
haftmann@37787: (*  Title:      HOL/Imperative_HOL/Heap_Monad.thy
haftmann@26170:     Author:     John Matthews, Galois Connections; Alexander Krauss, Lukas Bulwahn & Florian Haftmann, TU Muenchen
haftmann@26170: *)
haftmann@26170: 
haftmann@37771: header {* A monad with a polymorphic heap and primitive reasoning infrastructure *}
haftmann@26170: 
haftmann@26170: theory Heap_Monad
haftmann@37964: imports Heap Monad_Syntax Code_Natural
haftmann@26170: begin
haftmann@26170: 
haftmann@26170: subsection {* The monad *}
haftmann@26170: 
haftmann@37758: subsubsection {* Monad construction *}
haftmann@26170: 
haftmann@26170: text {* Monadic heap actions either produce values
haftmann@26170:   and transform the heap, or fail *}
haftmann@37709: datatype 'a Heap = Heap "heap \<Rightarrow> ('a \<times> heap) option"
haftmann@26170: 
haftmann@37709: primrec execute :: "'a Heap \<Rightarrow> heap \<Rightarrow> ('a \<times> heap) option" where
haftmann@37709:   [code del]: "execute (Heap f) = f"
haftmann@26170: 
haftmann@37758: lemma Heap_cases [case_names succeed fail]:
haftmann@37758:   fixes f and h
haftmann@37758:   assumes succeed: "\<And>x h'. execute f h = Some (x, h') \<Longrightarrow> P"
haftmann@37758:   assumes fail: "execute f h = None \<Longrightarrow> P"
haftmann@37758:   shows P
haftmann@37758:   using assms by (cases "execute f h") auto
haftmann@37758: 
haftmann@26170: lemma Heap_execute [simp]:
haftmann@26170:   "Heap (execute f) = f" by (cases f) simp_all
haftmann@26170: 
haftmann@26170: lemma Heap_eqI:
haftmann@26170:   "(\<And>h. execute f h = execute g h) \<Longrightarrow> f = g"
haftmann@26170:     by (cases f, cases g) (auto simp: expand_fun_eq)
haftmann@26170: 
haftmann@37758: ML {* structure Execute_Simps = Named_Thms(
haftmann@37758:   val name = "execute_simps"
haftmann@37758:   val description = "simplification rules for execute"
haftmann@37758: ) *}
haftmann@37758: 
haftmann@37758: setup Execute_Simps.setup
haftmann@37758: 
haftmann@37787: lemma execute_Let [execute_simps]:
haftmann@37758:   "execute (let x = t in f x) = (let x = t in execute (f x))"
haftmann@37758:   by (simp add: Let_def)
haftmann@37758: 
haftmann@37758: 
haftmann@37758: subsubsection {* Specialised lifters *}
haftmann@37758: 
haftmann@37758: definition tap :: "(heap \<Rightarrow> 'a) \<Rightarrow> 'a Heap" where
haftmann@37758:   [code del]: "tap f = Heap (\<lambda>h. Some (f h, h))"
haftmann@37758: 
haftmann@37787: lemma execute_tap [execute_simps]:
haftmann@37758:   "execute (tap f) h = Some (f h, h)"
haftmann@37758:   by (simp add: tap_def)
haftmann@26170: 
haftmann@37709: definition heap :: "(heap \<Rightarrow> 'a \<times> heap) \<Rightarrow> 'a Heap" where
haftmann@37709:   [code del]: "heap f = Heap (Some \<circ> f)"
haftmann@26170: 
haftmann@37787: lemma execute_heap [execute_simps]:
haftmann@37709:   "execute (heap f) = Some \<circ> f"
haftmann@26170:   by (simp add: heap_def)
haftmann@26170: 
haftmann@37754: definition guard :: "(heap \<Rightarrow> bool) \<Rightarrow> (heap \<Rightarrow> 'a \<times> heap) \<Rightarrow> 'a Heap" where
haftmann@37754:   [code del]: "guard P f = Heap (\<lambda>h. if P h then Some (f h) else None)"
haftmann@37754: 
haftmann@37758: lemma execute_guard [execute_simps]:
haftmann@37754:   "\<not> P h \<Longrightarrow> execute (guard P f) h = None"
haftmann@37754:   "P h \<Longrightarrow> execute (guard P f) h = Some (f h)"
haftmann@37754:   by (simp_all add: guard_def)
haftmann@37754: 
haftmann@37758: 
haftmann@37758: subsubsection {* Predicate classifying successful computations *}
haftmann@37758: 
