20 ML {*

    21 fun mk_conjl props =

    22   fold (fn a => fn b =>

    23     if a = @{term True} then b else

    24     if b = @{term True} then a else

    25     HOLogic.mk_conj (a, b)) (rev props) @{term True};

    26 *}

    28 ML {*

    29 val split_conj_tac = REPEAT o etac conjE THEN' TRY o REPEAT_ALL_NEW (CHANGED o rtac conjI)

    30 *}

    31 

    32 (* Given function for buildng a goal for an input, prepares a

    33    one common goals for all the inputs and proves it by induction

    34    together *)

    35 ML {*

    36 fun prove_by_induct tys build_goal ind utac inputs ctxt =

    37 let

    38   val names = Datatype_Prop.make_tnames tys;

    39   val (names', ctxt') = Variable.variant_fixes names ctxt;

    40   val frees = map Free (names' ~~ tys);

    41   val (gls_lists, ctxt'') = fold_map (build_goal (tys ~~ frees)) inputs ctxt';

    42   val gls = flat gls_lists;

    43   fun trm_gls_map t = filter (exists_subterm (fn s => s = t)) gls;

    44   val trm_gl_lists = map trm_gls_map frees;

    45   val trm_gl_insts = map2 (fn n => fn l => [NONE, if l = [] then NONE else SOME n]) names' trm_gl_lists

    46   val trm_gls = map mk_conjl trm_gl_lists;

    47   val gl = HOLogic.mk_Trueprop (foldr1 HOLogic.mk_conj trm_gls);

    48   fun tac {context,...} = (

    49     InductTacs.induct_rules_tac context [(flat trm_gl_insts)] [ind]

    50     THEN_ALL_NEW split_conj_tac THEN_ALL_NEW utac) 1

    51   val th_loc = Goal.prove ctxt'' [] [] gl tac

    52   val ths_loc = HOLogic.conj_elims th_loc

    53   val ths = Variable.export ctxt'' ctxt ths_loc

    54 in

    55   filter (fn x => not (prop_of x = prop_of @{thm TrueI})) ths

    56 end

    57 *}

    84 end

    85 *}

    86 (* Code for transforming an inductive relation to a function *)

    87 ML {*

    88 fun rel_inj_tac dist_inj intrs elims =

    89   SOLVED' (asm_full_simp_tac (HOL_ss addsimps intrs)) ORELSE'

    90   (rtac @{thm iffI} THEN' RANGE [

    91      (eresolve_tac elims THEN_ALL_NEW

    92        asm_full_simp_tac (HOL_ss addsimps dist_inj)

    93      ),

    94      asm_full_simp_tac (HOL_ss addsimps intrs)])

    95 *}

    96 

    97 ML {*

    98 fun build_rel_inj_gl thm =

    99   let

   100     val prop = prop_of thm;

   101     val concl = HOLogic.dest_Trueprop (Logic.strip_imp_concl prop);

   102     val hyps = map HOLogic.dest_Trueprop (Logic.strip_imp_prems prop);

   103     fun list_conj l = foldr1 HOLogic.mk_conj l;

   104   in

   105     if hyps = [] then concl

   106     else HOLogic.mk_eq (concl, list_conj hyps)

   107   end;

   108 *}

   109 

   110 ML {*

   111 fun build_rel_inj intrs dist_inj elims ctxt =

   112 let

   113   val ((_, thms_imp), ctxt') = Variable.import false intrs ctxt;

   114   val gls = map (HOLogic.mk_Trueprop o build_rel_inj_gl) thms_imp;

   115   fun tac _ = rel_inj_tac dist_inj intrs elims 1;

   116   val thms = map (fn gl => Goal.prove ctxt' [] [] gl tac) gls;

   117 in

   118   Variable.export ctxt' ctxt thms