(* Title: HOL/Ctr_Sugar.thy
Author: Jasmin Blanchette, TU Muenchen
Author: Dmitriy Traytel, TU Muenchen
Copyright 2012, 2013
Wrapping existing freely generated type's constructors.
*)
section \<open>Wrapping Existing Freely Generated Type's Constructors\<close>
theory Ctr_Sugar
imports HOL
keywords
"print_case_translations" :: diag and
"free_constructors" :: thy_goal
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 \<open>Tools/Ctr_Sugar/case_translation.ML\<close>
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 \<open>Tools/Ctr_Sugar/ctr_sugar_util.ML\<close>
ML_file \<open>Tools/Ctr_Sugar/ctr_sugar_tactics.ML\<close>
ML_file \<open>Tools/Ctr_Sugar/ctr_sugar_code.ML\<close>
ML_file \<open>Tools/Ctr_Sugar/ctr_sugar.ML\<close>
text \<open>Coinduction method that avoids some boilerplate compared with coinduct.\<close>
ML_file \<open>Tools/coinduction.ML\<close>
end