--- a/src/HOL/Library/Heap_Monad.thy Thu Jan 08 17:25:06 2009 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,425 +0,0 @@
-(* Title: HOL/Library/Heap_Monad.thy
- ID: $Id$
- Author: John Matthews, Galois Connections; Alexander Krauss, Lukas Bulwahn & Florian Haftmann, TU Muenchen
-*)
-
-header {* A monad with a polymorphic heap *}
-
-theory Heap_Monad
-imports Heap
-begin
-
-subsection {* The monad *}
-
-subsubsection {* Monad combinators *}
-
-datatype exception = Exn
-
-text {* Monadic heap actions either produce values
- and transform the heap, or fail *}
-datatype 'a Heap = Heap "heap \<Rightarrow> ('a + exception) \<times> heap"
-
-primrec
- execute :: "'a Heap \<Rightarrow> heap \<Rightarrow> ('a + exception) \<times> heap" where
- "execute (Heap f) = f"
-lemmas [code del] = execute.simps
-
-lemma Heap_execute [simp]:
- "Heap (execute f) = f" by (cases f) simp_all
-
-lemma Heap_eqI:
- "(\<And>h. execute f h = execute g h) \<Longrightarrow> f = g"
- by (cases f, cases g) (auto simp: expand_fun_eq)
-
-lemma Heap_eqI':
- "(\<And>h. (\<lambda>x. execute (f x) h) = (\<lambda>y. execute (g y) h)) \<Longrightarrow> f = g"
- by (auto simp: expand_fun_eq intro: Heap_eqI)
-
-lemma Heap_strip: "(\<And>f. PROP P f) \<equiv> (\<And>g. PROP P (Heap g))"
-proof
- fix g :: "heap \<Rightarrow> ('a + exception) \<times> heap"
- assume "\<And>f. PROP P f"
- then show "PROP P (Heap g)" .
-next
- fix f :: "'a Heap"
- assume assm: "\<And>g. PROP P (Heap g)"
- then have "PROP P (Heap (execute f))" .
- then show "PROP P f" by simp
-qed
-
-definition
- heap :: "(heap \<Rightarrow> 'a \<times> heap) \<Rightarrow> 'a Heap" where
- [code del]: "heap f = Heap (\<lambda>h. apfst Inl (f h))"
-
-lemma execute_heap [simp]:
- "execute (heap f) h = apfst Inl (f h)"
- by (simp add: heap_def)
-
-definition
- bindM :: "'a Heap \<Rightarrow> ('a \<Rightarrow> 'b Heap) \<Rightarrow> 'b Heap" (infixl ">>=" 54) where
- [code del]: "f >>= g = Heap (\<lambda>h. case execute f h of
- (Inl x, h') \<Rightarrow> execute (g x) h'
- | r \<Rightarrow> r)"
-
-notation
- bindM (infixl "\<guillemotright>=" 54)
-
-abbreviation
- chainM :: "'a Heap \<Rightarrow> 'b Heap \<Rightarrow> 'b Heap" (infixl ">>" 54) where
- "f >> g \<equiv> f >>= (\<lambda>_. g)"
-
-notation
- chainM (infixl "\<guillemotright>" 54)
-
-definition
- return :: "'a \<Rightarrow> 'a Heap" where
- [code del]: "return x = heap (Pair x)"
-
-lemma execute_return [simp]:
- "execute (return x) h = apfst Inl (x, h)"
- by (simp add: return_def)
-
-definition
- raise :: "string \<Rightarrow> 'a Heap" where -- {* the string is just decoration *}
- [code del]: "raise s = Heap (Pair (Inr Exn))"
-
-notation (latex output)
- "raise" ("\<^raw:{\textsf{raise}}>")
-
-lemma execute_raise [simp]:
- "execute (raise s) h = (Inr Exn, h)"
- by (simp add: raise_def)
-
-
-subsubsection {* do-syntax *}
-
-text {*
- We provide a convenient do-notation for monadic expressions
- well-known from Haskell. @{const Let} is printed
- specially in do-expressions.
