haftmann@24999: (*  ID:         $Id$
haftmann@24999:     Author:     Florian Haftmann, TU Muenchen
haftmann@24999: *)
haftmann@24999: 
haftmann@24999: header {* Type of indices *}
haftmann@24999: 
haftmann@24999: theory Code_Index
haftmann@24999: imports PreList
haftmann@24999: begin
haftmann@24999: 
haftmann@24999: text {*
haftmann@24999:   Indices are isomorphic to HOL @{typ int} but
haftmann@24999:   mapped to target-language builtin integers
haftmann@24999: *}
haftmann@24999: 
haftmann@24999: subsection {* Datatype of indices *}
haftmann@24999: 
haftmann@24999: datatype index = index_of_int int
haftmann@24999: 
haftmann@24999: lemmas [code func del] = index.recs index.cases
haftmann@24999: 
haftmann@24999: fun
haftmann@24999:   int_of_index :: "index \<Rightarrow> int"
haftmann@24999: where
haftmann@24999:   "int_of_index (index_of_int k) = k"
haftmann@24999: lemmas [code func del] = int_of_index.simps
haftmann@24999: 
haftmann@24999: lemma index_id [simp]:
haftmann@24999:   "index_of_int (int_of_index k) = k"
haftmann@24999:   by (cases k) simp_all
haftmann@24999: 
haftmann@24999: lemma index:
haftmann@24999:   "(\<And>k\<Colon>index. PROP P k) \<equiv> (\<And>k\<Colon>int. PROP P (index_of_int k))"
haftmann@24999: proof
haftmann@24999:   fix k :: int
haftmann@24999:   assume "\<And>k\<Colon>index. PROP P k"
haftmann@24999:   then show "PROP P (index_of_int k)" .
haftmann@24999: next
haftmann@24999:   fix k :: index
haftmann@24999:   assume "\<And>k\<Colon>int. PROP P (index_of_int k)"
haftmann@24999:   then have "PROP P (index_of_int (int_of_index k))" .
haftmann@24999:   then show "PROP P k" by simp
haftmann@24999: qed
haftmann@24999: 
haftmann@24999: lemma [code func]: "size (k\<Colon>index) = 0"
haftmann@24999:   by (cases k) simp_all
haftmann@24999: 
haftmann@24999: 
haftmann@24999: subsection {* Built-in integers as datatype on numerals *}
haftmann@24999: 
haftmann@24999: instance index :: number
haftmann@24999:   "number_of \<equiv> index_of_int" ..
haftmann@24999: 
haftmann@24999: code_datatype "number_of \<Colon> int \<Rightarrow> index"
haftmann@24999: 
haftmann@24999: lemma number_of_index_id [simp]:
haftmann@24999:   "number_of (int_of_index k) = k"
haftmann@24999:   unfolding number_of_index_def by simp
haftmann@24999: 
haftmann@24999: lemma number_of_index_shift:
haftmann@24999:   "number_of k = index_of_int (number_of k)"
haftmann@24999:   by (simp add: number_of_is_id number_of_index_def)
haftmann@24999: 
haftmann@25335: lemma int_of_index_number_of [simp]:
haftmann@25335:   "int_of_index (number_of k) = number_of k"
haftmann@25335:   unfolding number_of_index_def number_of_is_id by simp
haftmann@25335: 
haftmann@24999: 
haftmann@24999: subsection {* Basic arithmetic *}
haftmann@24999: 
haftmann@24999: instance index :: zero
haftmann@24999:   [simp]: "0 \<equiv> index_of_int 0" ..
haftmann@24999: lemmas [code func del] = zero_index_def
haftmann@24999: 
haftmann@24999: instance index :: one
haftmann@24999:   [simp]: "1 \<equiv> index_of_int 1" ..
haftmann@24999: lemmas [code func del] = one_index_def
haftmann@24999: 
haftmann@24999: instance index :: plus
haftmann@24999:   [simp]: "k + l \<equiv> index_of_int (int_of_index k + int_of_index l)" ..
haftmann@24999: lemmas [code func del] = plus_index_def
haftmann@24999: lemma plus_index_code [code func]:
haftmann@24999:   "index_of_int k + index_of_int l = index_of_int (k + l)"
haftmann@24999:   unfolding plus_index_def by simp
haftmann@24999: 
haftmann@24999: instance index :: minus
haftmann@24999:   [simp]: "- k \<equiv> index_of_int (- int_of_index k)"
haftmann@24999:   [simp]: "k - l \<equiv> index_of_int (int_of_index k - int_of_index l)" ..
haftmann@24999: lemmas [code func del] = uminus_index_def minus_index_def
haftmann@24999: lemma uminus_index_code [code func]:
haftmann@24999:   "- index_of_int k \<equiv> index_of_int (- k)"
haftmann@24999:   unfolding uminus_index_def by simp
haftmann@24999: lemma minus_index_code [code func]:
haftmann@24999:   "index_of_int k - index_of_int l = index_of_int (k - l)"
haftmann@24999:   unfolding minus_index_def by simp
haftmann@24999: 
haftmann@24999: instance index :: times
haftmann@24999:   [simp]: "k * l \<equiv> index_of_int (int_of_index k * int_of_index l)" ..
