(* Author: L C Paulson and Claire Quigley, Cambridge University Computer Laboratory *) (***************************************************************************) (* Code to deal with the transfer of proofs from a prover process *) (***************************************************************************) signature RES_RECONSTRUCT = sig val chained_hint: string val fix_sorts: sort Vartab.table -> term -> term val invert_const: string -> string val invert_type_const: string -> string val num_typargs: Context.theory -> string -> int val make_tvar: string -> typ val strip_prefix: string -> string -> string option val setup: Context.theory -> Context.theory (* extracting lemma list*) val find_failure: string -> string option val lemma_list_dfg: string * string vector * Proof.context * Thm.thm * int -> string val lemma_list_tstp: string * string vector * Proof.context * Thm.thm * int -> string (* structured proofs *) val structured_proof: string * string vector * Proof.context * Thm.thm * int -> string end; structure ResReconstruct : RES_RECONSTRUCT = struct val trace_path = Path.basic "atp_trace"; fun trace s = if !Output.debugging then File.append (File.tmp_path trace_path) s else (); val string_of_thm = PrintMode.setmp [] Display.string_of_thm; (*For generating structured proofs: keep every nth proof line*) val (modulus, modulus_setup) = Attrib.config_int "sledgehammer_modulus" 1; (*Indicates whether to include sort information in generated proofs*) val (recon_sorts, recon_sorts_setup) = Attrib.config_bool "sledgehammer_sorts" true; (*Indicated whether to generate full proofs or just lemma lists - now via setup of atps*) (* val (full_proofs, full_proofs_setup) = Attrib.config_bool "sledgehammer_full" false; *) val setup = modulus_setup #> recon_sorts_setup; (**** PARSING OF TSTP FORMAT ****) (*Syntax trees, either termlist or formulae*) datatype stree = Int of int | Br of string * stree list; fun atom x = Br(x,[]); fun scons (x,y) = Br("cons", [x,y]); val listof = List.foldl scons (atom "nil"); (*Strings enclosed in single quotes, e.g. filenames*) val quoted = $$"'" |-- Scan.repeat (~$$"'") --| $$"'" >> implode; (*Intended for $true and $false*) fun tf s = "c_" ^ str (Char.toUpper (String.sub(s,0))) ^ String.extract(s,1,NONE); val truefalse = $$"$" |-- Symbol.scan_id >> (atom o tf); (*Integer constants, typically proof line numbers*) fun is_digit s = Char.isDigit (String.sub(s,0)); val integer = Scan.many1 is_digit >> (valOf o Int.fromString o implode); (*Generalized FO terms, which include filenames, numbers, etc.*) fun termlist x = (term ::: Scan.repeat ($$"," |-- term)) x and term x = (quoted >> atom || integer>>Int || truefalse || Symbol.scan_id -- Scan.optional ($$"(" |-- termlist --| $$")") [] >> Br || $$"(" |-- term --| $$")" || $$"[" |-- Scan.optional termlist [] --| $$"]" >> listof) x; fun negate t = Br("c_Not", [t]); fun equate (t1,t2) = Br("c_equal", [t1,t2]); (*Apply equal or not-equal to a term*) fun syn_equal (t, NONE) = t | syn_equal (t1, SOME (NONE, t2)) = equate (t1,t2) | syn_equal (t1, SOME (SOME _, t2)) = negate (equate (t1,t2)); (*Literals can involve negation, = and !=.*) fun literal x = ($$"~" |-- literal >> negate || (term -- Scan.option (Scan.option ($$"!") --| $$"=" -- term) >> syn_equal)) x; val literals = literal ::: Scan.repeat ($$"|" |-- literal); (*Clause: a list of literals separated by the disjunction sign*) val clause = $$"(" |-- literals --| $$")" || Scan.single literal; val annotations = $$"," |-- term -- Scan.option ($$"," |-- termlist); (*<cnf_annotated> ::= cnf(<name>,<formula_role>,<cnf_formula><annotations>). The <name> could be an identifier, but we assume integers.*) val tstp_line = (Scan.this_string "cnf" -- $$"(") |-- integer --| $$"," -- Symbol.scan_id --| $$"," -- clause -- Scan.option annotations --| $$ ")"; (**** INTERPRETATION OF TSTP SYNTAX TREES ****) exception STREE of stree; (*If string s has the prefix s1, return the result of deleting it.