src/HOL/ex/sledgehammer_tactics.ML

parse lambda translation option in Metis

(*  Title:      HOL/ex/sledgehammer_tactics.ML
    Author:     Jasmin Blanchette, TU Muenchen
    Copyright   2010, 2011

Sledgehammer as a tactic.
*)

signature SLEDGEHAMMER_TACTICS =
sig
  type relevance_override = Sledgehammer_Filter.relevance_override

  val sledgehammer_with_metis_tac :
    Proof.context -> (string * string) list -> relevance_override -> int
    -> tactic
  val sledgehammer_as_oracle_tac :
    Proof.context -> (string * string) list -> relevance_override -> int
    -> tactic
end;

structure Sledgehammer_Tactics : SLEDGEHAMMER_TACTICS =
struct

open Sledgehammer_Filter

fun run_atp override_params relevance_override i n ctxt goal =
  let
    val chained_ths = [] (* a tactic has no chained ths *)
    val params as {provers, relevance_thresholds, max_relevant, slicing, ...} =
      Sledgehammer_Isar.default_params ctxt override_params
    val name = hd provers
    val prover =
      Sledgehammer_Provers.get_prover ctxt Sledgehammer_Provers.Normal name
    val default_max_relevant =
      Sledgehammer_Provers.default_max_relevant_for_prover ctxt slicing name
    val is_built_in_const =
      Sledgehammer_Provers.is_built_in_const_for_prover ctxt name
    val relevance_fudge =
      Sledgehammer_Provers.relevance_fudge_for_prover ctxt name
    val (_, hyp_ts, concl_t) = ATP_Util.strip_subgoal ctxt goal i
    val ho_atp = exists (Sledgehammer_Provers.is_ho_atp ctxt) provers
    val facts =
      Sledgehammer_Filter.nearly_all_facts ctxt ho_atp relevance_override
                                           chained_ths hyp_ts concl_t
      |> Sledgehammer_Filter.relevant_facts ctxt relevance_thresholds
             (the_default default_max_relevant max_relevant) is_built_in_const
             relevance_fudge relevance_override chained_ths hyp_ts concl_t
    val problem =
      {state = Proof.init ctxt, goal = goal, subgoal = i, subgoal_count = n,
       facts = map Sledgehammer_Provers.Untranslated_Fact facts,
       smt_filter = NONE}
  in
    (case prover params (K (K "")) problem of
      {outcome = NONE, used_facts, ...} => used_facts |> map fst |> SOME
    | _ => NONE)
      handle ERROR message => (warning ("Error: " ^ message ^ "\n"); NONE)
  end

fun thms_of_name ctxt name =
  let
    val lex = Keyword.get_lexicons
    val get = maps (Proof_Context.get_fact ctxt o fst)
  in
    Source.of_string name
    |> Symbol.source
    |> Token.source {do_recover=SOME false} lex Position.start
    |> Token.source_proper
    |> Source.source Token.stopper (Parse_Spec.xthms1 >> get) NONE
    |> Source.exhaust
  end

fun sledgehammer_with_metis_tac ctxt override_params relevance_override i th =
  case run_atp override_params relevance_override i i ctxt th of
    SOME facts =>
    Metis_Tactic.metis_tac [] ATP_Translate.combinatorsN ctxt
        (maps (thms_of_name ctxt) facts) i th
  | NONE => Seq.empty

fun sledgehammer_as_oracle_tac ctxt override_params relevance_override i th =
  let
    val thy = Proof_Context.theory_of ctxt
    val xs = run_atp (override_params @ [("sound", "true")]) relevance_override
                     i i ctxt th
  in if is_some xs then Skip_Proof.cheat_tac thy th else Seq.empty end

end;