(* elements of calculations.

   they are partially held in association lists as ref's for

   switching language levels (meta-string, object-values).                                  

   in order to keep these ref's during re-evaluation of code,                       

   they are defined here at the beginning of the code.

   Author: Walther Neuper 2003

   (c) copyright due to lincense terms

*)

signature CALC_ELEMENT =

  sig

    type eval_fn (*= string -> term -> theory -> (string * term) option*)

    type rew_ord (*= rew_ord' * rew_ord_*)

    eqtype errpatID

    type calc (*= prog_calcID * cal*)

        datatype rule = Cal1 of string * eval_fn | Calc of string * eval_fn | Erule | Rls_ of rls 

      | Thm of string * thm

    and scr

      = EmptyScr

      | Prog of term

      | Rfuns of

          {attach_form: rule list list -> term -> term -> (rule * (term * term list)) list,

           init_state: term -> term * term * rule list list * (rule * (term * term list)) list,

           locate_rule: rule list list -> term -> rule -> (rule * (term * term list)) list,

           next_rule: rule list list -> term -> rule option,

           normal_form: term -> (term * term list) option}

    and rls =

        Erls

      | Rls of {calc: calc list, erls: rls, errpatts: errpatID list, id: string, preconds: term list, 

        rew_ord: rew_ord, rules: rule list, scr: scr, srls: rls}

      | Rrls of {calc: calc list, erls: rls, errpatts: errpatID list, 

        id: string, prepat: (term list * term) list, rew_ord: rew_ord, scr: scr}

      | Seq of {calc: calc list, erls: rls, errpatts: errpatID list, id: string, preconds: term list,

        rew_ord: rew_ord, rules: rule list, scr: scr, srls: rls}

    eqtype rls'

    eqtype theory'

    eqtype prog_calcID

    eqtype calID

    type cas_elem (*= term * (spec * generate_fn)*)

    type pbt (*= {cas: term option, guh: guh, init: pblID, mathauthors: string list, 

      met: metID list, ppc: pat list, prls: rls, thy: theory, where_: term list}*)

    type ptyps (*= pbt ptyp list*)

    type metID (*= string list*)

    type pblID (*= string list*)

    type mets (*= met ptyp list*)

    type met (*= {calc: calc list,

      crls: rls, erls: rls, errpats: errpat list, guh: guh, init: pblID, mathauthors: string list,

      nrls: rls, ppc: pat list, pre: term list, prls: rls, rew_ord': rew_ord', scr: scr, srls: rls}*)

    datatype 'a ptyp = Ptyp of string * 'a list * 'a ptyp list

    type cal = calID * eval_fn

    type authors (*= string list*)

    type guh

    type subst (*= (term * term) list*)

    eqtype thyID

    type fillpat (*= fillpatID * term * errpatID*)

    datatype thydata

      = Hcal of {calc: calc, coursedesign: authors, guh: guh, mathauthors: authors}

      | Hord of {coursedesign: authors, guh: guh, mathauthors: authors, ord: subst -> term * term -> bool}

      | Hrls of {coursedesign: authors, guh: guh, mathauthors: authors, thy_rls: thyID * rls}

      | Hthm of {coursedesign: authors, fillpats: fillpat list, guh: guh, mathauthors: authors, thm: thm}

      | Html of {coursedesign: authors, guh: guh, html: string, mathauthors: authors}

    type theID (*= string list*)

    type rlss_elem (*= rls' * (theory' * rls)*)

    val merge_rlss: rlss_elem list * rlss_elem list -> rlss_elem list

    val rls_eq: (''a * ('b * 'c)) * (''a * ('d * 'e)) -> bool

    type calc_elem (*= prog_calcID * (calID * eval_fn)*)

    val calc_eq: calc_elem * calc_elem -> bool

    type spec (*= domID * pblID * metID*)

    val cas_eq: cas_elem * cas_elem -> bool

    val e_Ptyp: pbt ptyp

    val merge_ptyps: 'a ptyp list * 'a ptyp list -> 'a ptyp list

    val check_guhs_unique: bool Unsynchronized.ref

    val check_pblguh_unique: guh -> pbt ptyp list -> unit

    val insrt: pblID -> 'a -> string list -> 'a ptyp list -> 'a ptyp list

    val e_Mets: met ptyp

    val check_metguh_unique: guh -> met ptyp list -> unit

    val add_thydata: string list * string list -> thydata -> thydata ptyp list -> thydata ptyp list

    val get_py: 'a ptyp list -> pblID -> string list -> 'a

    val update_hthm: thydata -> fillpat list -> thydata

    val update_ptyps: string list -> string list -> 'a -> 'a ptyp list -> 'a ptyp list

    val e_rls: rls

    val e_rrls: rls

    val part2guh: theID -> guh

    val spec2str: string * string list * string list -> string

    val term_to_string''': theory -> term -> string

    val linefeed: string -> string

    val pbts2str: pbt list -> string

    val thes2str: thydata list -> string

    val theID2str: string list -> string

    val the2str: thydata -> string

    val Thy_Info_get_theory: string -> theory

    val string_of_typ: typ -> string

    val string_of_typ_thy: thyID -> typ -> string

    val term2str: term -> string

    val thy2ctxt: theory -> Proof.context

    val trace_calc: bool Unsynchronized.ref

    eqtype thmID

    type thm' (*= thmID * cterm'*)

    datatype lrd = D | L | R

    val trace_rewrite: bool Unsynchronized.ref

    val depth: int Unsynchronized.ref

    val t2str: theory -> term -> string

    val ts2str: theory -> term list -> string

    val terms2str: term list -> string

    val id_rls: rls -> string

    val rls2str: rls -> string

    val rep_rls: rls -> {calc: calc list, erls: rls, id: string, preconds: term list, rew_ord: rew_ord, rules: rule list, scr: scr, srls: rls}

    val string_of_thmI: thm -> string

    val rule2str: rule -> string

    val e_term: term

    val dummy_ord: subst -> term * term -> bool

    val theory2domID: theory -> theory'

    val assoc_thy: theory' -> theory

    val append_rls: string -> rls -> rule list -> rls

    eqtype domID

    val get_rules: rls -> rule list

    val id_rule: rule -> string

    eqtype cterm'

    val term_to_string': Proof.context -> term -> string

    val thy2ctxt': string -> Proof.context

    type rrlsstate = term * term * rule list list * (rule * (term * term list)) list

    type loc_ (*= lrd list*)

    val loc_2str: loc_ -> string

    val e_spec: spec

    val env2str: subst -> string

    val subst2str: subst -> string

    val termopt2str: term option -> string

    eqtype rew_ord'