*) fun strip_prefix s1 s = if String.isPrefix s1 s then SOME (ResClause.undo_ascii_of (String.extract (s, size s1, NONE))) else NONE; (*Invert the table of translations between Isabelle and ATPs*) val type_const_trans_table_inv = Symtab.make (map swap (Symtab.dest ResClause.type_const_trans_table)); fun invert_type_const c = case Symtab.lookup type_const_trans_table_inv c of SOME c' => c' | NONE => c; fun make_tvar b = TVar(("'" ^ b, 0), HOLogic.typeS); fun make_var (b,T) = Var((b,0),T); (*Type variables are given the basic sort, HOL.type. Some will later be constrained by information from type literals, or by type inference.*) fun type_of_stree t = case t of Int _ => raise STREE t | Br (a,ts) => let val Ts = map type_of_stree ts in case strip_prefix ResClause.tconst_prefix a of SOME b => Type(invert_type_const b, Ts) | NONE => if not (null ts) then raise STREE t (*only tconsts have type arguments*) else case strip_prefix ResClause.tfree_prefix a of SOME b => TFree("'" ^ b, HOLogic.typeS) | NONE => case strip_prefix ResClause.tvar_prefix a of SOME b => make_tvar b | NONE => make_tvar a (*Variable from the ATP, say X1*) end; (*Invert the table of translations between Isabelle and ATPs*) val const_trans_table_inv = Symtab.update ("fequal", "op =") (Symtab.make (map swap (Symtab.dest ResClause.const_trans_table))); fun invert_const c = case Symtab.lookup const_trans_table_inv c of SOME c' => c' | NONE => c; (*The number of type arguments of a constant, zero if it's monomorphic*) fun num_typargs thy s = length (Sign.const_typargs thy (s, Sign.the_const_type thy s)); (*Generates a constant, given its type arguments*) fun const_of thy (a,Ts) = Const(a, Sign.const_instance thy (a,Ts)); (*First-order translation. No types are known for variables. HOLogic.typeT should allow them to be inferred.*) fun term_of_stree args thy t = case t of Int _ => raise STREE t | Br ("hBOOL",[t]) => term_of_stree [] thy t (*ignore hBOOL*) | Br ("hAPP",[t,u]) => term_of_stree (u::args) thy t | Br (a,ts) => case strip_prefix ResClause.const_prefix a of SOME "equal" => list_comb(Const ("op =", HOLogic.typeT), List.map (term_of_stree [] thy) ts) | SOME b => let val c = invert_const b val nterms = length ts - num_typargs thy c val us = List.map (term_of_stree [] thy) (List.take(ts,nterms) @ args) (*Extra args from hAPP come AFTER any arguments given directly to the constant.*) val Ts = List.map type_of_stree (List.drop(ts,nterms)) in list_comb(const_of thy (c, Ts), us) end | NONE => (*a variable, not a constant*) let val T = HOLogic.typeT val opr = (*a Free variable is typically a Skolem function*) case strip_prefix ResClause.fixed_var_prefix a of SOME b => Free(b,T) | NONE => case strip_prefix ResClause.schematic_var_prefix a of SOME b => make_var (b,T) | NONE => make_var (a,T) (*Variable from the ATP, say X1*) in list_comb (opr, List.map (term_of_stree [] thy) (ts@args)) end; (*Type class literal applied to a type. Returns triple of polarity, class, type.*) fun constraint_of_stree pol (Br("c_Not",[t])) = constraint_of_stree (not pol) t | constraint_of_stree pol t = case t of Int _ => raise STREE t | Br (a,ts) => (case (strip_prefix ResClause.class_prefix a, map type_of_stree ts) of (SOME b, [T]) => (pol, b, T) | _ => raise STREE t); (** Accumulate type constraints in a clause: negative type literals **) fun addix (key,z) = Vartab.map_default (key,[]) (cons z); fun add_constraint ((false, cl, TFree(a,_)), vt) = addix ((a,~1),cl) vt | add_constraint ((false, cl, TVar(ix,_)), vt) = addix (ix,cl) vt | add_constraint (_, vt) = vt; (*False literals (which E includes in its proofs) are deleted*) val nofalses = filter (not o equal HOLogic.false_const); (*Final treatment of the list of "real" literals from a clause.