haftmann@37758: definition success :: "'a Heap \<Rightarrow> heap \<Rightarrow> bool" where
haftmann@37758:   "success f h \<longleftrightarrow> execute f h \<noteq> None"
haftmann@37758: 
haftmann@37758: lemma successI:
haftmann@37758:   "execute f h \<noteq> None \<Longrightarrow> success f h"
haftmann@37758:   by (simp add: success_def)
haftmann@37758: 
haftmann@37758: lemma successE:
haftmann@37758:   assumes "success f h"
haftmann@37771:   obtains r h' where "r = fst (the (execute c h))"
haftmann@37771:     and "h' = snd (the (execute c h))"
haftmann@37771:     and "execute f h \<noteq> None"
haftmann@37771:   using assms by (simp add: success_def)
haftmann@37758: 
haftmann@37758: ML {* structure Success_Intros = Named_Thms(
haftmann@37758:   val name = "success_intros"
haftmann@37758:   val description = "introduction rules for success"
haftmann@37758: ) *}
haftmann@37758: 
haftmann@37758: setup Success_Intros.setup
haftmann@37758: 
haftmann@37787: lemma success_tapI [success_intros]:
haftmann@37758:   "success (tap f) h"
haftmann@37787:   by (rule successI) (simp add: execute_simps)
haftmann@37758: 
haftmann@37787: lemma success_heapI [success_intros]:
haftmann@37758:   "success (heap f) h"
haftmann@37787:   by (rule successI) (simp add: execute_simps)
haftmann@37758: 
haftmann@37758: lemma success_guardI [success_intros]:
haftmann@37758:   "P h \<Longrightarrow> success (guard P f) h"
haftmann@37758:   by (rule successI) (simp add: execute_guard)
haftmann@37758: 
haftmann@37758: lemma success_LetI [success_intros]:
haftmann@37758:   "x = t \<Longrightarrow> success (f x) h \<Longrightarrow> success (let x = t in f x) h"
haftmann@37758:   by (simp add: Let_def)
haftmann@37758: 
haftmann@37771: lemma success_ifI:
haftmann@37771:   "(c \<Longrightarrow> success t h) \<Longrightarrow> (\<not> c \<Longrightarrow> success e h) \<Longrightarrow>
haftmann@37771:     success (if c then t else e) h"
haftmann@37771:   by (simp add: success_def)
haftmann@37771: 
haftmann@37771: 
haftmann@37771: subsubsection {* Predicate for a simple relational calculus *}
haftmann@37771: 
haftmann@37771: text {*
haftmann@37771:   The @{text crel} predicate states that when a computation @{text c}
haftmann@37771:   runs with the heap @{text h} will result in return value @{text r}
haftmann@37771:   and a heap @{text "h'"}, i.e.~no exception occurs.
haftmann@37771: *}  
haftmann@37771: 
haftmann@37771: definition crel :: "'a Heap \<Rightarrow> heap \<Rightarrow> heap \<Rightarrow> 'a \<Rightarrow> bool" where
haftmann@37878:   crel_def: "crel c h h' r \<longleftrightarrow> execute c h = Some (r, h')"
haftmann@37771: 
haftmann@37771: lemma crelI:
haftmann@37878:   "execute c h = Some (r, h') \<Longrightarrow> crel c h h' r"
haftmann@37771:   by (simp add: crel_def)
haftmann@37771: 
haftmann@37771: lemma crelE:
haftmann@37771:   assumes "crel c h h' r"
haftmann@37771:   obtains "r = fst (the (execute c h))"
haftmann@37771:     and "h' = snd (the (execute c h))"
haftmann@37771:     and "success c h"
haftmann@37771: proof (rule that)
haftmann@37771:   from assms have *: "execute c h = Some (r, h')" by (simp add: crel_def)
haftmann@37771:   then show "success c h" by (simp add: success_def)
haftmann@37771:   from * have "fst (the (execute c h)) = r" and "snd (the (execute c h)) = h'"
haftmann@37771:     by simp_all
haftmann@37771:   then show "r = fst (the (execute c h))"
haftmann@37771:     and "h' = snd (the (execute c h))" by simp_all
haftmann@37771: qed
haftmann@37771: 
haftmann@37771: lemma crel_success:
haftmann@37771:   "crel c h h' r \<Longrightarrow> success c h"