    type thm'' (*= thmID * thm*)

    type rew_ord_ (*= subst -> term * term -> bool*)

    val metID2str: string list -> string

    val e_domID: domID

    val e_pblID: pblID

    val e_metID: metID

    val empty_spec: spec

    datatype ketype = Exp_ | Met_ | Pbl_ | Thy_

    type kestoreID (*= string list*)

    type errpat (*= errpatID * term list * thm list*)

    val app_py: 'a ptyp list -> ('a ptyp -> 'b) -> pblID -> string list -> 'b

    val ketype2str: ketype -> string

    val coll_pblguhs: pbt ptyp list -> guh list

    val coll_metguhs: met ptyp list -> guh list

    type pat (*= string * (term * term)*)

    val e_type: typ

    val theory2str: theory -> theory'

    val pats2str: pat list -> string

    val string_of_thy: theory -> theory'

    val theory2theory': theory -> theory'

    val maxthy: theory -> theory -> theory

    val e_evalfn: 'a -> term -> theory -> (string * term) option

    val assoc_rew_ord: string -> subst -> term * term -> bool

    eqtype filename

    val rule2str': rule -> string

    val lim_deriv: int Unsynchronized.ref

    val id_of_thm: rule -> string

    val isabthys: unit -> theory list

    val thyID_of_derivation_name: string -> string

    val partID': theory' -> string

    val Isac: 'a -> theory

    val theory'2thyID: theory' -> theory'

    val thm2guh: string * thyID -> thmID -> guh

    val thmID_of_derivation_name: string -> string

    val rls2guh: string * thyID -> rls' -> guh

    val eq_rule: rule * rule -> bool

    val e_rew_ordX: rew_ord

    val theID2guh: theID -> guh

    val thyID2theory': thyID -> thyID

    val e_rule: rule

    val scr2str: scr -> string

    val type2str: typ -> string

    eqtype fillpatID

    type pbt_ = string * (term * term)

    val e_rew_ord: subst -> term * term -> bool

    eqtype xml

    val cal2guh: string * thyID -> string -> guh

    val ketype2str': ketype -> string

    val str2ketype': string -> ketype

    val thmID_of_derivation_name': thm -> string

    val subst2str': subst -> string

    eqtype path

    val theID2thyID: theID -> thyID

    val thy2guh: theID -> guh

    val theory2thyID: theory -> thyID

    val thypart2guh: theID -> guh

    val ord2guh: string * thyID -> rew_ord' -> guh

    val update_hrls: thydata -> errpatID list -> thydata

    eqtype iterID

    eqtype calcID

    val thm''_of_thm: thm -> thm''

    val rew_ord': (rew_ord' * (subst -> term * term -> bool)) list Unsynchronized.ref

    val merge_rls: string -> rls -> rls -> rls

    val e_rrlsstate: rrlsstate

    val thm_of_thm: rule -> thm

    val remove_rls: string -> rls -> rule list -> rls

(*---------------------- ^^^ make public on a minimalist way down to Build?Isac -----------------

    val Html_default: theID -> thydata

    val a_term: term

    val a_type: typ

    val assoc': (string * 'a) list * string -> 'a option

    type generate_fn = term list -> (term * term list) list

    val e_guh: guh

    val e_kestoreID: string list

    val e_met: met

    val e_pbt: pbt

    val e_pbt_: pbt_

    val e_rew_ord': rew_ord'

    val e_rew_ord_: subst -> term * term -> bool

    val e_rfuns: scr

    val e_scr: scr

    val e_subst: (term * term) list

    val e_theID: string list

    val e_thydata: thydata

    val empty_cterm': string

    val eq_thmI: (thmID * thm) * (thmID * 'a) -> bool

    val eq_thmI': (string * 'a) * (string * 'b) -> bool

    val eqrule: rule * rule -> bool

    val fill_parents: string list * string list -> thydata -> thydata ptyp

    val insert_fillpats: thydata ptyp list -> (pblID * fillpat list) list -> thydata ptyp list -> thydata ptyp list

    val insert_merge_rls: rlss_elem -> rlss_elem list -> rlss_elem list

    val insthy: 'a -> 'b * 'c -> 'b * ('a * 'c)

    val kestoreID2str: string list -> string

    val knowthys: unit -> theory list

    val ldr2str: lrd -> string

    val lim_rewrite: int Unsynchronized.ref

    val memrls: rule -> rls -> bool

    val merge_ids: rls -> rls -> string

    val merge_ptyps': 'a ptyp list -> 'a ptyp list -> 'a ptyp list

    val overwritelthy: theory -> (rls' * (string * rls)) list * (rls' * rls) list -> (rls' * (string * rls)) list

    val partID: theory -> string

    val pat2str: pat -> string

    val pblID2str: string list -> string

    val pbt2str: pbt -> string

    val progthys: unit -> theory list

    val rep_rrls:

       rls -> {attach_form: rule list list -> term -> term -> (rule * (term * term list)) list,

               calc: calc list,

               erls: rls,

               errpatts: errpatID list,

               id: string,

               init_state: term -> term * term * rule list list * (rule * (term * term list)) list,

               locate_rule: rule list list -> term -> rule -> (rule * (term * term list)) list,

               next_rule: rule list list -> term -> rule option, normal_form: term -> (term * term list) option, prepat: (term list * term) list, rew_ord: rew_ord}

    val rep_thm_G': rule -> string * thm

    val str2ketype: string -> ketype

    val string_of_thm: thm -> string

    val string_of_thm': theory -> thm -> string

    val string_to_bool: string -> bool

    type subs' = (cterm' * cterm') list

    val term_to_string'': thyID -> term -> string

    val terms2str': term list -> string

    val terms2strs: term list -> string list

    type thehier = thydata ptyp list

    val theory2str': theory -> string

    val thm2str: thm -> string

    eqtype thmDeriv

    val thy2ctxt: theory -> Proof.context

    val type_to_string': Proof.context -> typ -> string

    val type_to_string'': thyID -> typ -> string

    val type_to_string''': theory -> typ -> string

  ----------------------------------------- ^^^ make public -----------------------------------*)

(* ---- for tests only: shifted from below to remove the Warning "unused" at fun.def. --------- *)

    (* NONE *)

(*/-------------------------------------------------------- ! aktivate for Test_Isac BEGIN ---\* )

    (* NONE *)

( *\--- ! aktivate for Test_Isac END ----------------------------------------------------------/*)

  end

(**)

structure Celem(**): CALC_ELEMENT(**) =

struct

(**)

val linefeed = (curry op^) "\n";

type authors = string list;

type cterm' = string;

val empty_cterm' = "empty_cterm'";

