(*  Title:      HOL/Code_Setup.thy

     ID:         $Id$

     Author:     Florian Haftmann

 *)

 header {* Setup of code generators and derived tools *}

 theory Code_Setup

 imports HOL

 uses "~~/src/HOL/Tools/recfun_codegen.ML"

 begin

 subsection {* SML code generator setup *}

 setup RecfunCodegen.setup

 types_code

   "bool"  ("bool")

 attach (term_of) {*

 fun term_of_bool b = if b then HOLogic.true_const else HOLogic.false_const;

 *}

 attach (test) {*

 fun gen_bool i = one_of [false, true];

 *}

   "prop"  ("bool")

 attach (term_of) {*

 fun term_of_prop b =

   HOLogic.mk_Trueprop (if b then HOLogic.true_const else HOLogic.false_const);

 *}

 consts_code

   "Trueprop" ("(_)")

   "True"    ("true")

   "False"   ("false")

   "Not"     ("Bool.not")

   "op |"    ("(_ orelse/ _)")

   "op &"    ("(_ andalso/ _)")

   "If"      ("(if _/ then _/ else _)")

 setup {*

 let

 fun eq_codegen thy defs gr dep thyname b t =

     (case strip_comb t of

        (Const ("op =", Type (_, [Type ("fun", _), _])), _) => NONE

      | (Const ("op =", _), [t, u]) =>

           let

             val (gr', pt) = Codegen.invoke_codegen thy defs dep thyname false (gr, t);

             val (gr'', pu) = Codegen.invoke_codegen thy defs dep thyname false (gr', u);

             val (gr''', _) = Codegen.invoke_tycodegen thy defs dep thyname false (gr'', HOLogic.boolT)

           in

             SOME (gr''', Codegen.parens

               (Pretty.block [pt, Pretty.str " =", Pretty.brk 1, pu]))

           end

      | (t as Const ("op =", _), ts) => SOME (Codegen.invoke_codegen

          thy defs dep thyname b (gr, Codegen.eta_expand t ts 2))

      | _ => NONE);

 in

   Codegen.add_codegen "eq_codegen" eq_codegen

 end

 *}

 text {* Evaluation *}

 method_setup evaluation = {*

   Method.no_args (Method.SIMPLE_METHOD' (CONVERSION Codegen.evaluation_conv THEN' rtac TrueI))

 *} "solve goal by evaluation"

 subsection {* Generic code generator setup *}

 text {* using built-in Haskell equality *}

 code_class eq

   (Haskell "Eq" where "op =" \<equiv> "(==)")

 code_const "op ="

   (Haskell infixl 4 "==")

 text {* type bool *}

 lemmas [code] = imp_conv_disj

 code_type bool

   (SML "bool")

   (OCaml "bool")

   (Haskell "Bool")

 code_instance bool :: eq

   (Haskell -)

 code_const "op = \<Colon> bool \<Rightarrow> bool \<Rightarrow> bool"

   (Haskell infixl 4 "==")

 code_const True and False and Not and "op &" and "op |" and If

   (SML "true" and "false" and "not"

     and infixl 1 "andalso" and infixl 0 "orelse"

     and "!(if (_)/ then (_)/ else (_))")

   (OCaml "true" and "false" and "not"

     and infixl 4 "&&" and infixl 2 "||"

     and "!(if (_)/ then (_)/ else (_))")

   (Haskell "True" and "False" and "not"

     and infixl 3 "&&" and infixl 2 "||"

     and "!(if (_)/ then (_)/ else (_))")

 code_reserved SML

   bool true false not

 code_reserved OCaml

   bool not

 text {* code generation for undefined as exception *}

 code_const undefined

   (SML "raise/ Fail/ \"undefined\"")

   (OCaml "failwith/ \"undefined\"")

   (Haskell "error/ \"undefined\"")

 text {* Let and If *}

 lemmas [code func] = Let_def if_True if_False

 setup {*

   CodePackage.add_appconst (@{const_name Let}, CodePackage.appgen_let)

   #> CodePackage.add_appconst (@{const_name If}, CodePackage.appgen_if)

 *}

 subsection {* Evaluation oracle *}

 oracle eval_oracle ("term") = {* fn thy => fn t => 

   if CodePackage.satisfies thy (Thm.cterm_of thy (HOLogic.dest_Trueprop t)) [] 

   then t

   else HOLogic.Trueprop $ HOLogic.true_const (*dummy*)

 *}

 method_setup eval = {*

 let

   fun eval_tac thy = 

     SUBGOAL (fn (t, i) => rtac (eval_oracle thy t) i)

 in 

   Method.ctxt_args (fn ctxt => 

     Method.SIMPLE_METHOD' (eval_tac (ProofContext.theory_of ctxt)))

 end

 *} "solve goal by evaluation"

 subsection {* Normalization by evaluation *}

 method_setup normalization = {*

   Method.no_args (Method.SIMPLE_METHOD'

     (CONVERSION (ObjectLogic.judgment_conv Nbe.normalization_conv)

       THEN' resolve_tac [TrueI, refl]))

 *} "solve goal by normalization"

 end