src/HOL/Tools/Sledgehammer/sledgehammer_try0.ML

more work on Z3 Isar proofs

(*  Title:      HOL/Tools/Sledgehammer/sledgehammer_try0.ML
    Author:     Jasmin Blanchette, TU Muenchen
    Author:     Steffen Juilf Smolka, TU Muenchen

Try replacing calls to metis with calls to other proof methods in order to
speed up proofs, eliminate dependencies, and repair broken proof steps.
*)

signature SLEDGEHAMMER_TRY0 =
sig
  type isar_proof = Sledgehammer_Proof.isar_proof
  type preplay_interface = Sledgehammer_Preplay.preplay_interface

  val try0 : Time.time -> preplay_interface -> isar_proof -> isar_proof
end;

structure Sledgehammer_Try0 : SLEDGEHAMMER_TRY0 =
struct

open Sledgehammer_Util
open Sledgehammer_Proof
open Sledgehammer_Preplay

val variant_methods = [SimpM, AutoM, ArithM, FastforceM, BlastM, ForceM, MetisM]

fun variants_of_step (Let _) = raise Fail "Sledgehammer_Try0: variants_of_step"
  | variants_of_step (Prove (qs, xs, l, t, subproofs, (facts, meth))) =
    variant_methods
    |> remove (op =) meth
    |> map (fn meth' => Prove (qs, xs, l, t, subproofs, (facts, meth')))

val slack = seconds 0.05

fun try0_step _ _ (step as Let _) = step
  | try0_step preplay_timeout
      ({preplay_quietly, get_preplay_time, set_preplay_time, ...} : preplay_interface)
      (step as Prove (_, _, l, _, _, _)) =
    let
      val timeout =
        (case get_preplay_time l of
          (true, _) => preplay_timeout
        | (false, t) => Time.+ (t, slack))

      fun try_variant variant =
        (case preplay_quietly timeout variant of
          (true, _) => NONE
        | time as (false, _) => SOME (variant, time))
    in
      (case Par_List.get_some try_variant (variants_of_step step) of
        SOME (step, time) => (set_preplay_time l time; step)
      | NONE => step)
    end

val try0 = map_isar_steps oo try0_step

end;