(* Title: HOL/Tools/Sledgehammer/sledgehammer_isar.ML Author: Jasmin Blanchette, TU Muenchen Author: Steffen Juilf Smolka, TU Muenchen
Isar proof reconstruction from ATP proofs.
*)
signature SLEDGEHAMMER_ISAR = sig type atp_step_name = ATP_Proof.atp_step_name type ('a, 'b) atp_step = ('a, 'b) ATP_Proof.atp_step type'a atp_proof = 'a ATP_Proof.atp_proof type stature = ATP_Problem_Generate.stature type one_line_params = Sledgehammer_Proof_Methods.one_line_params
val trace : bool Config.T
type isar_params = bool * (stringoption * stringoption * stringlist) * Time.time * real option * bool * bool
* (term, string) atp_step list * thm
val proof_text : Proof.context -> bool -> booloption -> bool -> (unit -> isar_params) -> int ->
one_line_params -> string val abduce_text : Proof.context -> term list -> string end;
open ATP_Util open ATP_Problem open ATP_Problem_Generate open ATP_Proof open ATP_Proof_Reconstruct open Sledgehammer_Util open Sledgehammer_Proof_Methods open Sledgehammer_Isar_Proof open Sledgehammer_Isar_Preplay open Sledgehammer_Isar_Compress open Sledgehammer_Isar_Minimize
val trace = Attrib.setup_config_bool \<^binding>\<open>sledgehammer_isar_trace\<close> (K false)
val e_definition_rule = "definition" val e_skolemize_rule = "skolemize" val leo2_extcnf_forall_neg_rule = "extcnf_forall_neg" val satallax_skolemize_rule = "tab_ex" val vampire_choice_axiom_rule = "choice_axiom" val vampire_skolemisation_rule = "skolemisation" val veriT_la_generic_rule = "la_generic" val veriT_simp_arith_rule = "simp_arith" val veriT_skolemize_rules = Lethe_Proof.skolemization_steps val z3_skolemize_rule = Z3_Proof.string_of_rule Z3_Proof.Skolemize val z3_th_lemma_rule_prefix = Z3_Proof.string_of_rule (Z3_Proof.Th_Lemma "") val zipperposition_cnf_rule = "cnf"
fun is_ext_rule rule = (rule = leo2_extcnf_equal_neg_rule) val is_maybe_ext_rule = is_ext_rule orf String.isPrefix satallax_tab_rule_prefix
val is_symbol_introduction_rule = member (op =) symbol_introduction_rules fun is_arith_rule rule = String.isPrefix z3_th_lemma_rule_prefix rule orelse rule = veriT_simp_arith_rule orelse
rule = veriT_la_generic_rule
fun raw_label_of_num num = (num, 0)
fun label_of_clause [(num, _)] = raw_label_of_num num
| label_of_clause c = (space_implode "___" (map (fst o raw_label_of_num o fst) c), 0)
fun add_global_fact ss = apsnd (union (op =) ss)
fun add_fact_of_dependency [(_, ss as _ :: _)] = add_global_fact ss
| add_fact_of_dependency names = apfst (insert (op =) (label_of_clause names))
fun add_line_pass1 (line as (name, role, t, rule, [])) lines = (* No dependencies: lemma (for Z3), fact, conjecture, or (for Vampire) internal facts or
definitions. *) if role = Conjecture orelse role = Negated_Conjecture then
line :: lines elseif t aconv \<^prop>\<open>True\<close> then map (replace_dependencies_in_line (name, [])) lines elseif role = Definition orelse role = Lemma orelse role = Hypothesis
orelse is_arith_rule rule then
line :: lines elseif role = Axiom then
lines (* axioms (facts) need no proof lines *) else map (replace_dependencies_in_line (name, [])) lines
| add_line_pass1 line lines = line :: lines
fun add_lines_pass2 res [] = rev res
| add_lines_pass2 res ((line as (name, role, t, rule, deps)) :: lines) = let fun normalize role =
