diff options
author | Josh Chen | 2020-05-24 20:44:33 +0200 |
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committer | Josh Chen | 2020-05-24 20:44:33 +0200 |
commit | 3ad2f03f7dbc922e2c711241146db091d193003d (patch) | |
tree | 6db26730510b119bf10dc836d21a9869ace6c416 /spartan/lib/tactics.ML | |
parent | 6f37e6b72905eff8f2c7078823e5577bc5b55eb0 (diff) |
new work on elimination tactic
Diffstat (limited to '')
-rw-r--r-- | spartan/lib/tactics.ML | 81 |
1 files changed, 62 insertions, 19 deletions
diff --git a/spartan/lib/tactics.ML b/spartan/lib/tactics.ML index c72947a..024abc1 100644 --- a/spartan/lib/tactics.ML +++ b/spartan/lib/tactics.ML @@ -4,7 +4,7 @@ General tactics for dependent type theory. *) -structure Tactics: +structure Tactics(* : sig val assumptions_tac: Proof.context -> int -> tactic @@ -18,7 +18,7 @@ val intro_tac: Proof.context -> int -> tactic val intros_tac: Proof.context -> int -> tactic val elims_tac: term option -> Proof.context -> int -> tactic -end = struct +end *) = struct (*An assumption tactic that only solves typing goals with rigid terms and judgmental equalities without schematic variables*) @@ -56,25 +56,22 @@ fun typechk_tac ctxt = let val net = Tactic.build_net ((Named_Theorems.get ctxt \<^named_theorems>\<open>typechk\<close>) @(Named_Theorems.get ctxt \<^named_theorems>\<open>intros\<close>) - @(Elim.rules ctxt)) + @(map #1 (Elim.rules ctxt))) in (resolve_from_net_tac ctxt net) i end else no_tac) in - CHANGED o REPEAT o REPEAT_ALL_NEW (known_tac ctxt ORELSE' tac) + REPEAT_ALL_NEW (known_tac ctxt ORELSE' tac) end (*Many methods try to automatically discharge side conditions by typechecking. Switch this flag off to discharge by non-unifying assumption instead.*) val auto_typechk = Attrib.setup_config_bool \<^binding>\<open>auto_typechk\<close> (K true) +fun side_cond_tac ctxt = CHANGED o REPEAT o + (if Config.get ctxt auto_typechk then typechk_tac ctxt else known_tac ctxt) + (*Combinator runs tactic and tries to discharge all new typing side conditions*) -fun SIDE_CONDS tac ctxt = - let - val side_cond_tac = - if Config.get ctxt auto_typechk then typechk_tac ctxt else known_tac ctxt - in - tac THEN_ALL_NEW (TRY o side_cond_tac) - end +fun SIDE_CONDS tac ctxt = tac THEN_ALL_NEW (TRY o side_cond_tac ctxt) local fun mk_rules _ ths [] = ths @@ -87,13 +84,11 @@ fun mk_rules _ ths [] = ths in (*Resolves with given rules, discharging as many side conditions as possible*) -fun rule_tac ths ctxt = - SIDE_CONDS (resolve_tac ctxt (mk_rules 0 [] ths)) ctxt +fun rule_tac ths ctxt = resolve_tac ctxt (mk_rules 0 [] ths) (*Attempts destruct-resolution with the n-th premise of the given rules*) -fun dest_tac opt_n ths ctxt = SIDE_CONDS (dresolve_tac ctxt - (mk_rules (case opt_n of NONE => 0 | SOME 0 => 0 | SOME n => n-1) [] ths)) - ctxt +fun dest_tac opt_n ths ctxt = dresolve_tac ctxt + (mk_rules (case opt_n of NONE => 0 | SOME 0 => 0 | SOME n => n-1) [] ths) end @@ -107,17 +102,17 @@ fun intros_tac ctxt = SUBGOAL (fn (_, i) => (*Basic elimination tactic, only uses existing type judgments from the context (performs no type synthesis)*) fun elims_tac opt_tm ctxt = case opt_tm of - NONE => SUBGOAL (fn (_, i) => eresolve_tac ctxt (Elim.rules ctxt) i) + NONE => SUBGOAL (fn (_, i) => eresolve_tac ctxt (map #1 (Elim.rules ctxt)) i) | SOME tm => SUBGOAL (fn (goal, i) => let fun elim_rule typing = let val hd = head_of (Lib.type_of_typing typing) - val opt_rl = Elim.get_rule ctxt hd + val opt_rl = Elim.lookup_rule ctxt hd in case opt_rl of NONE => Drule.dummy_thm - | SOME rl => Drule.infer_instantiate' ctxt + | SOME (rl, _) => Drule.infer_instantiate' ctxt [SOME (Thm.cterm_of ctxt tm)] rl end @@ -137,6 +132,54 @@ fun elims_tac opt_tm ctxt = case opt_tm of ORELSE' eresolve_tac ctxt candidate_rules') i end) +(* Revamped general induction/elimination *) + +(*Pushes a context/goal premise typing t:T into a \<Prod>-type*) +fun internalize_fact_tac t = + Subgoal.FOCUS_PARAMS (fn {context = ctxt, concl = raw_concl, ...} => + let + val concl = Logic.strip_assums_concl (Thm.term_of raw_concl) + val C = Lib.type_of_typing concl + val B = Thm.cterm_of ctxt (Lib.lambda_var t C) + val a = Thm.cterm_of ctxt t + (*The resolvent is PiE[where ?B=B and ?a=a]*) + val resolvent = + Drule.infer_instantiate' ctxt [NONE, NONE, SOME B, SOME a] @{thm PiE} + in + HEADGOAL (resolve_tac ctxt [resolvent]) + (*known_tac infers the correct type T inferred by unification*) + THEN SOMEGOAL (known_tac ctxt) + end) + +fun elim_tac' tms ctxt = case tms of + [] => SUBGOAL (fn (_, i) => eresolve_tac ctxt (map #1 (Elim.rules ctxt)) i) + | major::_ => SUBGOAL (fn (goal, i) => + let + val template = Lib.typing_of_term major + val facts = Proof_Context.facts_of ctxt + val prems = Logic.strip_assums_hyp goal + val types = + map (Thm.prop_of o #1) (Facts.could_unify facts template) + @ filter (fn prem => Term.could_unify (template, prem)) prems + |> map Lib.type_of_typing + in case types of + [] => no_tac + | _ => + let + val rule_insts = map ((Elim.lookup_rule ctxt) o Term.head_of) types + val rules = flat (map + (fn rule_inst => case rule_inst of + NONE => [] + | SOME (rl, idxnames) => [Drule.infer_instantiate ctxt + (idxnames ~~ map (Thm.cterm_of ctxt) tms) rl]) + rule_insts) + in + resolve_tac ctxt rules i + THEN RANGE (replicate (length tms) (typechk_tac ctxt)) 1 + end handle Option => no_tac + end) + + end open Tactics |