*) fun finish [] = HOLogic.true_const (*No "real" literals means only type information*) | finish lits = case nofalses lits of [] => HOLogic.false_const (*The empty clause, since we started with real literals*) | xs => foldr1 HOLogic.mk_disj (rev xs); (*Accumulate sort constraints in vt, with "real" literals in lits.*) fun lits_of_strees ctxt (vt, lits) [] = (vt, finish lits) | lits_of_strees ctxt (vt, lits) (t::ts) = lits_of_strees ctxt (add_constraint (constraint_of_stree true t, vt), lits) ts handle STREE _ => lits_of_strees ctxt (vt, term_of_stree [] (ProofContext.theory_of ctxt) t :: lits) ts; (*Update TVars/TFrees with detected sort constraints.*) fun fix_sorts vt = let fun tysubst (Type (a, Ts)) = Type (a, map tysubst Ts) | tysubst (TVar (xi, s)) = TVar (xi, getOpt (Vartab.lookup vt xi, s)) | tysubst (TFree (x, s)) = TFree (x, getOpt (Vartab.lookup vt (x,~1), s)) fun tmsubst (Const (a, T)) = Const (a, tysubst T) | tmsubst (Free (a, T)) = Free (a, tysubst T) | tmsubst (Var (xi, T)) = Var (xi, tysubst T) | tmsubst (t as Bound _) = t | tmsubst (Abs (a, T, t)) = Abs (a, tysubst T, tmsubst t) | tmsubst (t $ u) = tmsubst t $ tmsubst u; in fn t => if Vartab.is_empty vt then t else tmsubst t end; (*Interpret a list of syntax trees as a clause, given by "real" literals and sort constraints. vt0 holds the initial sort constraints, from the conjecture clauses.*) fun clause_of_strees ctxt vt0 ts = let val (vt, dt) = lits_of_strees ctxt (vt0,[]) ts in singleton (Syntax.check_terms ctxt) (TypeInfer.constrain HOLogic.boolT (fix_sorts vt dt)) end; fun gen_all_vars t = fold_rev Logic.all (OldTerm.term_vars t) t; fun ints_of_stree_aux (Int n, ns) = n::ns | ints_of_stree_aux (Br(_,ts), ns) = List.foldl ints_of_stree_aux ns ts; fun ints_of_stree t = ints_of_stree_aux (t, []); fun decode_tstp vt0 (name, role, ts, annots) ctxt = let val deps = case annots of NONE => [] | SOME (source,_) => ints_of_stree source val cl = clause_of_strees ctxt vt0 ts in ((name, role, cl, deps), fold Variable.declare_term (OldTerm.term_frees cl) ctxt) end; fun dest_tstp ((((name, role), ts), annots), chs) = case chs of "."::_ => (name, role, ts, annots) | _ => error ("TSTP line not terminated by \".\": " ^ implode chs); (** Global sort constraints on TFrees (from tfree_tcs) are positive unit clauses. **) fun add_tfree_constraint ((true, cl, TFree(a,_)), vt) = addix ((a,~1),cl) vt | add_tfree_constraint (_, vt) = vt; fun tfree_constraints_of_clauses vt [] = vt | tfree_constraints_of_clauses vt ([lit]::tss) = (tfree_constraints_of_clauses (add_tfree_constraint (constraint_of_stree true lit, vt)) tss handle STREE _ => (*not a positive type constraint: ignore*) tfree_constraints_of_clauses vt tss) | tfree_constraints_of_clauses vt (_::tss) = tfree_constraints_of_clauses vt tss; (**** Translation of TSTP files to Isar Proofs ****) fun decode_tstp_list ctxt tuples = let val vt0 = tfree_constraints_of_clauses Vartab.empty (map #3 tuples) in #1 (fold_map (decode_tstp vt0) tuples ctxt) end; (** Finding a matching assumption. The literals may be permuted, and variable names may disagree. We have to try all combinations of literals (quadratic!) and match up the variable names consistently. **) fun strip_alls_aux n (Const("all",_)$Abs(a,T,t)) = strip_alls_aux (n+1) (subst_bound (Var ((a,n), T), t)) | strip_alls_aux _ t = t; val strip_alls = strip_alls_aux 0; exception MATCH_LITERAL; (*Ignore types: they are not to be trusted...