* MW: clarify/eliminate Isabelle/Scala add-ons (presently unused)

     diff -r /home/makarius/isabelle/repos-Isabelle2021/src/Pure/build-jars ./src/Pure/build-jars

     11a12

     >   src/Tools/isac/BridgeJEdit/isac.scala

     diff -r /home/makarius/isabelle/repos-Isabelle2021/src/Pure/Tools/scala_project.scala ./src/Pure/Tools/scala_project.scala

     76a77

     >       "src/Tools/isac/etc" -> Path.explode("isabelle.isac"),

 * MW: Skip_Proof.make_thm: theory -> term -> thm        ? could now change signature to

                          : Proof.context -> term -> thm

 * How does declare [[LI_trace = true]] and declare [[rewrite_trace = true]] work in ISABELLE_ISAC_TEST ?

 ***** some items for discussion

 * Clarify symmetric rule: Thm.apply_attribute Calculation.symmetric thm context (!?);

     ??

 * "fun pr_ord" is not required if used with @{make_string}, @{print}, @{print tracing};

     takes only static arguments ----------------^^^^^^^^^^^^^^, not value of "hd_ord (f, g)"

     ? are there better approximations to old output of (*1*) than with (*2*)

     (*1*)val _ = tracing ("hd_ord (f, g)      = " ^ ((pr_ord o hd_ord) (f, g)) );

     (*2*)val _ = @{print tracing}{a = "hd_ord (f, g)      = ", z = hd_ord (f, g)}(**)

 ***** for the few items below WN asks MW for help

 * MW: make Outer_Syntax.command..‹problem› a model for ..\<open>Example\<close>

   The model should demonstrate, how an ML syntax error is indicated in place 

   (in the string after \<^keyword>\<open>Given\<close> etc) and not on the definition as a whole. 

     - in MathEngBasic/problem "Outer_Syntax.command \<^command_keyword>\<open>problem\<close>" there are writeln

       and comments with testdata from "problem pbl_bieg : "Biegelinien"" in Biegelinie.thy

     - in MathEngBasic/problem there is guesswork ("TODO") how to reorganise "fun prep_input"

       such that errors in "Given" etc are indicated WITHIN the term.

 * MW: In Outer_Syntax.command..‹Example› help: is there a quick fix

   for successfully replacing hacked Problem.parse_cas by parse_references_input?

     (a) In addition to replacing Problem.parse_cas: How implement the optional parser:

       - Example "Diff_App/No.123 a" + NONE

       - Example "Diff_App/No.123 a" + SOME (probl_id, model_input, refs_input)

         i.e. we expect ISAC to present an empty template "Problem..Solution", but as a whole, to the user;

         see VSCode_Example.thy subsubsection \<open>Specification step by step\<close>

     How get Token.src for testing purposes?

     How can Scan.* be traced?

     (Tracing should help understanding Problem.parse_cas, Problem.parse_model_input which involve Scan.* )

 * ?How represent items, which have not yet been input?

    Note: For the purpose of user-guidance the format of requested input should be indicated!

     - proposal for how to indicate requested input: in VSCode_Example.thy subsubsection \<open>Empty Specification>

     - the trial with <fun is_empty> in Calculation.thy makes the question more precise: 

       better hack parsers or better work on ML_Syntax?

 * ?How accomplish two user-requirements by Outer_Syntax.command \<^command_keyword>\<open>Example\<close>

    (1) start a Calculation with a CAS_Cmd

    (2) start an Example from scratch, i.e. with (Formalize.empty, References.empty)

    Proposals for a solution are in test/../Test_VSCode_Example.thy

    subsubsection ‹Start Example with a CAS_Cmd›

 ***** priority of WN items is top down, most urgent/simple on top

 * WN: follow up 6: eliminate use of Thy_Info.get_theory

       follow up 7: ANSWER: represent items, which have not yet been input IN VSCode_Example.thy WITH "__"

 * WN: cleanup Problem/MethodC..prep_input

 * WN: Sub_Problem.tac_from_prog: use ctxt from pt

 * WN: in subst_adapt_to_type should ''bdv''(string) handled by Varialbe.declare_constraints

       ?why is "x" not already typed correctly (by reading strings from Formalise)?)

 * WN: improve naming in refine.sml, m-match.sml

 * WN: rename ‹ML_structure KEStore_Elems› to ‹ML_structure Know_Store›

 * WN: all UnparseC with Proof.context, cleanup unparseC.sml and calls

 * WN: review Prog_Tac:

       (*+isa==isa2*)@{term "Substitution []"};               (*Free ("Subproblem",.. ALSO Subproblem, ?!*)

       (*+isa==isa2*)@{term "Rewrite_Set ''norm_Rational''"}; (*Const ("Prog_Tac.Rewrite_Set",..*)

 * WN: KEStore_Elems.get_thes, add_thes still required for Error_Patterns, we want to eliminate thes:

     (1) Error_Pattern.T are already stored by MethodC -- place them in respective thys

     (2) Error_Pattern.fill_in stored with thm (in thes): instead introduce new Thy_Data for them.

         adapt KEStore_Elems.insert_fillpats for that purpose.

 * WN: Specify/formalise.sml is in BaseDefinitions/ AND Specify/  DELETE ONE VERSION

 * WN: Step_Specify.initialise: remove hdl in return-value, replace Step_Specify.nxt_specify_init_calc

       ? which uses initialise !?

 * WN: ? unify "no_met" with "empty_meth_id" from References.empty ?

 * WN: proper ML antiquotations for "Tactical.Try" etc. --- be careful about unclear situations,

   e.g. "Tactical.Try" vs. "Lucas_Interpreter.Try";

 * WN: ? Rational.Cancel_p; extend use of \<^theory> to \<^theory_context>

 * WN: Avoid Thm.get_name_hint and use Global_Theory.get_thm instead, get theory from References.T

     and push theory through as argument of respective functions.

 * WN: Eliminate Thy_Info.get_theory eventually: should take theory from ancestory

   within current context.

     cf. e587c45cae0f note in Build_Thydata.thy

 * WN: Check/clarify Context.theory_name vs. Context.theory_long_name.

     present ISAC assumes 2 sessions in the MathEngine, Specify and Interpret, 

     and all Isac_Knowledge is in session Isac.

     So Context.theory_name suffices

 * WN: more direct logical foundations wrt. Isabelle/HOL, eliminate many axiomatizations

     - quite often "axiomatization ..." can be turned into "lemma ... by auto"

       without further ado;

     - sometimes this requires to use more specific types / type classes;

     - sometimes this requires to use proper definitional mechanisms (e.g. 'primrec', 'fun');

     - a few "hard" cases will remain, to be reconsidered eventually (e.g. differentiation);

 * WN: eliminate argument theory from Interpret/*, e.g. (LI_Tool.tac_from_prog + see TODO.thy)

 * WN: rename Pos.* -- Pos.ints, Pos.spec, Pos.empty, Pos.ints_empty

 * WN: redesign transition from Specification to Solution: how relate 

     - Formalise.model with variants (e.g. VSCode_Example)

       reconsider separation of variants F_I, F_II, see MAWEN paper

     - !?! I_Model of MethodC          (fairly free sequence, dependent on Formalise.model)

     - !?! formal arguments of program (fixed sequence)