(* TODO CLEANUP Thm:

type rule = 

Thm (string, thm): (a) needs string to identify sym_thmID for handling in front-end;

                   (b) investigate if ""RS sym" attaches a [.]" still occurs: string_of_thmI

thmID            : type for data from user input + program

thmDeriv         : type for thy_hierarchy ONLY

obsolete types   : thm' (SEE "ad thm'"), thm''. 

revise funs      : id_of_thm, thm_of_thm, rep_thm_G', eq_thmI, eq_thmI', thm''_of_thm thm.

activate         : thmID_of_derivation_name'

*)

type iterID = int;

type calcID = int;

type thmID = string;    (* identifier for a thm (the shortest possible identifier)       *)

type thmDeriv = string; (* WN120524 deprecated

  thyID ^"."^ xxx ^"."^ thmID, see fun thmID_of_derivation_name 

  WN120524: dont use Thm.derivation_name, this is destroyed by num_str;

  Thm.get_name_hint survives num_str and seems perfectly reliable *)

type thm' = thmID * cterm';(*WN060610 deprecated in favour of thm''*)

(* tricky combination of (string, term) for theorems in Isac:

  * case 1 general: frontend + lucin, e.g. applicable_in..Rewrite: (thmID, _) --> (thmID, thm)

    by Global_Theory.get_thm, special cases ("add_commute",..) see convert_metaview_to_thmid.

  * case 2 "sym_..": Global_Theory.get_thm..RS sym

  * case 3 ad-hoc thm "#..." mk_thm from ad-hoc term (numerals only) in calculate_:

    from applicable_in..Calculate: opstr --calculate_/adhoc_thm--> (thmID, thm)

*)

type thm'' = thmID * thm; (* only for transport via libisabelle isac-java <--- ME *)

type rls' = string;

(*.a 'guh'='globally unique handle' is a string unique for each element

   of isac's KEStore and persistent over time

   (in particular under shifts within the respective hierarchy);

   specialty for thys:

   # guh NOT resistant agains shifts from one thy to another

   (which is the price for Isabelle's design: thy's overwrite ids of subthy's)

   # requirement for matchTheory: induce guh from tac + current thy

   (see 'fun thy_containing_thm', 'fun thy_containing_rls' etc.)

   TODO: introduce to pbl, met.*)

type guh = string;

val e_guh = "e_guh":guh;

type xml = string; (* rm together with old code replaced by XML.tree *)

fun string_to_bool "true" = true

  | string_to_bool "false" = false

  | string_to_bool str = error ("string_to_bool: arg = " ^ str)

(* eval function calling sml code during rewriting.

Unifying "type cal" and "type calc" would make Lucas-Interpretation more efficient,

  see "fun rule2stac": instead of 

    Calc: calID * eval_fn -> rule

  would be better

    Calc: prog_calcID * (calID * eval_fn)) -> rule*)

type eval_fn = (string -> term -> theory -> (string * term) option);

fun e_evalfn (_:'a) (_:term) (_:theory) = NONE:(string * term) option;

(*. op in isa-term 'Const(op,_)' .*)

type calID = string;

(* *)

type cal = (calID * eval_fn);

(*. fun calculate_ fetches the evaluation-function via this list. *)

type prog_calcID = string;

type calc = (prog_calcID * cal);

type calc_elem =

  prog_calcID *   (* a simple identifier used in programs *)

  (calID *        (* a long identifier used in Const *)

    eval_fn)      (* an ML function *)

fun calc_eq ((pi1, (ci1, _)) : calc_elem, (pi2, (ci2, _)) : calc_elem) =

  if pi1 = pi2

  then if ci1 = ci2 then true else error ("calc_eq: " ^ ci1 ^ " <> " ^ ci2)

  else false

type subs' = (cterm' * cterm') list; (*16.11.00 for FE-KE*)

type subst = (term * term) list; (*here for ets2str*)

val e_subst = []:(term * term) list;

(*TODO.WN060610 make use of "type rew_ord" total*)

type rew_ord' = string;

val e_rew_ord' = "e_rew_ord" : rew_ord';

type rew_ord_ = subst -> Term.term * Term.term -> bool;

fun dummy_ord (_:subst) (_:term,_:term) = true;

val e_rew_ord_ = dummy_ord;

type rew_ord = rew_ord' * rew_ord_;

val e_rew_ord = dummy_ord; (* TODO.WN071231 clarify identifiers..e_rew_ordX*)

val e_rew_ordX = (e_rew_ord', e_rew_ord_) : rew_ord;

(* error patterns and fill patterns *)

type errpatID = string

type errpat =

  errpatID    (* one identifier for a list of patterns                       

                 DESIGN ?TODO: errpatID list for hierarchy of errpats ?      *)

  * term list (* error patterns                                              *)

  * thm list  (* thms related to error patterns; note that respective lhs 

                 do not match (which reflects student's error).

                 fillpatterns are stored with these thms.                    *)

(* for (at least) 2 kinds of access:

  (1) given an errpatID, find the respective fillpats (e.g. in fun find_fill_pats)

  (2) given a thm, find respective fillpats *)

type fillpatID = string

type fillpat =

  fillpatID   (* DESIGN ?TODO: give an order w.r.t difficulty ? *)

  * term      (* the pattern with fill-in gaps                  *)

  * errpatID; (* which the fillpat would be a help for          

                 DESIGN ?TODO: list for several patterns ?      *)

datatype rule =

  Erule                (*.the empty rule                     .*)

| Thm of (string * Basic_Thm.thm) (* see TODO CLEANUP Thm     *)

| Calc of string *     (*.sml-code manipulating a (sub)term  .*)

	  eval_fn

| Cal1 of string *     (*.sml-code applied only to whole term

                          or left/right-hand-side of eqality .*)

	  eval_fn

| Rls_ of rls          (*.ie. rule sets may be nested.*)

and scr =

    EmptyScr

  | Prog of term (* a leaf is either a tactic or an 'exp' in 'let v = expr' 

                    where 'exp' does not contain a tactic. *)

  | Rfuns of     (* for Rrls, usage see rational.sml ----- reverse rewrite -----      *)

    {init_state : (* initialise for reverse rewriting by the Interpreter              *)

      term ->         (* for this the rrlsstate is initialised:                       *)

      term *          (* the current formula: goes locate_gen -> next_tac via istate  *)

      term *          (* the final formula                                            *)

      rule list       (* of reverse rewrite set (#1#)                                 *)

        list *        (*   may be serveral, eg. in norm_rational                      *)