haftmann@37771:   by (simp add: crel_def success_def)
haftmann@37771: 
haftmann@37771: lemma success_crelE:
haftmann@37771:   assumes "success c h"
haftmann@37771:   obtains r h' where "crel c h h' r"
haftmann@37771:   using assms by (auto simp add: crel_def success_def)
haftmann@37771: 
haftmann@37771: lemma crel_deterministic:
haftmann@37771:   assumes "crel f h h' a"
haftmann@37771:     and "crel f h h'' b"
haftmann@37771:   shows "a = b" and "h' = h''"
haftmann@37771:   using assms unfolding crel_def by auto
haftmann@37771: 
haftmann@37771: ML {* structure Crel_Intros = Named_Thms(
haftmann@37771:   val name = "crel_intros"
haftmann@37771:   val description = "introduction rules for crel"
haftmann@37771: ) *}
haftmann@37771: 
haftmann@37771: ML {* structure Crel_Elims = Named_Thms(
haftmann@37771:   val name = "crel_elims"
haftmann@37771:   val description = "elimination rules for crel"
haftmann@37771: ) *}
haftmann@37771: 
haftmann@37771: setup "Crel_Intros.setup #> Crel_Elims.setup"
haftmann@37771: 
haftmann@37771: lemma crel_LetI [crel_intros]:
haftmann@37771:   assumes "x = t" "crel (f x) h h' r"
haftmann@37771:   shows "crel (let x = t in f x) h h' r"
haftmann@37771:   using assms by simp
haftmann@37771: 
haftmann@37771: lemma crel_LetE [crel_elims]:
haftmann@37771:   assumes "crel (let x = t in f x) h h' r"
haftmann@37771:   obtains "crel (f t) h h' r"
haftmann@37771:   using assms by simp
haftmann@37771: 
haftmann@37771: lemma crel_ifI:
haftmann@37771:   assumes "c \<Longrightarrow> crel t h h' r"
haftmann@37771:     and "\<not> c \<Longrightarrow> crel e h h' r"
haftmann@37771:   shows "crel (if c then t else e) h h' r"
haftmann@37771:   by (cases c) (simp_all add: assms)
haftmann@37771: 
haftmann@37771: lemma crel_ifE:
haftmann@37771:   assumes "crel (if c then t else e) h h' r"
haftmann@37771:   obtains "c" "crel t h h' r"
haftmann@37771:     | "\<not> c" "crel e h h' r"
haftmann@37771:   using assms by (cases c) simp_all
haftmann@37771: 
haftmann@37771: lemma crel_tapI [crel_intros]:
haftmann@37771:   assumes "h' = h" "r = f h"
haftmann@37771:   shows "crel (tap f) h h' r"
haftmann@37787:   by (rule crelI) (simp add: assms execute_simps)
haftmann@37771: 
haftmann@37771: lemma crel_tapE [crel_elims]:
haftmann@37771:   assumes "crel (tap f) h h' r"
haftmann@37771:   obtains "h' = h" and "r = f h"
haftmann@37787:   using assms by (rule crelE) (auto simp add: execute_simps)
haftmann@37771: 
haftmann@37771: lemma crel_heapI [crel_intros]:
haftmann@37771:   assumes "h' = snd (f h)" "r = fst (f h)"
haftmann@37771:   shows "crel (heap f) h h' r"
haftmann@37787:   by (rule crelI) (simp add: assms execute_simps)
haftmann@37771: 
haftmann@37771: lemma crel_heapE [crel_elims]:
haftmann@37771:   assumes "crel (heap f) h h' r"
haftmann@37771:   obtains "h' = snd (f h)" and "r = fst (f h)"
haftmann@37787:   using assms by (rule crelE) (simp add: execute_simps)
haftmann@37771: 
haftmann@37771: lemma crel_guardI [crel_intros]:
haftmann@37771:   assumes "P h" "h' = snd (f h)" "r = fst (f h)"
haftmann@37771:   shows "crel (guard P f) h h' r"
haftmann@37771:   by (rule crelI) (simp add: assms execute_simps)
haftmann@37771: 
haftmann@37771: lemma crel_guardE [crel_elims]:
haftmann@37771:   assumes "crel (guard P f) h h' r"
haftmann@37771:   obtains "h' = snd (f h)" "r = fst (f h)" "P h"
haftmann@37771:   using assms by (rule crelE)
haftmann@37771:     (auto simp add: execute_simps elim!: successE, cases "P h", auto simp add: execute_simps)
haftmann@37771: 
haftmann@37758: 
haftmann@37758: subsubsection {* Monad combinators *}
haftmann@26170: 