role = Conjecture ? (HOLogic.dest_Trueprop #> s_not #> HOLogic.mk_Trueprop)
val norm_t = normalize role t val is_duplicate = exists (fn (prev_name, prev_role, prev_t, _, _) =>
(prev_role = Hypothesis andalso prev_t aconv t) orelse
(member (op =) deps prev_name andalso
Term.aconv_untyped (normalize prev_role prev_t, norm_t)))
res
fun looks_boring () = t aconv \<^prop>\<open>False\<close> orelse length deps < 2
fun is_symbol_introduction_line (_, _, _, rule', deps') =
is_symbol_introduction_rule rule' andalso member (op =) deps' name
fun is_before_symbol_introduction_rule () = exists is_symbol_introduction_line lines in if is_duplicate orelse
(role = Plain andalso not (is_symbol_introduction_rule rule) andalso not (is_ext_rule rule) andalso not (is_arith_rule rule) andalso not (null lines) andalso looks_boring () andalso not (is_before_symbol_introduction_rule ())) then
add_lines_pass2 res (map (replace_dependencies_in_line (name, deps)) lines) else
add_lines_pass2 (line :: res) lines end
type isar_params = bool * (stringoption * stringoption * stringlist) * Time.time * real option * bool * bool
* (term, string) atp_step list * thm
val basic_systematic_methods =
[Metis_Method (NONE, NONE, []), Meson_Method, Blast_Method, SATx_Method, Argo_Method] val basic_simp_based_methods =
[Auto_Method, Simp_Method, Fastforce_Method, Force_Method] val basic_arith_methods =
[Linarith_Method, Presburger_Method, Algebra_Method]
fun isar_proof_text ctxt debug num_chained isar_proofs smt_proofs isar_params
(one_line_params as ((used_facts, (_, one_line_play)), banner, subgoal, subgoal_count)) = let val _ = if debug then writeln "Constructing Isar proof..."else ()
fun generate_proof_text () = let val (verbose, alt_metis_args, preplay_timeout, compress, try0, minimize, atp_proof0, goal) =
isar_params () in if null atp_proof0 then
one_line_proof_text one_line_params else let val systematic_methods' = insert (op =) (Metis_Method alt_metis_args) systematic_methods
fun massage_methods (meths as meth :: _) = ifnot try0 then [meth] elseif smt_proofs then insert (op =) (SMT_Method (SMT_Verit "default")) meths else meths
val (params, _, concl_t) = strip_subgoal goal subgoal ctxt val fixes = map (fn (s, T) => (Binding.name s, SOME T, NoSyn)) params val ctxt = ctxt |> Variable.set_body false |> Proof_Context.add_fixes fixes |> snd
val do_preplay = preplay_timeout <> Time.zeroTime val compress =
(case compress of
NONE => if isar_proofs = NONE andalso do_preplay then 1000.0 else 10.0
| SOME n => n)
fun is_fixed ctxt = Variable.is_declared ctxt orf Name.is_skolem fun introduced_symbols_of ctxt t =
Term.add_frees t [] |> filter_out (is_fixed ctxt o fst) |> rev
fun get_role keep_role ((num, _), role, t, rule, _) = if keep_role role then SOME ((raw_label_of_num num, t), rule) else NONE
val trace = Config.get ctxt trace
val string_of_atp_steps = letval to_string = ATP_Proof.string_of_atp_step (Syntax.string_of_term ctxt) I in
enclose "[\n""\n]" o cat_lines o map (enclose " ""," o to_string) end
val atp_proof = atp_proof0
|> trace ? tap (tracing o prefix "atp_proof0 = " o string_of_atp_steps)
|> distinct (op =) (* Zipperposition generates duplicate lines *)
|> (fn lines => fold_rev add_line_pass1 lines [])
|> add_lines_pass2 []
|> trace ? tap (tracing o prefix "atp_proof = " o string_of_atp_steps)