*) fun match_literal (t1$u1) (t2$u2) env = match_literal t1 t2 (match_literal u1 u2 env) | match_literal (Abs (_,_,t1)) (Abs (_,_,t2)) env = match_literal t1 t2 env | match_literal (Bound i1) (Bound i2) env = if i1=i2 then env else raise MATCH_LITERAL | match_literal (Const(a1,_)) (Const(a2,_)) env = if a1=a2 then env else raise MATCH_LITERAL | match_literal (Free(a1,_)) (Free(a2,_)) env = if a1=a2 then env else raise MATCH_LITERAL | match_literal (Var(ix1,_)) (Var(ix2,_)) env = insert (op =) (ix1,ix2) env | match_literal _ _ env = raise MATCH_LITERAL; (*Checking that all variable associations are unique. The list env contains no repetitions, but does it contain say (x,y) and (y,y)? *) fun good env = let val (xs,ys) = ListPair.unzip env in not (has_duplicates (op=) xs orelse has_duplicates (op=) ys) end; (*Match one list of literals against another, ignoring types and the order of literals. Sorting is unreliable because we don't have types or variable names.*) fun matches_aux _ [] [] = true | matches_aux env (lit::lits) ts = let fun match1 us [] = false | match1 us (t::ts) = let val env' = match_literal lit t env in (good env' andalso matches_aux env' lits (us@ts)) orelse match1 (t::us) ts end handle MATCH_LITERAL => match1 (t::us) ts in match1 [] ts end; (*Is this length test useful?*) fun matches (lits1,lits2) = length lits1 = length lits2 andalso matches_aux [] (map Envir.eta_contract lits1) (map Envir.eta_contract lits2); fun permuted_clause t = let val lits = HOLogic.disjuncts t fun perm [] = NONE | perm (ctm::ctms) = if matches (lits, HOLogic.disjuncts (HOLogic.dest_Trueprop (strip_alls ctm))) then SOME ctm else perm ctms in perm end; fun have_or_show "show " lname = "show \"" | have_or_show have lname = have ^ lname ^ ": \"" (*ctms is a list of conjecture clauses as yielded by Isabelle. Those returned by the ATP may have their literals reordered.*) fun isar_lines ctxt ctms = let val string_of = PrintMode.setmp [] (fn term => Syntax.string_of_term ctxt term) val _ = trace ("\n\nisar_lines: start\n") fun doline have (lname, t, []) = (*No deps: it's a conjecture clause, with no proof.*) (case permuted_clause t ctms of SOME u => "assume " ^ lname ^ ": \"" ^ string_of u ^ "\"\n" | NONE => "assume? " ^ lname ^ ": \"" ^ string_of t ^ "\"\n") (*no match!!*) | doline have (lname, t, deps) = have_or_show have lname ^ string_of (gen_all_vars (HOLogic.mk_Trueprop t)) ^ "\"\n by (metis " ^ space_implode " " deps ^ ")\n" fun dolines [(lname, t, deps)] = [doline "show " (lname, t, deps)] | dolines ((lname, t, deps)::lines) = doline "have " (lname, t, deps) :: dolines lines in setmp show_sorts (Config.get ctxt recon_sorts) dolines end; fun notequal t (_,t',_) = not (t aconv t'); (*No "real" literals means only type information*) fun eq_types t = t aconv HOLogic.true_const; fun replace_dep (old:int, new) dep = if dep=old then new else [dep]; fun replace_deps (old:int, new) (lno, t, deps) = (lno, t, List.foldl (op union_int) [] (map (replace_dep (old, new)) deps)); (*Discard axioms; consolidate adjacent lines that prove the same clause, since they differ only in type information.*) fun add_prfline ((lno, "axiom", t, []), lines) = (*axioms are not proof lines*) if eq_types t (*must be clsrel/clsarity: type information, so delete refs to it*) then map (replace_deps (lno, [])) lines else (case take_prefix (notequal t) lines of (_,[]) => lines (*no repetition of proof line*) | (pre, (lno',t',deps')::post) => (*repetition: replace later line by earlier one*) pre @ map (replace_deps (lno', [lno])) post) | add_prfline ((lno, role, t, []), lines) = (*no deps: conjecture clause*) (lno, t, []) :: lines | add_prfline ((lno, role, t, deps), lines) = if eq_types t then (lno, t, deps) :: lines (*Type information will be deleted later; skip repetition test.*) else (*FIXME: Doesn't this code risk conflating proofs involving different types??*) case take_prefix (notequal t) lines of (_,[]) => (lno, t, deps) :: lines (*no repetition of proof line*) | (pre, (lno',t',deps')::post) => (lno, t', deps) :: (*repetition: replace later line by earlier one*) (pre @ map (replace_deps (lno', [lno])) post); (*Recursively delete empty lines (type information) from the proof.