haftmann@37709: definition return :: "'a \<Rightarrow> 'a Heap" where
haftmann@26170:   [code del]: "return x = heap (Pair x)"
haftmann@26170: 
haftmann@37787: lemma execute_return [execute_simps]:
haftmann@37709:   "execute (return x) = Some \<circ> Pair x"
haftmann@37787:   by (simp add: return_def execute_simps)
haftmann@26170: 
haftmann@37787: lemma success_returnI [success_intros]:
haftmann@37758:   "success (return x) h"
haftmann@37787:   by (rule successI) (simp add: execute_simps)
haftmann@37758: 
haftmann@37771: lemma crel_returnI [crel_intros]:
haftmann@37771:   "h = h' \<Longrightarrow> crel (return x) h h' x"
haftmann@37787:   by (rule crelI) (simp add: execute_simps)
haftmann@37771: 
haftmann@37771: lemma crel_returnE [crel_elims]:
haftmann@37771:   assumes "crel (return x) h h' r"
haftmann@37771:   obtains "r = x" "h' = h"
haftmann@37787:   using assms by (rule crelE) (simp add: execute_simps)
haftmann@37771: 
haftmann@37709: definition raise :: "string \<Rightarrow> 'a Heap" where -- {* the string is just decoration *}
haftmann@37709:   [code del]: "raise s = Heap (\<lambda>_. None)"
haftmann@26170: 
haftmann@37787: lemma execute_raise [execute_simps]:
haftmann@37709:   "execute (raise s) = (\<lambda>_. None)"
haftmann@26170:   by (simp add: raise_def)
haftmann@26170: 
haftmann@37771: lemma crel_raiseE [crel_elims]:
haftmann@37771:   assumes "crel (raise x) h h' r"
haftmann@37771:   obtains "False"
haftmann@37787:   using assms by (rule crelE) (simp add: success_def execute_simps)
haftmann@37771: 
krauss@37792: definition bind :: "'a Heap \<Rightarrow> ('a \<Rightarrow> 'b Heap) \<Rightarrow> 'b Heap" where
krauss@37792:   [code del]: "bind f g = Heap (\<lambda>h. case execute f h of
haftmann@37709:                   Some (x, h') \<Rightarrow> execute (g x) h'
haftmann@37709:                 | None \<Rightarrow> None)"
haftmann@37709: 
krauss@37792: setup {*
krauss@37792:   Adhoc_Overloading.add_variant 
haftmann@37816:     @{const_name Monad_Syntax.bind} @{const_name Heap_Monad.bind}
krauss@37792: *}
krauss@37792: 
haftmann@37758: lemma execute_bind [execute_simps]:
haftmann@37709:   "execute f h = Some (x, h') \<Longrightarrow> execute (f \<guillemotright>= g) h = execute (g x) h'"
haftmann@37709:   "execute f h = None \<Longrightarrow> execute (f \<guillemotright>= g) h = None"
haftmann@37756:   by (simp_all add: bind_def)
haftmann@37709: 
haftmann@37771: lemma execute_bind_success:
haftmann@37771:   "success f h \<Longrightarrow> execute (f \<guillemotright>= g) h = execute (g (fst (the (execute f h)))) (snd (the (execute f h)))"
haftmann@37771:   by (cases f h rule: Heap_cases) (auto elim!: successE simp add: bind_def)
haftmann@37771: 
haftmann@37771: lemma success_bind_executeI:
haftmann@37771:   "execute f h = Some (x, h') \<Longrightarrow> success (g x) h' \<Longrightarrow> success (f \<guillemotright>= g) h"
haftmann@37758:   by (auto intro!: successI elim!: successE simp add: bind_def)
haftmann@37758: 
haftmann@37771: lemma success_bind_crelI [success_intros]:
haftmann@37771:   "crel f h h' x \<Longrightarrow> success (g x) h' \<Longrightarrow> success (f \<guillemotright>= g) h"
haftmann@37771:   by (auto simp add: crel_def success_def bind_def)
haftmann@37771: 
haftmann@37771: lemma crel_bindI [crel_intros]:
haftmann@37771:   assumes "crel f h h' r" "crel (g r) h' h'' r'"
haftmann@37771:   shows "crel (f \<guillemotright>= g) h h'' r'"
haftmann@37771:   using assms
haftmann@37771:   apply (auto intro!: crelI elim!: crelE successE)
haftmann@37771:   apply (subst execute_bind, simp_all)
haftmann@37771:   done
haftmann@37771: 