val conjs =
map_filter (fn (name, role, _, _, _) => if member (op =) [Conjecture, Negated_Conjecture] role then SOME name else NONE)
atp_proof val assms = map_filter (Option.map fst o get_role (curry (op =) Hypothesis)) atp_proof
fun add_lemma ((label, goal), rule) ctxt = let val (obtains, proof_methods) =
(if is_symbol_introduction_rule rule then (introduced_symbols_of ctxt goal, skolem_methods) elseif is_arith_rule rule then ([], arith_methods) else ([], rewrite_methods))
||> massage_methods val prove = Prove {
qualifiers = [],
obtains = obtains,
label = label,
goal = goal,
subproofs = [],
facts = ([], []),
proof_methods = proof_methods,
comment = ""} in
(prove, ctxt |> not (null obtains) ? (Variable.add_fixes (map fst obtains) #> snd)) end
val axioms = axioms_of_refute_graph refute_graph conjs
val tainted = tainted_atoms_of_refute_graph refute_graph conjs val is_clause_tainted = exists (member (op =) tainted) val steps =
Symtab.empty
|> fold (fn (name as (s, _), role, t, rule, _) =>
Symtab.update_new (s, (rule, t
|> (if is_clause_tainted [name] then
HOLogic.dest_Trueprop
#> role <> Conjecture ? s_not
#> fold exists_of (map Var (Term.add_vars t []))
#> HOLogic.mk_Trueprop else
I))))
atp_proof
fun is_referenced_in_step _ (Let _) = false
| is_referenced_in_step l (Prove {subproofs, facts = (ls, _), ...}) =
member (op =) ls l orelse exists (is_referenced_in_proof l) subproofs and is_referenced_in_proof l (Proof {steps, ...}) = exists (is_referenced_in_step l) steps
(* We try to introduce pure lemmas (not "obtains") close to where
they are used. *) fun insert_lemma_in_step lem
(step as Prove {qualifiers, obtains, label, goal, subproofs, facts = (ls, gs),
proof_methods, comment}) = letval l' = the (label_of_isar_step lem) in if member (op =) ls l' then
[lem, step] else letval refs = map (is_referenced_in_proof l') subproofs in if length (filter I refs) = 1 then
[Prove {
qualifiers = qualifiers,
obtains = obtains,
label = label,
goal = goal,
subproofs =
map2 (fn false => I | true => insert_lemma_in_proof lem) refs subproofs,
facts = (ls, gs),
proof_methods = proof_methods,
comment = comment}] else
[lem, step] end end and insert_lemma_in_steps lem [] = [lem]
| insert_lemma_in_steps lem (step :: steps) = ifnot (null (obtains_of_isar_step lem))
orelse is_referenced_in_step (the (label_of_isar_step lem)) step then
insert_lemma_in_step lem step @ steps else
step :: insert_lemma_in_steps lem steps and insert_lemma_in_proof lem (proof as Proof {steps, ...}) =
isar_proof_with_steps proof (insert_lemma_in_steps lem steps)
val rule_of_clause_id = fst o the o Symtab.lookup steps o fst
val finish_off = close_form #> rename_bound_vars
fun prop_of_clause [(num, _)] = Symtab.lookup steps num |> the |> snd |> finish_off
| prop_of_clause names = let val lits = map (HOLogic.dest_Trueprop o snd) (map_filter (Symtab.lookup steps o fst) names) in
(caseList.partition (can HOLogic.dest_not) lits of
(negs as _ :: _, pos as _ :: _) =>
s_imp (Library.foldr1 s_conj (map HOLogic.dest_not negs),
Library.foldr1 s_disj pos)
| _ => fold (curry s_disj) lits \<^term>\<open>False\<close>) end
|> HOLogic.mk_Trueprop |> finish_off
fun maybe_show outer c = if outer andalso eq_set (op =) (c, conjs) then [Show] else []
fun isar_steps outer predecessor accum [] =
accum
