80 lines
1.8 KiB
Plaintext
80 lines
1.8 KiB
Plaintext
(*
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* Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*)
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theory Solves_Tac
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imports
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"Main"
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begin
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ML \<open>
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val ETAC_LIMIT = 5;
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(* Solve the tactic by applying the given rule, then unifying assumptions. *)
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fun solve_tac ctxt thm i goal =
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let
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(* Use "etac", but give up if there are countless unifications that
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* don't end up working. *)
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fun limited_etac thm i =
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Seq.take ETAC_LIMIT o eresolve_tac ctxt [thm] i
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in
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if Thm.no_prems thm then
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SOLVED' (resolve_tac ctxt [thm]) i goal
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else
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SOLVED' (
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limited_etac thm
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THEN_ALL_NEW (
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Goal.norm_hhf_tac ctxt THEN' Method.assm_tac ctxt)) i goal
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end
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(*
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* Return all thms available in the context.
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*
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* Clagged from "find_theorems"
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*)
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fun all_facts_of ctxt =
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let
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val local_facts = Proof_Context.facts_of ctxt;
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val global_facts = Global_Theory.facts_of (Proof_Context.theory_of ctxt);
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in
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maps Facts.selections
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(Facts.dest_static false [global_facts] local_facts @
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Facts.dest_static false [] global_facts)
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|> map snd
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end
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(* Try blindly applying every previously proven rule. *)
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fun solves_tac ctxt =
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let
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val assms =
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Proof_Context.get_fact ctxt (Facts.named "local.assms")
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handle ERROR _ => [];
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fun add_prems i = TRY (Method.insert_tac ctxt assms i);
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val all_facts = all_facts_of ctxt
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val solve_tacs = map (fn thm => solve_tac ctxt thm 1) all_facts
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in
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(add_prems THEN' assume_tac ctxt)
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ORELSE'
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SOLVED' (Subgoal.FOCUS_PARAMS (K (add_prems 1 THEN FIRST solve_tacs)) ctxt)
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end
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\<close>
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method_setup solves = "
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Scan.succeed (SIMPLE_METHOD' o solves_tac)
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" "find a previously proven fact that solves the goal"
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lemma "(A = B) = (B = A)"
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apply solves
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oops
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lemma "\<lbrakk> A \<Longrightarrow> B ; B \<Longrightarrow> A \<rbrakk> \<Longrightarrow> A = B"
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apply solves
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oops
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end
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