haftmann@37771: lemma crel_bindE [crel_elims]:
haftmann@37771:   assumes "crel (f \<guillemotright>= g) h h'' r'"
haftmann@37771:   obtains h' r where "crel f h h' r" "crel (g r) h' h'' r'"
haftmann@37771:   using assms by (auto simp add: crel_def bind_def split: option.split_asm)
haftmann@37771: 
haftmann@37771: lemma execute_bind_eq_SomeI:
haftmann@37878:   assumes "execute f h = Some (x, h')"
haftmann@37878:     and "execute (g x) h' = Some (y, h'')"
haftmann@37878:   shows "execute (f \<guillemotright>= g) h = Some (y, h'')"
haftmann@37756:   using assms by (simp add: bind_def)
haftmann@37754: 
haftmann@37709: lemma return_bind [simp]: "return x \<guillemotright>= f = f x"
haftmann@37787:   by (rule Heap_eqI) (simp add: execute_bind execute_simps)
haftmann@37709: 
haftmann@37709: lemma bind_return [simp]: "f \<guillemotright>= return = f"
haftmann@37787:   by (rule Heap_eqI) (simp add: bind_def execute_simps split: option.splits)
haftmann@37709: 
haftmann@37828: lemma bind_bind [simp]: "(f \<guillemotright>= g) \<guillemotright>= k = (f :: 'a Heap) \<guillemotright>= (\<lambda>x. g x \<guillemotright>= k)"
haftmann@37787:   by (rule Heap_eqI) (simp add: bind_def execute_simps split: option.splits)
haftmann@37709: 
haftmann@37709: lemma raise_bind [simp]: "raise e \<guillemotright>= f = raise e"
haftmann@37787:   by (rule Heap_eqI) (simp add: execute_simps)
haftmann@37709: 
haftmann@26170: 
haftmann@37758: subsection {* Generic combinators *}
haftmann@26170: 
haftmann@37758: subsubsection {* Assertions *}
haftmann@26170: 
haftmann@37709: definition assert :: "('a \<Rightarrow> bool) \<Rightarrow> 'a \<Rightarrow> 'a Heap" where
haftmann@37709:   "assert P x = (if P x then return x else raise ''assert'')"
haftmann@28742: 
haftmann@37758: lemma execute_assert [execute_simps]:
haftmann@37754:   "P x \<Longrightarrow> execute (assert P x) h = Some (x, h)"
haftmann@37754:   "\<not> P x \<Longrightarrow> execute (assert P x) h = None"
haftmann@37787:   by (simp_all add: assert_def execute_simps)
haftmann@37754: 
haftmann@37758: lemma success_assertI [success_intros]:
haftmann@37758:   "P x \<Longrightarrow> success (assert P x) h"
haftmann@37758:   by (rule successI) (simp add: execute_assert)
haftmann@37758: 
haftmann@37771: lemma crel_assertI [crel_intros]:
haftmann@37771:   "P x \<Longrightarrow> h' = h \<Longrightarrow> r = x \<Longrightarrow> crel (assert P x) h h' r"
haftmann@37771:   by (rule crelI) (simp add: execute_assert)
haftmann@37771:  
haftmann@37771: lemma crel_assertE [crel_elims]:
haftmann@37771:   assumes "crel (assert P x) h h' r"
haftmann@37771:   obtains "P x" "r = x" "h' = h"
haftmann@37771:   using assms by (rule crelE) (cases "P x", simp_all add: execute_assert success_def)
haftmann@37771: 
haftmann@28742: lemma assert_cong [fundef_cong]:
haftmann@28742:   assumes "P = P'"
haftmann@28742:   assumes "\<And>x. P' x \<Longrightarrow> f x = f' x"
haftmann@28742:   shows "(assert P x >>= f) = (assert P' x >>= f')"
haftmann@37754:   by (rule Heap_eqI) (insert assms, simp add: assert_def)
haftmann@28742: 
haftmann@37758: 
haftmann@37758: subsubsection {* Plain lifting *}
haftmann@37758: 
haftmann@37754: definition lift :: "('a \<Rightarrow> 'b) \<Rightarrow> 'a \<Rightarrow> 'b Heap" where
haftmann@37754:   "lift f = return o f"
haftmann@37709: 
haftmann@37754: lemma lift_collapse [simp]:
haftmann@37754:   "lift f x = return (f x)"
haftmann@37754:   by (simp add: lift_def)
haftmann@37709: 
haftmann@37754: lemma bind_lift:
haftmann@37754:   "(f \<guillemotright>= lift g) = (f \<guillemotright>= (\<lambda>x. return (g x)))"