      ( rule *        (* Thm (+ Thm generated from Calc) resulting in ...             *)

        (term *       (*   ... rewrite with ...                                       *)

        term list))   (*   ... assumptions                                            *)

      list,           (* derivation from given term to normalform

                         in reverse order with sym_thm;

                                                (#1#) could be extracted from here #1 *)  

	  normal_form:  (* the function which drives the Rrls ##############################*)

	    term -> (term * term list) option,

	  locate_rule:  (* checks a rule R for being a cancel-rule, and if it is,

                     then return the list of rules (+ the terms they are rewriting to)

                     which need to be applied before R should be applied.

                     precondition: the rule is applicable to the argument-term.       *)

	    rule list list -> (* the reverse rule list                                      *)

	    term ->         (* ... to which the rule shall be applied                       *)

	    rule ->         (* ... to be applied to term                                    *)

	    ( rule *        (* value: a rule rewriting to ...                               *)

	      (term *       (*   ... the resulting term ...                                 *)

	      term list))   (*   ... with the assumptions ( //#0)                           *)

	    list,           (*   there may be several such rules; the list is empty,          

                           if the rule has nothing to do with e.g. cancelation        *)

	  next_rule:    (* for a given term return the next rules to be done for cancelling *)

	    rule list list->(* the reverse rule list                                        *)

	    term ->         (* the term for which ...                                       *)

	    rule option,    (* ... this rule is appropriate for cancellation;

		                     there may be no such rule (if the term is eg.canceled already*)

	  attach_form:  (* checks an input term TI, if it may belong to e.g. a current 

                     cancellation, by trying to derive it from the given term TG.     

                     NOT IMPLEMENTED                                                 *)

	    rule list list->(**)

	    term ->         (* TG, the last one agreed upon by user + math-eng              *)

	    term ->         (* TI, the next one input by the user                           *)

	    ( rule *        (* the rule to be applied in order to reach TI                  *) 

	      (term *       (* ... obtained by applying the rule ...                        *)

	      term list))   (* ... and the respective assumptions                           *) 

	    list}           (* there may be several such rules; the list is empty, if the 

                         users term does not belong to e.g. a cancellation of the term 

                         last agreed upon.                                            *)

and rls =

    Erls                          (*for init e_rls*)

  | Rls of (*a confluent and terminating ruleset, in general         *)

    {id : string,          (*for trace_rewrite:=true                 *)

     preconds : term list, (*unused WN020820                         *)

     (*WN060616 for efficiency...

      bdvs    : false,       (*set in prep_rls' for get_bdvs *)*)

     rew_ord  : rew_ord,   (*for rules*)

     erls     : rls,       (*for the conditions in rules             *)

     srls     : rls,       (*for evaluation of list_fns in script    *)

     calc     : calc list, (*for Calculate in scr, set by prep_rls'   *)

     rules    : rule list,

     errpatts : errpatID list,(*dialog-authoring in Build_Thydata.thy*)

     scr      : scr}       (*Prog term: generating intermed.steps  *)

  | Seq of (*a sequence of rules to be tried only once               *)

    {id : string,          (*for trace_rewrite:=true                 *)

     preconds : term list, (*unused 20.8.02                          *)

     (*WN060616 for efficiency...

      bdvs    : false,       (*set in prep_rls' for get_bdvs *)*)

     rew_ord  : rew_ord,   (*for rules                               *)

     erls     : rls,       (*for the conditions in rules             *)

     srls     : rls,       (*for evaluation of list_fns in script    *)

     calc     : calc list, (*for Calculate in scr, set by prep_rls'   *)

     rules    : rule list,

     errpatts : errpatID list,(*dialog-authoring in Build_Thydata.thy*)

     scr      : scr}  (*Prog term  (how to restrict type ???)*)

  (*Rrls call SML-code and simulate an rls

    difference: there is always _ONE_ redex rewritten in 1 call,

    thus wrap Rrls by: Rls (Rls_ ...)*)

  | Rrls of (* SML-functions within rewriting; step-wise execution provided;   

               Rrls simulate an rls

               difference: there is always _ONE_ redex rewritten in 1 call,

               thus wrap Rrls by: Rls (Rls_ ...)                              *)

    {id : string,          (* for trace_rewrite := true                       *)

     prepat  : (term list *(* preconds, eval with subst from pattern;

                              if [@{term True}], match decides alone          *)

		            term )     (* pattern matched with current (sub)term          *)

		   list,               (* meta-conjunction is or                          *)

     rew_ord  : rew_ord,   (* for rules                                       *)

     erls     : rls,       (* for the conditions in rules and preconds        *)

     calc     : calc list, (* for Calculate in scr, set automatic.in prep_rls' *)

     errpatts : errpatID list,(*dialog-authoring in Build_Thydata.thy*)

     scr      : scr};      (* Rfuns {...}  (how to restrict type ???)         *)

(*ad thm':

   there are two kinds of theorems ...

   (1) known by isabelle

   (2) not known, eg. calc_thm, instantiated rls

       the latter have a thmid "#..."

   and thus outside isa we ALWAYS transport both (thmID, string_of_thmI)

   and have a special assoc_thm / assoc_rls in this interface      *)

type theory' = string; (* = domID ^".thy" WN.101011 ABOLISH !*)

type domID = string;   (* domID ^".thy" = theory' WN.101011 replace by thyID*)

type thyID = string;    (*WN.3.11.03 TODO: replace domID with thyID*)

(* Since Isabelle2017 sessions in theory identifiers are enforced.