*) fun add_nonnull_prfline ((lno, t, []), lines) = (*no dependencies, so a conjecture clause*) if eq_types t (*must be type information, tfree_tcs, clsrel, clsarity: delete refs to it*) then delete_dep lno lines else (lno, t, []) :: lines | add_nonnull_prfline ((lno, t, deps), lines) = (lno, t, deps) :: lines and delete_dep lno lines = List.foldr add_nonnull_prfline [] (map (replace_deps (lno, [])) lines); fun bad_free (Free (a,_)) = String.isPrefix "sko_" a | bad_free _ = false; (*TVars are forbidden in goals. Also, we don't want lines with <2 dependencies. To further compress proofs, setting modulus:=n deletes every nth line, and nlines counts the number of proof lines processed so far. Deleted lines are replaced by their own dependencies. Note that the "add_nonnull_prfline" phase may delete some dependencies, hence this phase comes later.*) fun add_wanted_prfline ctxt ((lno, t, []), (nlines, lines)) = (nlines, (lno, t, []) :: lines) (*conjecture clauses must be kept*) | add_wanted_prfline ctxt ((lno, t, deps), (nlines, lines)) = if eq_types t orelse not (null (Term.add_tvars t [])) orelse exists_subterm bad_free t orelse (not (null lines) andalso (*final line can't be deleted for these reasons*) (length deps < 2 orelse nlines mod (Config.get ctxt modulus) <> 0)) then (nlines+1, map (replace_deps (lno, deps)) lines) (*Delete line*) else (nlines+1, (lno, t, deps) :: lines); (*Replace numeric proof lines by strings, either from thm_names or sequential line numbers*) fun stringify_deps thm_names deps_map [] = [] | stringify_deps thm_names deps_map ((lno, t, deps) :: lines) = if lno <= Vector.length thm_names (*axiom*) then (Vector.sub(thm_names,lno-1), t, []) :: stringify_deps thm_names deps_map lines else let val lname = Int.toString (length deps_map) fun fix lno = if lno <= Vector.length thm_names then SOME(Vector.sub(thm_names,lno-1)) else AList.lookup op= deps_map lno; in (lname, t, List.mapPartial fix (distinct (op=) deps)) :: stringify_deps thm_names ((lno,lname)::deps_map) lines end; val proofstart = "proof (neg_clausify)\n"; fun isar_header [] = proofstart | isar_header ts = proofstart ^ "fix " ^ space_implode " " ts ^ "\n"; fun decode_tstp_file cnfs ctxt th sgno thm_names = let val _ = trace "\ndecode_tstp_file: start\n" val tuples = map (dest_tstp o tstp_line o explode) cnfs val _ = trace (Int.toString (length tuples) ^ " tuples extracted\n") val ctxt = ProofContext.set_mode ProofContext.mode_schematic ctxt val raw_lines = List.foldr add_prfline [] (decode_tstp_list ctxt tuples) val _ = trace (Int.toString (length raw_lines) ^ " raw_lines extracted\n") val nonnull_lines = List.foldr add_nonnull_prfline [] raw_lines val _ = trace (Int.toString (length nonnull_lines) ^ " nonnull_lines extracted\n") val (_,lines) = List.foldr (add_wanted_prfline ctxt) (0,[]) nonnull_lines val _ = trace (Int.toString (length lines) ^ " lines extracted\n") val (ccls,fixes) = ResAxioms.neg_conjecture_clauses th sgno val _ = trace (Int.toString (length ccls) ^ " conjecture clauses\n") val ccls = map forall_intr_vars ccls val _ = if !Output.debugging then app (fn th => trace ("\nccl: " ^ string_of_thm th)) ccls else () val ilines = isar_lines ctxt (map prop_of ccls) (stringify_deps thm_names [] lines) val _ = trace "\ndecode_tstp_file: finishing\n" in isar_header (map #1 fixes) ^ String.concat ilines ^ "qed\n" end handle e => (*FIXME: exn handler is too general!