haftmann@37754:   by (simp add: lift_def comp_def)
haftmann@37709: 
haftmann@37758: 
haftmann@37758: subsubsection {* Iteration -- warning: this is rarely useful! *}
haftmann@37758: 
haftmann@37756: primrec fold_map :: "('a \<Rightarrow> 'b Heap) \<Rightarrow> 'a list \<Rightarrow> 'b list Heap" where
haftmann@37756:   "fold_map f [] = return []"
krauss@37792: | "fold_map f (x # xs) = do {
haftmann@37709:      y \<leftarrow> f x;
haftmann@37756:      ys \<leftarrow> fold_map f xs;
haftmann@37709:      return (y # ys)
krauss@37792:    }"
haftmann@37709: 
haftmann@37756: lemma fold_map_append:
haftmann@37756:   "fold_map f (xs @ ys) = fold_map f xs \<guillemotright>= (\<lambda>xs. fold_map f ys \<guillemotright>= (\<lambda>ys. return (xs @ ys)))"
haftmann@37754:   by (induct xs) simp_all
haftmann@37754: 
haftmann@37758: lemma execute_fold_map_unchanged_heap [execute_simps]:
haftmann@37754:   assumes "\<And>x. x \<in> set xs \<Longrightarrow> \<exists>y. execute (f x) h = Some (y, h)"
haftmann@37756:   shows "execute (fold_map f xs) h =
haftmann@37754:     Some (List.map (\<lambda>x. fst (the (execute (f x) h))) xs, h)"
haftmann@37754: using assms proof (induct xs)
haftmann@37787:   case Nil show ?case by (simp add: execute_simps)
haftmann@37754: next
haftmann@37754:   case (Cons x xs)
haftmann@37754:   from Cons.prems obtain y
haftmann@37754:     where y: "execute (f x) h = Some (y, h)" by auto
haftmann@37756:   moreover from Cons.prems Cons.hyps have "execute (fold_map f xs) h =
haftmann@37754:     Some (map (\<lambda>x. fst (the (execute (f x) h))) xs, h)" by auto
haftmann@37787:   ultimately show ?case by (simp, simp only: execute_bind(1), simp add: execute_simps)
haftmann@37754: qed
haftmann@37754: 
haftmann@26182: subsection {* Code generator setup *}
haftmann@26182: 
haftmann@26182: subsubsection {* Logical intermediate layer *}
haftmann@26182: 
haftmann@37709: primrec raise' :: "String.literal \<Rightarrow> 'a Heap" where
haftmann@37709:   [code del, code_post]: "raise' (STR s) = raise s"
haftmann@26182: 
haftmann@37709: lemma raise_raise' [code_inline]:
haftmann@37709:   "raise s = raise' (STR s)"
haftmann@37709:   by simp
haftmann@26182: 
haftmann@37709: code_datatype raise' -- {* avoid @{const "Heap"} formally *}
haftmann@26182: 
haftmann@26182: 
haftmann@27707: subsubsection {* SML and OCaml *}
haftmann@26182: 
haftmann@26752: code_type Heap (SML "unit/ ->/ _")
haftmann@37828: code_const bind (SML "!(fn/ f'_/ =>/ fn/ ()/ =>/ f'_/ (_/ ())/ ())")
haftmann@27707: code_const return (SML "!(fn/ ()/ =>/ _)")
haftmann@37709: code_const Heap_Monad.raise' (SML "!(raise/ Fail/ _)")
haftmann@26182: 
haftmann@37754: code_type Heap (OCaml "unit/ ->/ _")
haftmann@37828: code_const bind (OCaml "!(fun/ f'_/ ()/ ->/ f'_/ (_/ ())/ ())")
haftmann@27707: code_const return (OCaml "!(fun/ ()/ ->/ _)")
haftmann@37828: code_const Heap_Monad.raise' (OCaml "failwith")
haftmann@27707: 
haftmann@37838: 
haftmann@37838: subsubsection {* Haskell *}
haftmann@37838: 
haftmann@37838: text {* Adaption layer *}
haftmann@37838: 
haftmann@37838: code_include Haskell "Heap"
haftmann@37838: {*import qualified Control.Monad;
haftmann@37838: import qualified Control.Monad.ST;
haftmann@37838: import qualified Data.STRef;
haftmann@37838: import qualified Data.Array.ST;
haftmann@37838: 
haftmann@37964: import Natural;
haftmann@37964: 
haftmann@37838: type RealWorld = Control.Monad.ST.RealWorld;
haftmann@37838: type ST s a = Control.Monad.ST.ST s a;
haftmann@37838: type STRef s a = Data.STRef.STRef s a;
haftmann@37964: type STArray s a = Data.Array.ST.STArray s Natural a;
haftmann@37838: 