  However, we leave theory identifiers short, in particular in use as keys into KEStore. *)

fun Thy_Info_get_theory thyID = Thy_Info.get_theory ("Isac." ^ thyID)

fun thm2str thm =

  let

    val t = Thm.prop_of thm

    val ctxt = Proof_Context.init_global (Thy_Info.get_theory ("Isac.Isac"))

    val ctxt' = Config.put show_markup false ctxt

  in Print_Mode.setmp [] (Syntax.string_of_term ctxt') t end;

fun term_to_string' ctxt t =

  let

    val ctxt' = Config.put show_markup false ctxt

  in Print_Mode.setmp [] (Syntax.string_of_term ctxt') t end;

fun term_to_string'' (thyID : thyID) t =

  let

    val ctxt' = Config.put show_markup false (Proof_Context.init_global (Thy_Info_get_theory thyID))

  in Print_Mode.setmp [] (Syntax.string_of_term ctxt') t end;

fun term_to_string''' thy t =

  let

    val ctxt' = Config.put show_markup false (Proof_Context.init_global thy)

  in Print_Mode.setmp [] (Syntax.string_of_term ctxt') t end;

fun thy2ctxt' thy' = Proof_Context.init_global (Thy_Info_get_theory thy');(*FIXXXME thy-ctxt*)

fun thy2ctxt thy = Proof_Context.init_global thy;(*FIXXXME thy-ctxt*)

fun term2str t = term_to_string' (thy2ctxt' "Isac") t;

fun t2str thy t = term_to_string' (thy2ctxt thy) t;

fun ts2str thy ts = ts |> map (t2str thy) |> strs2str';

fun terms2strs ts = map term2str ts;

(*terms2strs [t1,t2] = ["1 + 2", "abc"];*)

val terms2str = strs2str o terms2strs;

(*terms2str [t1,t2] = "[\"1 + 2\",\"abc\"]";*)

val terms2str' = strs2str' o terms2strs;

(*terms2str' [t1,t2] = "[1 + 2,abc]";*)

fun termopt2str (SOME t) = "(SOME " ^ term2str t ^ ")"

  | termopt2str NONE = "NONE";

fun type_to_string' ctxt t =

  let

    val ctxt' = Config.put show_markup false ctxt

  in Print_Mode.setmp [] (Syntax.string_of_typ ctxt') t end;

fun type_to_string'' (thyID : thyID) t =

  let

    val ctxt' = Config.put show_markup false (Proof_Context.init_global (Thy_Info_get_theory thyID))

  in Print_Mode.setmp [] (Syntax.string_of_typ ctxt') t end;

fun type_to_string''' thy t =

  let

    val ctxt' = Config.put show_markup false (Proof_Context.init_global thy)

  in Print_Mode.setmp [] (Syntax.string_of_typ ctxt') t end;

fun type2str typ = type_to_string'' "Isac" typ; (*legacy*)

val string_of_typ = type2str; (*legacy*)

fun string_of_typ_thy thy typ = type_to_string'' thy typ; (*legacy*)

fun Isac _ = Proof_Context.theory_of (thy2ctxt' "Isac"); (*@{theory "Isac"}*)

val e_rule = Thm ("refl", @{thm refl});

fun id_of_thm (Thm (id, _)) = id  (* TODO re-arrange code for rule2str *)

  | id_of_thm _ = raise ERROR ("id_of_thm: uncovered case " (* ^ rule2str r *))

fun thm_of_thm (Thm (_, thm)) = thm  (* TODO re-arrange code for rule2str *)

  | thm_of_thm _ = raise ERROR ("thm_of_thm: uncovered case " (* ^ rule2str r *))

fun rep_thm_G' (Thm (thmid, thm)) = (thmid, thm)  (* TODO re-arrange code for rule2str *)

  | rep_thm_G' _ = raise ERROR ("rep_thm_G': uncovered case " (* ^ rule2str r *))

fun thmID_of_derivation_name dn = last_elem (space_explode "." dn);

fun thmID_of_derivation_name' thm = (thmID_of_derivation_name o Thm.get_name_hint) thm

fun thyID_of_derivation_name dn = hd (space_explode "." dn);

fun thm''_of_thm thm = (thmID_of_derivation_name' thm, thm) : thm''

fun eq_thmI ((thmid1 : thmID, _ : thm), (thmid2 : thmID, _ : thm)) =

    (strip_thy thmid1) = (strip_thy thmid2);

(*WN120201 weakened*)

fun eq_thmI ((thmid1 : thmID, _ : thm), (thmid2 : thmID, _)) = thmid1 = thmid2;

(*version typed weaker WN100910*)

fun eq_thmI' ((thmid1, _), (thmid2, _)) =

    (thmID_of_derivation_name thmid1) = (thmID_of_derivation_name thmid2);

(*check for [.] as caused by "fun assoc_thm'"*)

fun string_of_thm thm = term_to_string' (thy2ctxt' "Isac") (Thm.prop_of thm)

fun string_of_thm' thy thm = term_to_string' (thy2ctxt thy) (Thm.prop_of thm)

fun string_of_thmI thm =

  let 

    val str = (de_quote o string_of_thm) thm

    val (a, b) = split_nlast (5, Symbol.explode str)

  in 

    case b of

      [" ", " ","[", ".", "]"] => implode a

    | _ => str

  end

(*.id requested for all, Rls,Seq,Rrls.*)

fun id_rls Erls = "e_rls" (*WN060714 quick and dirty: recursive defs!*)

  | id_rls (Rls {id,...}) = id

  | id_rls (Seq {id,...}) = id

  | id_rls (Rrls {id,...}) = id;

val rls2str = id_rls;

fun id_rule (Thm (id, _)) = id

  | id_rule (Calc (id, _)) = id

  | id_rule (Rls_ rls) = id_rls rls;

fun get_rules (Rls {rules,...}) = rules

  | get_rules (Seq {rules,...}) = rules

  | get_rules (Rrls _) = [];

fun rule2str Erule = "Erule"

  | rule2str (Thm (str, thm)) = "Thm (\""^str^"\","^(string_of_thmI thm)^")"

  | rule2str (Calc (str,f))  = "Calc (\""^str^"\",fn)"

  | rule2str (Cal1 (str,f))  = "Cal1 (\""^str^"\",fn)"

  | rule2str (Rls_ rls) = "Rls_ (\""^id_rls rls^"\")";

fun rule2str' Erule = "Erule"

  | rule2str' (Thm (str, thm)) = "Thm (\""^str^"\",\"\")"

  | rule2str' (Calc (str,f))  = "Calc (\""^str^"\",fn)"

  | rule2str' (Cal1 (str,f))  = "Cal1 (\""^str^"\",fn)"

  | rule2str' (Rls_ rls) = "Rls_ (\""^id_rls rls^"\")";

(*WN080102 compare eq_rule ?!?*)

fun eqrule (Thm (id1,_), Thm (id2,_)) = id1 = id2

  | eqrule (Calc (id1,_), Calc (id2,_)) = id1 = id2

  | eqrule (Cal1 (id1,_), Cal1 (id2,_)) = id1 = id2

  | eqrule (Rls_ _, Rls_ _) = false (*{id=id1}{id=id2} = id1 = id2 FIXXME*)

  | eqrule _ = false;

type rrlsstate =  (* state for reverse rewriting, comments see type rule and scr | Rfuns *)