haftmann@24999: lemmas [code func del] = times_index_def
haftmann@24999: lemma times_index_code [code func]:
haftmann@24999:   "index_of_int k * index_of_int l = index_of_int (k * l)"
haftmann@24999:   unfolding times_index_def by simp
haftmann@24999: 
haftmann@24999: instance index :: ord
haftmann@24999:   [simp]: "k \<le> l \<equiv> int_of_index k \<le> int_of_index l"
haftmann@24999:   [simp]: "k < l \<equiv> int_of_index k < int_of_index l" ..
haftmann@24999: lemmas [code func del] = less_eq_index_def less_index_def
haftmann@24999: lemma less_eq_index_code [code func]:
haftmann@24999:   "index_of_int k \<le> index_of_int l \<longleftrightarrow> k \<le> l"
haftmann@24999:   unfolding less_eq_index_def by simp
haftmann@24999: lemma less_index_code [code func]:
haftmann@24999:   "index_of_int k < index_of_int l \<longleftrightarrow> k < l"
haftmann@24999:   unfolding less_index_def by simp
haftmann@24999: 
haftmann@25335: instance index :: "Divides.div"
haftmann@25335:   [simp]: "k div l \<equiv> index_of_int (int_of_index k div int_of_index l)"
haftmann@25335:   [simp]: "k mod l \<equiv> index_of_int (int_of_index k mod int_of_index l)" ..
haftmann@25335: 
haftmann@24999: instance index :: ring_1
haftmann@24999:   by default (auto simp add: left_distrib right_distrib)
haftmann@24999: 
haftmann@24999: lemma of_nat_index: "of_nat n = index_of_int (of_nat n)"
haftmann@24999: proof (induct n)
haftmann@24999:   case 0 show ?case by simp
haftmann@24999: next
haftmann@24999:   case (Suc n)
haftmann@24999:   then have "int_of_index (index_of_int (int n))
haftmann@24999:     = int_of_index (of_nat n)" by simp
haftmann@24999:   then have "int n = int_of_index (of_nat n)" by simp
haftmann@24999:   then show ?case by simp
haftmann@24999: qed
haftmann@24999: 
haftmann@24999: instance index :: number_ring
haftmann@24999:   by default
haftmann@24999:     (simp_all add: left_distrib number_of_index_def of_int_of_nat of_nat_index)
haftmann@24999: 
haftmann@24999: lemma zero_index_code [code inline, code func]:
haftmann@24999:   "(0\<Colon>index) = Numeral0"
haftmann@24999:   by simp
haftmann@24999: 
haftmann@24999: lemma one_index_code [code inline, code func]:
haftmann@24999:   "(1\<Colon>index) = Numeral1"
haftmann@24999:   by simp
haftmann@24999: 
haftmann@24999: instance index :: abs
haftmann@24999:   "\<bar>k\<bar> \<equiv> if k < 0 then -k else k" ..
haftmann@24999: 
haftmann@24999: lemma index_of_int [code func]:
haftmann@24999:   "index_of_int k = (if k = 0 then 0
haftmann@24999:     else if k = -1 then -1
haftmann@24999:     else let (l, m) = divAlg (k, 2) in 2 * index_of_int l +
haftmann@24999:       (if m = 0 then 0 else 1))"
haftmann@24999:   by (simp add: number_of_index_shift Let_def split_def divAlg_mod_div) arith
haftmann@24999: 
haftmann@25335: lemma int_of_index [code func]:
haftmann@25335:   "int_of_index k = (if k = 0 then 0
haftmann@25335:     else if k = -1 then -1
haftmann@25335:     else let l = k div 2; m = k mod 2 in 2 * int_of_index l +
haftmann@25335:       (if m = 0 then 0 else 1))"
haftmann@25335:   by (auto simp add: number_of_index_shift Let_def split_def) arith
haftmann@25335: 
haftmann@24999: 
haftmann@24999: subsection {* Conversion to and from @{typ nat} *}
haftmann@24999: 
haftmann@24999: definition
haftmann@24999:   nat_of_index :: "index \<Rightarrow> nat"
haftmann@24999: where
haftmann@24999:   [code func del]: "nat_of_index = nat o int_of_index"
haftmann@24999: 
haftmann@24999: definition
haftmann@24999:   nat_of_index_aux :: "index \<Rightarrow> nat \<Rightarrow> nat" where
haftmann@24999:   [code func del]: "nat_of_index_aux i n = nat_of_index i + n"
haftmann@24999: 
haftmann@24999: lemma nat_of_index_aux_code [code]:
haftmann@24999:   "nat_of_index_aux i n = (if i \<le> 0 then n else nat_of_index_aux (i - 1) (Suc n))"
haftmann@24999:   by (auto simp add: nat_of_index_aux_def nat_of_index_def)