haftmann@37838: newSTRef = Data.STRef.newSTRef;
haftmann@37838: readSTRef = Data.STRef.readSTRef;
haftmann@37838: writeSTRef = Data.STRef.writeSTRef;
haftmann@37838: 
haftmann@37964: newArray :: Natural -> a -> ST s (STArray s a);
haftmann@37838: newArray k = Data.Array.ST.newArray (0, k);
haftmann@37838: 
haftmann@37838: newListArray :: [a] -> ST s (STArray s a);
haftmann@37964: newListArray xs = Data.Array.ST.newListArray (0, (fromInteger . toInteger . length) xs) xs;
haftmann@37838: 
haftmann@37964: newFunArray :: Natural -> (Natural -> a) -> ST s (STArray s a);
haftmann@37838: newFunArray k f = Data.Array.ST.newListArray (0, k) (map f [0..k-1]);
haftmann@37838: 
haftmann@37964: lengthArray :: STArray s a -> ST s Natural;
haftmann@37838: lengthArray a = Control.Monad.liftM snd (Data.Array.ST.getBounds a);
haftmann@37838: 
haftmann@37964: readArray :: STArray s a -> Natural -> ST s a;
haftmann@37838: readArray = Data.Array.ST.readArray;
haftmann@37838: 
haftmann@37964: writeArray :: STArray s a -> Natural -> a -> ST s ();
haftmann@37838: writeArray = Data.Array.ST.writeArray;*}
haftmann@37838: 
haftmann@37838: code_reserved Haskell Heap
haftmann@37838: 
haftmann@37838: text {* Monad *}
haftmann@37838: 
haftmann@37838: code_type Heap (Haskell "Heap.ST/ Heap.RealWorld/ _")
haftmann@37838: code_monad bind Haskell
haftmann@37838: code_const return (Haskell "return")
haftmann@37838: code_const Heap_Monad.raise' (Haskell "error")
haftmann@37838: 
haftmann@37838: 
haftmann@37838: subsubsection {* Scala *}
haftmann@37838: 
haftmann@37842: code_include Scala "Heap"
haftmann@37964: {*import collection.mutable.ArraySeq
haftmann@37964: import Natural._
haftmann@37964: 
haftmann@37964: def bind[A, B](f: Unit => A, g: A => Unit => B): Unit => B = (_: Unit) => g (f ()) ()
haftmann@37842: 
haftmann@37842: class Ref[A](x: A) {
haftmann@37842:   var value = x
haftmann@37842: }
haftmann@37842: 
haftmann@37842: object Ref {
haftmann@37842:   def apply[A](x: A): Ref[A] = new Ref[A](x)
haftmann@37964:   def lookup[A](r: Ref[A]): A = r.value
haftmann@37964:   def update[A](r: Ref[A], x: A): Unit = { r.value = x }
haftmann@37842: }
haftmann@37842: 
haftmann@37964: object Array {
haftmann@37964:   def alloc[A](n: Natural)(x: A): ArraySeq[A] = ArraySeq.fill(n.as_Int)(x)
haftmann@37964:   def make[A](n: Natural)(f: Natural => A): ArraySeq[A] = ArraySeq.tabulate(n.as_Int)((k: Int) => f(Natural(k)))
haftmann@37964:   def len[A](a: ArraySeq[A]): Natural = Natural(a.length)
haftmann@37964:   def nth[A](a: ArraySeq[A], n: Natural): A = a(n.as_Int)
haftmann@37964:   def upd[A](a: ArraySeq[A], n: Natural, x: A): Unit = a.update(n.as_Int, x)
haftmann@37964:   def freeze[A](a: ArraySeq[A]): List[A] = a.toList
haftmann@37964: }*}
haftmann@37842: 
haftmann@37964: code_reserved Scala bind Ref Array
haftmann@37838: 
haftmann@37838: code_type Heap (Scala "Unit/ =>/ _")
haftmann@37878: code_const bind (Scala "bind")
haftmann@37842: code_const return (Scala "('_: Unit)/ =>/ _")
haftmann@37845: code_const Heap_Monad.raise' (Scala "!error((_))")
haftmann@37838: 
haftmann@37838: 
haftmann@37838: subsubsection {* Target variants with less units *}
haftmann@37838: 
haftmann@31871: setup {*
haftmann@31871: 
haftmann@31871: let
haftmann@27707: 
haftmann@31871: open Code_Thingol;
haftmann@31871: 
haftmann@31871: fun imp_program naming =
haftmann@27707: 
haftmann@31871:   let
haftmann@31871:     fun is_const c = case lookup_const naming c
haftmann@31871:      of SOME c' => (fn c'' => c' = c'')
haftmann@31871:       | NONE => K false;
haftmann@37756:     val is_bind = is_const @{const_name bind};