|> (if tainted = [] then (* e.g., trivial, empty proof by Z3 *)
cons (Prove {
qualifiers = if outer then [Show] else [],
obtains = [],
label = no_label,
goal = concl_t,
subproofs = [],
facts = sort_facts (the_list predecessor, []),
proof_methods = massage_methods systematic_methods',
comment = ""}) else
I)
|> rev
| isar_steps outer _ accum (Have (id, (gamma, c)) :: infs) = let val l = label_of_clause c val t = prop_of_clause c val rule = rule_of_clause_id id val introduces_symbols = is_symbol_introduction_rule rule
val deps = ([], [])
|> fold add_fact_of_dependency gamma
|> is_maybe_ext_rule rule ? add_global_fact [short_thm_name ctxt ext]
|> sort_facts val meths =
(if introduces_symbols then skolem_methods elseif is_arith_rule rule then arith_methods else systematic_methods')
|> massage_methods
fun prove subproofs facts = Prove {
qualifiers = maybe_show outer c,
obtains = [],
label = l,
goal = t,
subproofs = subproofs,
facts = facts,
proof_methods = meths,
comment = ""} fun steps_of_rest step = isar_steps outer (SOME l) (step :: accum) infs in if is_clause_tainted c then
(case gamma of
[g] => if introduces_symbols andalso is_clause_tainted g andalso not (null accum) then let val fixes = introduced_symbols_of ctxt (prop_of_clause g) val subproof = Proof {fixes = fixes, assumptions = [], steps = rev accum} in
isar_steps outer (SOME l) [prove [subproof] ([], [])] infs end else
steps_of_rest (prove [] deps)
| _ => steps_of_rest (prove [] deps)) else
steps_of_rest
(if introduces_symbols then
(case introduced_symbols_of ctxt t of
[] => prove [] deps
| skos => Prove {
qualifiers = [],
obtains = skos,
label = l,
goal = t,
subproofs = [],
facts = deps,
proof_methods = meths,
comment = ""}) else
prove [] deps) end
| isar_steps outer predecessor accum (Cases cases :: infs) = let fun isar_case (c, subinfs) =
isar_proof false [] [(label_of_clause c, prop_of_clause c)] [] subinfs val c = succedent_of_cases cases val l = label_of_clause c val t = prop_of_clause c val step =
Prove {
qualifiers = maybe_show outer c,
obtains = [],
label = l,
goal = t,
subproofs = map isar_case (filter_out (null o snd) cases),
facts = sort_facts (the_list predecessor, []),
proof_methods = massage_methods systematic_methods',
comment = ""} in
isar_steps outer (SOME l) (step :: accum) infs end and isar_proof outer fixes assumptions lems infs = letval steps = fold_rev insert_lemma_in_steps lems (isar_steps outer NONE [] infs) in
Proof {fixes = fixes, assumptions = assumptions, steps = steps} end
val canonical_isar_proof =
refute_graph
|> trace ? tap (tracing o prefix "Refute graph:\n" o string_of_refute_graph)
|> redirect_graph axioms tainted bot
|> trace ? tap (tracing o prefix "Direct proof:\n" o string_of_direct_proof)
|> isar_proof true params assms lems
|> postprocess_isar_proof_remove_show_stuttering
|> postprocess_isar_proof_remove_unreferenced_steps I
|> relabel_isar_proof_canonically
val ctxt = ctxt |> enrich_context_with_local_facts canonical_isar_proof
val preplay_data = Unsynchronized.ref Canonical_Label_Tab.empty
val _ = fold_isar_steps (fn meth =>
K (set_preplay_outcomes_of_isar_step ctxt preplay_timeout preplay_data meth []))
(steps_of_isar_proof canonical_isar_proof) ()
fun str_of_preplay_outcome outcome = if Lazy.is_finished outcome then string_of_play_outcome (Lazy.force outcome) else"?" fun str_of_meth l meth =
