(*  Title:      Tools/Code/code_simp.ML

     Author:     Florian Haftmann, TU Muenchen

 Connecting the simplifier and the code generator.

 *)

 signature CODE_SIMP =

 sig

   val map_ss: (simpset -> simpset) -> theory -> theory

   val dynamic_conv: theory -> conv

   val dynamic_tac: theory -> int -> tactic

   val dynamic_value: theory -> term -> term

   val static_conv: theory -> simpset option -> string list -> conv

   val static_tac: theory -> simpset option -> string list -> int -> tactic

   val setup: theory -> theory

 end;

 structure Code_Simp : CODE_SIMP =

 struct

 (* dedicated simpset *)

 structure Simpset = Theory_Data

 (

   type T = simpset;

   val empty = empty_ss;

   fun extend ss = Simplifier.inherit_context empty_ss ss;

   val merge = merge_ss;

 );

 val map_ss = Simpset.map;

 fun simpset_default thy = Simplifier.global_context thy o the_default (Simpset.get thy);

 (* build simpset and conversion from program *)

 fun add_stmt (Code_Thingol.Fun (_, ((_, eqs), some_cong))) ss =

       ss addsimps (map_filter (fst o snd)) eqs

       |> fold Simplifier.add_cong (the_list some_cong)

   | add_stmt (Code_Thingol.Classinst (_, (_, (classparam_instances, _)))) ss =

       ss addsimps (map (fst o snd) classparam_instances)

   | add_stmt _ ss = ss;

 val add_program = Graph.fold (add_stmt o fst o snd);

 fun rewrite_modulo thy some_ss program = Simplifier.full_rewrite

   (add_program program (simpset_default thy some_ss));

 fun conclude_tac thy some_ss = Simplifier.full_simp_tac (simpset_default thy some_ss);

 (* evaluation with dynamic code context *)

 fun dynamic_conv thy = Code_Thingol.dynamic_conv thy

   (fn _ => fn program => fn _ => fn _ => rewrite_modulo thy NONE program);

 fun dynamic_tac thy = CONVERSION (dynamic_conv thy) THEN' conclude_tac thy NONE;

 fun dynamic_value thy = snd o Logic.dest_equals o Thm.prop_of o dynamic_conv thy o Thm.cterm_of thy;

 val setup =

   Method.setup @{binding code_simp}

     (Scan.succeed (SIMPLE_METHOD' o (CHANGED_PROP oo dynamic_tac o Proof_Context.theory_of)))

     "simplification with code equations"

   #> Value.add_evaluator ("simp", dynamic_value o Proof_Context.theory_of);

 (* evaluation with static code context *)

 fun static_conv thy some_ss consts =

   Code_Thingol.static_conv_simple thy consts

     (fn program => fn _ => fn _ => rewrite_modulo thy some_ss program);

 fun static_tac thy some_ss consts = CONVERSION (static_conv thy some_ss consts)

   THEN' conclude_tac thy some_ss;

 end;