*) let val msg = "Translation of TSTP raised an exception: " ^ Toplevel.exn_message e in trace msg; msg end; (* ==== CHECK IF PROOF OF E OR VAMPIRE WAS SUCCESSFUL === *) val failure_strings_E = ["SZS status: Satisfiable","SZS status Satisfiable", "SZS status: ResourceOut","SZS status ResourceOut","# Cannot determine problem status"]; val failure_strings_vampire = ["Satisfiability detected", "Refutation not found", "CANNOT PROVE"]; val failure_strings_SPASS = ["SPASS beiseite: Completion found.", "SPASS beiseite: Ran out of time.", "SPASS beiseite: Maximal number of loops exceeded."]; val failure_strings_remote = ["Remote-script could not extract proof"]; fun find_failure proof = let val failures = map_filter (fn s => if String.isSubstring s proof then SOME s else NONE) (failure_strings_E @ failure_strings_vampire @ failure_strings_SPASS @ failure_strings_remote) in if null failures then NONE else SOME (hd failures) end; (*=== EXTRACTING PROOF-TEXT === *) val begin_proof_strings = ["# SZS output start CNFRefutation.", "=========== Refutation ==========", "Here is a proof"]; val end_proof_strings = ["# SZS output end CNFRefutation", "======= End of refutation =======", "Formulae used in the proof"]; fun get_proof_extract proof = let (*splits to_split by the first possible of a list of splitters*) fun first_field_any [] to_split = NONE | first_field_any (splitter::splitters) to_split = let val result = (first_field splitter to_split) in if isSome result then result else first_field_any splitters to_split end val (a:string, b:string) = valOf (first_field_any begin_proof_strings proof) val (proofextract:string, c:string) = valOf (first_field_any end_proof_strings b) in proofextract end; (* === EXTRACTING LEMMAS === *) (* lines have the form "cnf(108, axiom, ...", the number (108) has to be extracted)*) fun get_step_nums_tstp proofextract = let val toks = String.tokens (not o Char.isAlphaNum) fun inputno ("cnf"::ntok::"axiom"::_) = Int.fromString ntok | inputno _ = NONE val lines = split_lines proofextract in List.mapPartial (inputno o toks) lines end (*String contains multiple lines. We want those of the form "253[0:Inp] et cetera..." A list consisting of the first number in each line is returned. *) fun get_step_nums_dfg proofextract = let val toks = String.tokens (not o Char.isAlphaNum) fun inputno (ntok::"0"::"Inp"::_) = Int.fromString ntok | inputno _ = NONE val lines = split_lines proofextract in List.mapPartial (inputno o toks) lines end (*extracting lemmas from tstp-output between the lines from above*) fun extract_lemmas get_step_nums (proof, thm_names, _, _, _) = let (* get the names of axioms from their numbers*) fun get_axiom_names thm_names step_nums = let fun is_axiom n = n <= Vector.length thm_names fun getname i = Vector.sub(thm_names, i-1) in sort_distinct string_ord (filter (fn x => x <> "??.unknown") (map getname (filter is_axiom step_nums))) end val proofextract = get_proof_extract proof in get_axiom_names thm_names (get_step_nums proofextract) end; (* metis-command *) fun metis_line [] = "apply metis" | metis_line xs = "apply (metis " ^ space_implode " " xs ^ ")" (*Used to label theorems chained into the sledgehammer call*) val chained_hint = "CHAINED"; fun sendback_metis_nochained lemmas = let val nochained = filter_out (fn y => y = chained_hint) in (Markup.markup Markup.sendback o metis_line) (nochained lemmas) end fun lemma_list_tstp result = sendback_metis_nochained (extract_lemmas get_step_nums_tstp result); fun lemma_list_dfg result = sendback_metis_nochained (extract_lemmas get_step_nums_dfg result); (* === Extracting structured Isar-proof === *) fun structured_proof (result as (proof, thm_names, ctxt, goal, subgoalno)) = let (*Could use split_lines, but it can return blank lines...*) val lines = String.tokens (equal #"\n"); val nospaces = String.translate (fn c => if Char.isSpace c then "" else str c) val proofextract = get_proof_extract proof val cnfs = filter (String.isPrefix "cnf(") (map nospaces (lines proofextract)) val one_line_proof = lemma_list_tstp result val structured = if chained_hint mem_string (String.tokens (fn c => c = #" ") one_line_proof) then "" else decode_tstp_file cnfs ctxt goal subgoalno thm_names in one_line_proof ^ "\n\n" ^ (Markup.markup Markup.sendback) structured end end;