string_of_proof_method [] meth ^ " " ^
str_of_preplay_outcome
(preplay_outcome_of_isar_step_for_method (!preplay_data) l meth) fun comment_of l = map (str_of_meth l) #> commas
fun trace_isar_proof label proof = if trace then
tracing (timestamp () ^ "\n" ^ label ^ ":\n\n" ^
string_of_isar_proof ctxt subgoal subgoal_count
(comment_isar_proof comment_of proof) ^ "\n") else
()
fun comment_of l (meth :: _) =
(case (verbose,
Lazy.force (preplay_outcome_of_isar_step_for_method (!preplay_data) l meth)) of
(false, Played _) => ""
| (_, outcome) => string_of_play_outcome outcome)
val (play_outcome, isar_proof) =
canonical_isar_proof
|> tap (trace_isar_proof "Original")
|> compress_isar_proof ctxt compress preplay_timeout preplay_data
|> tap (trace_isar_proof "Compressed")
|> postprocess_isar_proof_remove_unreferenced_steps
(do_preplay ? keep_fastest_method_of_isar_step (!preplay_data)
#> minimize ? minimize_isar_step_dependencies ctxt preplay_data)
|> tap (trace_isar_proof "Minimized")
|> `(if do_preplay then preplay_outcome_of_isar_proof (!preplay_data) else K (Play_Timed_Out Time.zeroTime))
||> (comment_isar_proof comment_of
#> chain_isar_proof
#> kill_useless_labels_in_isar_proof
#> relabel_isar_proof_nicely
#> rationalize_obtains_in_isar_proofs ctxt) in
(case (num_chained, add_isar_steps (steps_of_isar_proof isar_proof) 0) of
(0, 1) =>
one_line_proof_text
(if is_less (play_outcome_ord (play_outcome, one_line_play)) then
(case isar_proof of
Proof {steps = [Prove {qualifiers = [Show], facts = (_, gfs),
proof_methods = meth :: _, ...}], ...} => let val used_facts' =
map_filter (fn s => ifexists (fn (p, (sc, _)) => content_of_pretty p = s andalso
sc = Chained) used_facts then
NONE else
SOME (Pretty.str s, (Global, General))) gfs in
((used_facts', (meth, play_outcome)), banner, subgoal, subgoal_count) end
| _ => one_line_params) else
one_line_params) ^
(if isar_proofs = SOME truethen"\n(No Isar proof available)"else"")
| (_, num_steps) => let val msg =
(if verbose then [string_of_int num_steps ^ " step" ^ plural_s num_steps] else []) @
(if do_preplay then [string_of_play_outcome play_outcome] else []) in
one_line_proof_text one_line_params ^
(if isar_proofs <> NONE orelse (case play_outcome of Played _ => true | _ => false) then "\n\nIsar proof" ^ (commas msg |> not (null msg) ? enclose " ("")") ^ ":\n" ^
Active.sendback_markup_command
(string_of_isar_proof ctxt subgoal subgoal_count isar_proof) else "") end) end end in if debug then
generate_proof_text () else
(casetry generate_proof_text () of
SOME s => s
| NONE =>
one_line_proof_text one_line_params ^
(if isar_proofs = SOME truethen"\nWarning: Isar proof construction failed"else"")) end
fun isar_proof_would_be_a_good_idea (_, play) =
(case play of
Played _ => false
| Play_Timed_Out time => time > Time.zeroTime
| Play_Failed => true)
fun proof_text ctxt debug isar_proofs smt_proofs isar_params num_chained
(one_line_params as ((_, preplay), _, _, _)) =
(if isar_proofs = SOME true orelse
(isar_proofs = NONE andalso isar_proof_would_be_a_good_idea preplay) then
isar_proof_text ctxt debug num_chained isar_proofs smt_proofs isar_params else
one_line_proof_text) one_line_params
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