haftmann@24999: 
haftmann@24999: lemma nat_of_index_code [code]:
haftmann@24999:   "nat_of_index i = nat_of_index_aux i 0"
haftmann@24999:   by (simp add: nat_of_index_aux_def)
haftmann@24999: 
haftmann@24999: definition
haftmann@24999:   index_of_nat :: "nat \<Rightarrow> index"
haftmann@24999: where
haftmann@24999:   [code func del]: "index_of_nat = index_of_int o of_nat"
haftmann@24999: 
haftmann@24999: lemma index_of_nat [code func]:
haftmann@24999:   "index_of_nat 0 = 0"
haftmann@24999:   "index_of_nat (Suc n) = index_of_nat n + 1"
haftmann@24999:   unfolding index_of_nat_def by simp_all
haftmann@24999: 
haftmann@24999: lemma index_nat_id [simp]:
haftmann@24999:   "nat_of_index (index_of_nat n) = n"
haftmann@24999:   "index_of_nat (nat_of_index i) = (if i \<le> 0 then 0 else i)"
haftmann@24999:   unfolding index_of_nat_def nat_of_index_def by simp_all
haftmann@24999: 
haftmann@24999: 
haftmann@24999: subsection {* ML interface *}
haftmann@24999: 
haftmann@24999: ML {*
haftmann@24999: structure Index =
haftmann@24999: struct
haftmann@24999: 
haftmann@24999: fun mk k = @{term index_of_int} $ HOLogic.mk_number @{typ index} k;
haftmann@24999: 
haftmann@24999: end;
haftmann@24999: *}
haftmann@24999: 
haftmann@24999: 
haftmann@24999: subsection {* Code serialization *}
haftmann@24999: 
haftmann@24999: code_type index
haftmann@24999:   (SML "int")
haftmann@24999:   (OCaml "int")
haftmann@24999:   (Haskell "Integer")
haftmann@24999: 
haftmann@24999: code_instance index :: eq
haftmann@24999:   (Haskell -)
haftmann@24999: 
haftmann@24999: setup {*
haftmann@24999:   fold (fn target => CodeTarget.add_pretty_numeral target true
haftmann@24999:     @{const_name number_index_inst.number_of_index}
haftmann@24999:     @{const_name Numeral.B0} @{const_name Numeral.B1}
haftmann@24999:     @{const_name Numeral.Pls} @{const_name Numeral.Min}
haftmann@24999:     @{const_name Numeral.Bit}
haftmann@24999:   ) ["SML", "OCaml", "Haskell"]
haftmann@24999: *}
haftmann@24999: 
haftmann@24999: code_reserved SML int
haftmann@24999: code_reserved OCaml int
haftmann@24999: 
haftmann@24999: code_const "op + \<Colon> index \<Rightarrow> index \<Rightarrow> index"
haftmann@24999:   (SML "Int.+ ((_), (_))")
haftmann@24999:   (OCaml "Pervasives.+")
haftmann@24999:   (Haskell infixl 6 "+")
haftmann@24999: 
haftmann@24999: code_const "uminus \<Colon> index \<Rightarrow> index"
haftmann@24999:   (SML "Int.~")
haftmann@24999:   (OCaml "Pervasives.~-")
haftmann@24999:   (Haskell "negate")
haftmann@24999: 
haftmann@24999: code_const "op - \<Colon> index \<Rightarrow> index \<Rightarrow> index"
haftmann@24999:   (SML "Int.- ((_), (_))")
haftmann@24999:   (OCaml "Pervasives.-")
haftmann@24999:   (Haskell infixl 6 "-")
haftmann@24999: 
haftmann@24999: code_const "op * \<Colon> index \<Rightarrow> index \<Rightarrow> index"
haftmann@24999:   (SML "Int.* ((_), (_))")
haftmann@24999:   (OCaml "Pervasives.*")
haftmann@24999:   (Haskell infixl 7 "*")
haftmann@24999: 
haftmann@24999: code_const "op = \<Colon> index \<Rightarrow> index \<Rightarrow> bool"
haftmann@24999:   (SML "!((_ : Int.int) = _)")
haftmann@24999:   (OCaml "!((_ : Pervasives.int) = _)")
haftmann@24999:   (Haskell infixl 4 "==")
haftmann@24999: 
haftmann@24999: code_const "op \<le> \<Colon> index \<Rightarrow> index \<Rightarrow> bool"
haftmann@24999:   (SML "Int.<= ((_), (_))")
haftmann@24999:   (OCaml "!((_ : Pervasives.int) <= _)")
haftmann@24999:   (Haskell infix 4 "<=")
haftmann@24999: 
haftmann@24999: code_const "op < \<Colon> index \<Rightarrow> index \<Rightarrow> bool"
haftmann@24999:   (SML "Int.< ((_), (_))")
haftmann@24999:   (OCaml "!((_ : Pervasives.int) < _)")
haftmann@24999:   (Haskell infix 4 "<")
haftmann@24999: 
haftmann@24999: code_reserved SML Int
haftmann@24999: code_reserved OCaml Pervasives
haftmann@24999: 
haftmann@24999: end