  (term * term * rule list list * (rule * (term * term list)) list);

val e_type = Type("empty",[]);

val a_type = TFree("'a",[]);

val e_term = Const("empty",e_type);

val a_term = Free("empty",a_type);

val e_rrlsstate = (e_term,e_term,[[e_rule]],[(e_rule,(e_term,[]))]):rrlsstate;

val e_term = Const("empty", Type("'a", []));

val e_scr = Prog e_term;

fun string_of_thy thy = Context.theory_name thy: theory';

val theory2domID = string_of_thy;

val theory2thyID = (get_thy o string_of_thy) : theory -> thyID;

val theory2theory' = string_of_thy;

val theory2str = string_of_thy; (*WN050903 ..most consistent naming*)

val theory2str' = implode o (drop_last_n 4) o Symbol.explode o string_of_thy;

(* fun theory'2theory = fun thyID2thy ... see fun assoc_thy (...Thy_Info_get_theory string);

al it = "Isac" : string

*)

fun thyID2theory' (thyID:thyID) = thyID;

(*

    let val ss = Symbol.explode thyID

	val ext = implode (takelast (4, ss))

    in if ext = ".thy" then thyID : theory' (*disarm abuse of thyID*)

       else thyID ^ ".thy"

    end;

*)

(* thyID2theory' "Isac" (*ok*);

val it = "Isac" : theory'

 > thyID2theory' "Isac" (*abuse, goes ok...*);

val it = "Isac" : theory'

*)

fun theory'2thyID (theory':theory') = theory';

(*

    let val ss = Symbol.explode theory'

	val ext = implode (takelast (4, ss))

    in if ext = ".thy" then ((implode o (drop_last_n 4)) ss) : thyID

       else theory' (*disarm abuse of theory'*)

    end;

*)

(* theory'2thyID "Isac";

val it = "Isac" : thyID

> theory'2thyID "Isac";

val it = "Isac" : thyID*)

(*. WN0509 discussion:

#############################################################################

#   How to manage theorys in subproblems wrt. the requirement,              #

#   that scripts should be re-usable ?                                      #

#############################################################################

    eg. 'Script Solve_rat_equation' calls 'SubProblem (RatEq',..'

    which would not allow to 'solve (y'' = -M_b / EI, M_b)' by this script

    because Biegelinie.thy is subthy of RatEq.thy and thus Biegelinie.M_b

    is unknown in RatEq.thy and M_b cannot be parsed into the scripts guard

    (see match_ags).

    Preliminary solution:

    # the thy in 'SubProblem (thy', pbl, arglist)' is not taken automatically,

    # instead the 'maxthy (rootthy pt) thy' is taken for each subpbl

    # however, a thy specified by the user in the rootpbl may lead to

      errors in far-off subpbls (which are not yet reported properly !!!)

      and interactively specifiying thys in subpbl is not very relevant.

    Other solutions possible:

    # always parse and type-check with Thy_Info_get_theory "Isac"

      (rejected tue to the vague idea eg. to re-use equations for R in C etc.)

    # regard the subthy-relation in specifying thys of subpbls

    # specifically handle 'SubProblem (undefined, pbl, arglist)'

    # ???

.*)

(*WN0509 TODO "ProtoPure" ... would be more consistent

  with assoc_thy <--> theory2theory' +FIXME assoc_thy "e_domID" -> Script.thy*)

val e_domID = "e_domID":domID;

(*the key into the hierarchy ob theory elements*)

type theID = string list;

val e_theID = ["e_theID"];

val theID2str = strs2str;

(*theID eg. is ["IsacKnowledge", "Test", "Rulesets", "ac_plus_times"]*)

fun theID2thyID (theID:theID) =

    if length theID >= 3 then (last_elem o (drop_last_n 2)) theID : thyID

    else error ("theID2thyID called with "^ theID2str theID);

(*the key into the hierarchy ob problems*)

type pblID = string list; (* domID::...*)

val e_pblID = ["e_pblID"]:pblID;

val pblID2str = strs2str;

(*the key into the hierarchy ob methods*)

type metID = string list;

val e_metID = ["e_metID"]:metID;

val metID2str = strs2str;

type spec = 

     domID * (*WN.12.03: is replaced by thy from get_met ?FIXME? in:

	      specify (Init_Proof..), nxt_specify_init_calc,

	      assod (.SubProblem...), stac2tac (.SubProblem...)*)

     pblID * 

     metID;

fun spec2str ((dom,pbl,met)(*:spec*)) = 

  "(" ^ (quote dom) ^ ", " ^ (strs2str pbl) ^ 

  ", " ^ (strs2str met) ^ ")";

(*> spec2str empty_spec;

val it = "(\"\", [], (\"\", \"\"))" : string *)

val empty_spec = (e_domID,e_pblID,e_metID):spec;

val e_spec = empty_spec;

(*.association list with cas-commands, for generating a complete calc-head.*)

type generate_fn = 

  (term list ->    (* the arguments of the cas-command, eg. (x+1=2, x) *)

    (term *        (* description of an element                        *)

      term list)   (* value of the element (always put into a list)    *)

  list)            (* of elements in the formalization                 *)

type cas_elem = 

  (term *          (* cas-command, eg. 'solve'                         *)

    (spec *        (* theory, problem, method                          *)

    generate_fn))

fun cas_eq ((t1, (_, _)) : cas_elem, (t2, (_, _)) : cas_elem) = t1 = t2

(*either theID or pblID or metID*)

type kestoreID = string list;

val e_kestoreID = ["e_kestoreID"];

val kestoreID2str = strs2str;

(*for distinction of contexts WN130621: disambiguate with Isabelle's Context !*)

datatype ketype = Exp_ | Thy_ | Pbl_ | Met_;

fun ketype2str Exp_ = "Exp_"

  | ketype2str Thy_ = "Thy_"

  | ketype2str Pbl_ = "Pbl_"

  | ketype2str Met_ = "Met_";

fun ketype2str' Exp_ = "Example"

  | ketype2str' Thy_ = "Theory"

  | ketype2str' Pbl_ = "Problem"

  | ketype2str' Met_ = "Method";

fun str2ketype "Exp_" = Exp_

  | str2ketype "Thy_" = Thy_

  | str2ketype "Pbl_" = Pbl_

  | str2ketype "Met_" = Met_

  | str2ketype str = raise ERROR ("str2ketype: WRONG arg = " ^ str)

(* for conversion from XML *)

fun str2ketype' "exp" = Exp_

  | str2ketype' "thy" = Thy_

  | str2ketype' "pbl" = Pbl_

  | str2ketype' "met" = Met_

  | str2ketype' str = raise ERROR ("str2ketype': WRONG arg = " ^ str)

(*rewrite orders, also stored in 'type met' and type 'and rls'

  The association list is required for 'rewrite.."rew_ord"..'

