac ss;
val ss = set_prove_tac(HOL_ss addsimps [Suc_lessD],tac)
in prove_goal Nat.thy "!!x. Suc(Suc(Suc(x)))<y ==> x<y"
(fn _ => [asm_simp_tac ss 1])
end;