(*  Title:      HOL/Ctr_Sugar.thy

     Author:     Jasmin Blanchette, TU Muenchen

     Copyright   2012, 2013

 Wrapping existing freely generated type's constructors.

 *)

 header {* Wrapping Existing Freely Generated Type's Constructors *}

 theory Ctr_Sugar

 imports HOL

 keywords

   "print_case_translations" :: diag and

   "wrap_free_constructors" :: thy_goal and

   "no_discs_sels" and

   "rep_compat"

 begin

 consts

   case_guard :: "bool \<Rightarrow> 'a \<Rightarrow> ('a \<Rightarrow> 'b) \<Rightarrow> 'b"

   case_nil :: "'a \<Rightarrow> 'b"

   case_cons :: "('a \<Rightarrow> 'b) \<Rightarrow> ('a \<Rightarrow> 'b) \<Rightarrow> 'a \<Rightarrow> 'b"

   case_elem :: "'a \<Rightarrow> 'b \<Rightarrow> 'a \<Rightarrow> 'b"

   case_abs :: "('c \<Rightarrow> 'b) \<Rightarrow> 'b"

 declare [[coercion_args case_guard - + -]]

 declare [[coercion_args case_cons - -]]

 declare [[coercion_args case_abs -]]

 declare [[coercion_args case_elem - +]]

 ML_file "Tools/case_translation.ML"

 setup Case_Translation.setup

 lemma iffI_np: "\<lbrakk>x \<Longrightarrow> \<not> y; \<not> x \<Longrightarrow> y\<rbrakk> \<Longrightarrow> \<not> x \<longleftrightarrow> y"

 by (erule iffI) (erule contrapos_pn)

 lemma iff_contradict:

 "\<not> P \<Longrightarrow> P \<longleftrightarrow> Q \<Longrightarrow> Q \<Longrightarrow> R"

 "\<not> Q \<Longrightarrow> P \<longleftrightarrow> Q \<Longrightarrow> P \<Longrightarrow> R"

 by blast+

 ML_file "Tools/ctr_sugar_util.ML"

 ML_file "Tools/ctr_sugar_tactics.ML"

 ML_file "Tools/ctr_sugar_code.ML"

 ML_file "Tools/ctr_sugar.ML"

 end