  WN0509 tests not well-organized: see smltest/Knowledge/termorder.sml*)

val rew_ord' = Unsynchronized.ref

        ([]:(rew_ord' *        (*the key for the association list         *)

	     (subst 	       (*the bound variables - they get high order*)

	      -> (term * term) (*(t1, t2) to be compared                  *)

	      -> bool))        (*if t1 <= t2 then true else false         *)

		list);         (*association list                         *)

(* NOT ACCEPTED BY struct

rew_ord' := overwritel (!rew_ord', [("e_rew_ord", e_rew_ord),

				    ("dummy_ord", dummy_ord)]);

*)

(* A tree for storing data defined in different theories 

  for access from the Interpreter and from dialogue authoring 

  using a string list as key.

  'a is for pbt | met | thydata; after WN030424 naming became inappropriate *)

datatype 'a ptyp =

	Ptyp of string * (* element of the key *)

		'a list *      (* several pbts with different domIDs/thy TODO: select by subthy (isaref.p.69)

			                presently only _ONE_ elem FOR ALL KINDS OF CONTENT pbt | met | thydata *)

		('a ptyp) list;(* the children nodes *)

(*.datatype for collecting thydata for hierarchy.*)

(*WN060720 more consistent naming would be 'type thyelem' or 'thelem'*)

(*WN0606 Htxt contains html which does not belong to the sml-kernel*)

datatype thydata = Html of {guh: guh,

			    coursedesign: authors,

			    mathauthors: authors,

			    html: string} (*html; for demos before database*)

		 | Hthm of {guh: guh,

			    coursedesign: authors,

			    mathauthors: authors,

			    fillpats: fillpat list,

			    thm: thm} (* here no sym_thm, thus no thmID required *)

		 | Hrls of {guh: guh,

			    coursedesign: authors,

			    mathauthors: authors,

			    thy_rls: (thyID * rls)}

		 | Hcal of {guh: guh,

			    coursedesign: authors,

			    mathauthors: authors,

			    calc: calc}

		 | Hord of {guh: guh,

			    coursedesign: authors,

			    mathauthors: authors,

			    ord: (subst -> (term * term) -> bool)};

val e_thydata = Html {guh="e_guh", coursedesign=[], mathauthors=[], html=""};

fun the2str (Html {guh, coursedesign, mathauthors, html}) = guh : string

  | the2str (Hthm {guh, coursedesign, mathauthors, fillpats, thm}) = guh

  | the2str (Hrls {guh, coursedesign, mathauthors, thy_rls}) = guh

  | the2str (Hcal {guh, coursedesign, mathauthors, calc}) = guh

  | the2str (Hord {guh, coursedesign, mathauthors, ord}) = guh

fun thes2str thes = map the2str thes |> list2str;

(* notes on thehier concerning sym_thmID theorems (created in derivations, reverse rewriting)

     (a): thehier does not contain sym_thmID theorems

     (b): lookup for sym_thmID directly from Isabelle using sym_thm

          (within math-engine NO lookup in thehier -- within java in *.xml only!)

TODO (c): export from thehier to xml

TODO (c1)   creates one entry for "thmID" (and NONE for "sym_thmID") in the hierarchy

TODO (c2)   creates 2 files "thy_*-thm-thmID.xml" and "thy_*-thm-sym_thmID.xml"

TODO (d): 1 entry in the MiniBrowser's hierarchy (generated from xml)

          stands for both, "thmID" and "sym_thmID" 

TODO (d1)   lookup from calctxt          

TODO (d1)   lookup from from rule set in MiniBrowser *)

type thehier = (thydata ptyp) list;

(* required to determine sequence of main nodes of thehier in KEStore.thy *)

fun part2guh ([str]:theID) =

    (case str of

	"Isabelle" => "thy_isab_" ^ str ^ "-part" : guh

      | "IsacScripts" => "thy_scri_" ^ str ^ "-part"

      | "IsacKnowledge" => "thy_isac_" ^ str ^ "-part"

      | str => error ("thy2guh: called with '"^str^"'"))

  | part2guh theID = error ("part2guh called with theID = " ^ theID2str theID);

fun thy2guh ([part, thyID] : theID) = (case part of

      "Isabelle" => "thy_isab_" ^ thyID : guh

    | "IsacScripts" => "thy_scri_" ^ thyID

    | "IsacKnowledge" => "thy_isac_" ^ thyID

    | str => error ("thy2guh: called with '" ^ str ^ "'"))

  | thy2guh theID = error ("thy2guh called with '" ^ strs2str' theID ^ "'");

fun thypart2guh ([part, thyID, thypart] : theID) = case part of

    "Isabelle" => "thy_isab_" ^ thyID ^ "-" ^ thypart : guh

  | "IsacScripts" => "thy_scri_" ^ thyID ^ "-" ^ thypart

  | "IsacKnowledge" => "thy_isac_" ^ thyID ^ "-" ^ thypart

  | str => error ("thypart2guh: called with '" ^ str ^ "'");

(* convert the data got via contextToThy to a globally unique handle

   there is another way to get the guh out of the 'theID' in the hierarchy *)

fun thm2guh (isa, thyID:thyID) (thmID:thmID) = case isa of

    "Isabelle" => "thy_isab_" ^ theory'2thyID thyID ^ "-thm-" ^ strip_thy thmID : guh

  | "IsacKnowledge" => "thy_isac_" ^ theory'2thyID thyID ^ "-thm-" ^ strip_thy thmID

  | "IsacScripts" => "thy_scri_" ^ theory'2thyID thyID ^ "-thm-" ^ strip_thy thmID

  | str => error ("thm2guh called with isa = '" ^ isa ^ "' for thm = " ^ thmID ^ "'");

fun rls2guh (isa, thyID:thyID) (rls':rls') = case isa of

    "Isabelle" => "thy_isab_" ^ theory'2thyID thyID ^ "-rls-" ^ rls' : guh

  | "IsacKnowledge" => "thy_isac_" ^ theory'2thyID thyID ^ "-rls-" ^ rls'

  | "IsacScripts" => "thy_scri_" ^ theory'2thyID thyID ^ "-rls-" ^ rls'

  | str => error ("rls2guh called with isa = '" ^ isa ^ "' for rls = '" ^ rls' ^ "'");

fun cal2guh (isa, thyID:thyID) calID = case isa of

    "Isabelle" => "thy_isab_" ^ theory'2thyID thyID ^ "-cal-" ^ calID : guh

  | "IsacKnowledge" => "thy_isac_" ^ theory'2thyID thyID ^ "-cal-" ^ calID

  | "IsacScripts" => "thy_scri_" ^ theory'2thyID thyID ^ "-cal-" ^ calID

  | str => error ("cal2guh called with isa = '" ^ isa ^ "' for cal = '" ^ calID ^ "'");

fun ord2guh (isa, thyID:thyID) (rew_ord':rew_ord') = case isa of

    "Isabelle" => "thy_isab_" ^ theory'2thyID thyID ^ "-ord-" ^ rew_ord' : guh

  | "IsacKnowledge" => "thy_isac_" ^ theory'2thyID thyID ^ "-ord-" ^ rew_ord'

  | "IsacScripts" => "thy_scri_" ^ theory'2thyID thyID ^ "-ord-" ^ rew_ord'

  | str => error ("ord2guh called with isa = '" ^ isa ^ "' for ord = '" ^ rew_ord' ^ "'");