haftmann@31871:     val is_return = is_const @{const_name return};
haftmann@31893:     val dummy_name = "";
haftmann@31893:     val dummy_case_term = IVar NONE;
haftmann@31871:     (*assumption: dummy values are not relevant for serialization*)
haftmann@38057:     val (unitt, unitT) = case lookup_const naming @{const_name Unity}
haftmann@38057:      of SOME unit' => (IConst (unit', (([], []), [])), the (lookup_tyco naming @{type_name unit}) `%% [])
haftmann@31871:       | NONE => error ("Must include " ^ @{const_name Unity} ^ " in generated constants.");
haftmann@31871:     fun dest_abs ((v, ty) `|=> t, _) = ((v, ty), t)
haftmann@31871:       | dest_abs (t, ty) =
haftmann@31871:           let
haftmann@31871:             val vs = fold_varnames cons t [];
haftmann@31871:             val v = Name.variant vs "x";
haftmann@31871:             val ty' = (hd o fst o unfold_fun) ty;
haftmann@31893:           in ((SOME v, ty'), t `$ IVar (SOME v)) end;
haftmann@31871:     fun force (t as IConst (c, _) `$ t') = if is_return c
haftmann@31871:           then t' else t `$ unitt
haftmann@31871:       | force t = t `$ unitt;
haftmann@31871:     fun tr_bind' [(t1, _), (t2, ty2)] =
haftmann@31871:       let
haftmann@31871:         val ((v, ty), t) = dest_abs (t2, ty2);
haftmann@31871:       in ICase (((force t1, ty), [(IVar v, tr_bind'' t)]), dummy_case_term) end
haftmann@31871:     and tr_bind'' t = case unfold_app t
haftmann@37754:          of (IConst (c, (_, ty1 :: ty2 :: _)), [x1, x2]) => if is_bind c
haftmann@31871:               then tr_bind' [(x1, ty1), (x2, ty2)]
haftmann@31871:               else force t
haftmann@31871:           | _ => force t;
haftmann@38057:     fun imp_monad_bind'' ts = (SOME dummy_name, unitT) `|=> ICase (((IVar (SOME dummy_name), unitT),
haftmann@31871:       [(unitt, tr_bind' ts)]), dummy_case_term)
haftmann@37754:     and imp_monad_bind' (const as (c, (_, tys))) ts = if is_bind c then case (ts, tys)
haftmann@31871:        of ([t1, t2], ty1 :: ty2 :: _) => imp_monad_bind'' [(t1, ty1), (t2, ty2)]
haftmann@31871:         | ([t1, t2, t3], ty1 :: ty2 :: _) => imp_monad_bind'' [(t1, ty1), (t2, ty2)] `$ t3
haftmann@31871:         | (ts, _) => imp_monad_bind (eta_expand 2 (const, ts))
haftmann@31871:       else IConst const `$$ map imp_monad_bind ts
haftmann@31871:     and imp_monad_bind (IConst const) = imp_monad_bind' const []
haftmann@31871:       | imp_monad_bind (t as IVar _) = t
haftmann@31871:       | imp_monad_bind (t as _ `$ _) = (case unfold_app t
haftmann@31871:          of (IConst const, ts) => imp_monad_bind' const ts
haftmann@31871:           | (t, ts) => imp_monad_bind t `$$ map imp_monad_bind ts)
haftmann@31871:       | imp_monad_bind (v_ty `|=> t) = v_ty `|=> imp_monad_bind t
haftmann@31871:       | imp_monad_bind (ICase (((t, ty), pats), t0)) = ICase
haftmann@31871:           (((imp_monad_bind t, ty),
haftmann@31871:             (map o pairself) imp_monad_bind pats),
haftmann@31871:               imp_monad_bind t0);
haftmann@28663: 
haftmann@31871:   in (Graph.map_nodes o map_terms_stmt) imp_monad_bind end;
haftmann@27707: 
haftmann@27707: in
haftmann@27707: 
haftmann@31871: Code_Target.extend_target ("SML_imp", ("SML", imp_program))
haftmann@31871: #> Code_Target.extend_target ("OCaml_imp", ("OCaml", imp_program))
haftmann@37838: #> Code_Target.extend_target ("Scala_imp", ("Scala", imp_program))
haftmann@27707: 
haftmann@27707: end
haftmann@31871: 
haftmann@27707: *}
haftmann@27707: 
haftmann@26182: 
haftmann@37758: hide_const (open) Heap heap guard raise' fold_map
haftmann@37724: 
haftmann@26170: end