(* not only for thydata, but also for thy's etc *)

fun theID2guh (theID : theID) = case length theID of

    0 => error ("theID2guh: called with theID = " ^ strs2str' theID)

  | 1 => part2guh theID

  | 2 => thy2guh theID

  | 3 => thypart2guh theID

  | 4 => 

    let val [isa, thyID, typ, elemID] = theID

    in case typ of

        "Theorems" => thm2guh (isa, thyID) elemID

      | "Rulesets" => rls2guh (isa, thyID) elemID

      | "Calculations" => cal2guh (isa, thyID) elemID

      | "Orders" => ord2guh (isa, thyID) elemID

      | "Theorems" => thy2guh [isa, thyID]

      | str => error ("theID2guh: called with theID = " ^ strs2str' theID)

    end

  | n => error ("theID2guh called with theID = " ^ strs2str' theID);

type path = string;

type filename = string;

(*val xxx = fn: a b => (a,b);   ??? fun-definition ???*)

local

    fun ii (_:term) = e_rrlsstate;

    fun no (_:term) = SOME (e_term,[e_term]);

    fun lo (_:rule list list) (_:term) (_:rule) = [(e_rule,(e_term,[e_term]))];

    fun ne (_:rule list list) (_:term) = SOME e_rule;

    fun fo (_:rule list list) (_:term) (_:term) = [(e_rule,(e_term,[e_term]))];

in

val e_rfuns = Rfuns {init_state=ii,normal_form=no,locate_rule=lo,

		     next_rule=ne,attach_form=fo};

end;

val e_rls =

  Rls {id = "e_rls", preconds = [], rew_ord = ("dummy_ord", dummy_ord), erls = Erls,

    srls = Erls, calc = [], rules = [], errpatts = [], scr = EmptyScr}: rls;

val e_rrls =

  Rrls {id = "e_rrls", prepat = [], rew_ord = ("dummy_ord", dummy_ord), erls = Erls,

    calc = [], errpatts = [], scr=e_rfuns}:rls;

fun rep_rls (Rls {id,preconds,rew_ord,erls,srls,calc,errpatts,rules,scr}) =

  {id=id,preconds=preconds,rew_ord=rew_ord,erls=erls,srls=srls,calc=calc,

   (*asm_thm=asm_thm,*)rules=rules,scr=scr}

  | rep_rls (Seq {id,preconds,rew_ord,erls,srls,calc,errpatts,rules,scr}) =

  {id=id,preconds=preconds,rew_ord=rew_ord,erls=erls,srls=srls,calc=calc,

   (*asm_thm=asm_thm,*)rules=rules,scr=scr}

  | rep_rls Erls = rep_rls e_rls

  | rep_rls (Rrls {id,...})  = rep_rls e_rls

    (*error("rep_rls doesn't take apart reverse-rewrite-rule-sets: "^id)*);

(*| rep_rls (Seq {id,...})  =

    error("rep_rls doesn't take apart reverse-rewrite-rule-sets: "^id);

--1.7.03*)

fun rep_rrls (Rrls {id, calc, erls, prepat, rew_ord, errpatts,

	      scr = Rfuns {attach_form, init_state, locate_rule, next_rule, normal_form}}) =

  {id=id, calc=calc, erls=erls, prepat=prepat,

     rew_ord=rew_ord, errpatts=errpatts, attach_form=attach_form, init_state=init_state,

     locate_rule=locate_rule, next_rule=next_rule, normal_form=normal_form}

  | rep_rrls (Rls {id,...}) =

    error ("rep_rrls doesn't take apart (normal) rule-sets: "^id)

  | rep_rrls (Seq {id,...}) =

    error ("rep_rrls doesn't take apart (normal) rule-sets: "^id);

fun append_rls id (Rls {id=_,preconds=pc,rew_ord=ro,erls=er,srls=sr,calc=ca,

			rules =rs, errpatts=errpatts, scr=sc}) r =

    (Rls{id=id,preconds=pc,rew_ord=ro,erls=er,srls=sr,calc=ca,

	 rules = rs @ r, errpatts=errpatts, scr=sc}:rls)

  | append_rls id (Seq {id=_,preconds=pc,rew_ord=ro,erls=er,srls=sr,calc=ca,

			rules =rs, errpatts=errpatts, scr=sc}) r =

    (Seq{id=id,preconds=pc,rew_ord=ro,erls=er,srls=sr,calc=ca,

	 rules = rs @ r, errpatts=errpatts, scr=sc}:rls)

  | append_rls id (Rrls _) _ =

    error ("append_rls: not for reverse-rewrite-rule-set "^id);

(*. are _atomic_ rules equal ?.*)

(*WN080102 compare eqrule ?!?*)

fun eq_rule (Thm (thm1,_), Thm (thm2,_)) = thm1 = thm2

  | eq_rule (Calc (id1,_), Calc (id2,_)) = id1 = id2

  | eq_rule (Rls_ rls1, Rls_ rls2) = id_rls rls1 = id_rls rls2

  (*id_rls checks for Rls, Seq, Rrls*)

  | eq_rule _ = false;

fun merge_ids rls1 rls2 =

  let 

    val id1 = (#id o rep_rls) rls1

    val id2 = (#id o rep_rls) rls2

  in

    if id1 = id2 then id1

    else "merged_" ^ id1 ^ "_" ^ id2

  end

fun merge_rls _ Erls rls = rls

  | merge_rls _ rls Erls = rls

  | merge_rls _ (Rrls x) _ = Rrls x (* required for merging Theory_Data *)

  | merge_rls _ _ (Rrls x) = Rrls x

  | merge_rls id