-*}
-
-nonterminals do_expr
-
-syntax
- "_do" :: "do_expr \<Rightarrow> 'a"
- ("(do (_)//done)" [12] 100)
- "_bindM" :: "pttrn \<Rightarrow> 'a \<Rightarrow> do_expr \<Rightarrow> do_expr"
- ("_ <- _;//_" [1000, 13, 12] 12)
- "_chainM" :: "'a \<Rightarrow> do_expr \<Rightarrow> do_expr"
- ("_;//_" [13, 12] 12)
- "_let" :: "pttrn \<Rightarrow> 'a \<Rightarrow> do_expr \<Rightarrow> do_expr"
- ("let _ = _;//_" [1000, 13, 12] 12)
- "_nil" :: "'a \<Rightarrow> do_expr"
- ("_" [12] 12)
-
-syntax (xsymbols)
- "_bindM" :: "pttrn \<Rightarrow> 'a \<Rightarrow> do_expr \<Rightarrow> do_expr"
- ("_ \<leftarrow> _;//_" [1000, 13, 12] 12)
-syntax (latex output)
- "_do" :: "do_expr \<Rightarrow> 'a"
- ("(\<^raw:{\textsf{do}}> (_))" [12] 100)
- "_let" :: "pttrn \<Rightarrow> 'a \<Rightarrow> do_expr \<Rightarrow> do_expr"
- ("\<^raw:\textsf{let}> _ = _;//_" [1000, 13, 12] 12)
-notation (latex output)
- "return" ("\<^raw:{\textsf{return}}>")
-
-translations
- "_do f" => "f"
- "_bindM x f g" => "f \<guillemotright>= (\<lambda>x. g)"
- "_chainM f g" => "f \<guillemotright> g"
- "_let x t f" => "CONST Let t (\<lambda>x. f)"
- "_nil f" => "f"
-
-print_translation {*
-let
- fun dest_abs_eta (Abs (abs as (_, ty, _))) =
- let
- val (v, t) = Syntax.variant_abs abs;
- in (Free (v, ty), t) end
- | dest_abs_eta t =
- let
- val (v, t) = Syntax.variant_abs ("", dummyT, t $ Bound 0);
- in (Free (v, dummyT), t) end;
- fun unfold_monad (Const (@{const_syntax bindM}, _) $ f $ g) =
- let
- val (v, g') = dest_abs_eta g;
- val vs = fold_aterms (fn Free (v, _) => insert (op =) v | _ => I) v [];
- val v_used = fold_aterms
- (fn Free (w, _) => (fn s => s orelse member (op =) vs w) | _ => I) g' false;
- in if v_used then
- Const ("_bindM", dummyT) $ v $ f $ unfold_monad g'
- else
- Const ("_chainM", dummyT) $ f $ unfold_monad g'
- end
- | unfold_monad (Const (@{const_syntax chainM}, _) $ f $ g) =
- Const ("_chainM", dummyT) $ f $ unfold_monad g
- | unfold_monad (Const (@{const_syntax Let}, _) $ f $ g) =
- let
- val (v, g') = dest_abs_eta g;
- in Const ("_let", dummyT) $ v $ f $ unfold_monad g' end
- | unfold_monad (Const (@{const_syntax Pair}, _) $ f) =
- Const (@{const_syntax return}, dummyT) $ f
- | unfold_monad f = f;
- fun contains_bindM (Const (@{const_syntax bindM}, _) $ _ $ _) = true
- | contains_bindM (Const (@{const_syntax Let}, _) $ _ $ Abs (_, _, t)) =
- contains_bindM t;
- fun bindM_monad_tr' (f::g::ts) = list_comb
- (Const ("_do", dummyT) $ unfold_monad (Const (@{const_syntax bindM}, dummyT) $ f $ g), ts);
- fun Let_monad_tr' (f :: (g as Abs (_, _, g')) :: ts) = if contains_bindM g' then list_comb
- (Const ("_do", dummyT) $ unfold_monad (Const (@{const_syntax Let}, dummyT) $ f $ g), ts)
- else raise Match;
-in [
- (@{const_syntax bindM}, bindM_monad_tr'),
- (@{const_syntax Let}, Let_monad_tr')
-] end;
-*}
-
-
-subsection {* Monad properties *}
-
-subsubsection {* Monad laws *}
-
-lemma return_bind: "return x \<guillemotright>= f = f x"
- by (simp add: bindM_def return_def)
-
-lemma bind_return: "f \<guillemotright>= return = f"
-proof (rule Heap_eqI)
- fix h
- show "execute (f \<guillemotright>= return) h = execute f h"
- by (auto simp add: bindM_def return_def split: sum.splits prod.splits)
-qed
-
-lemma bind_bind: "(f \<guillemotright>= g) \<guillemotright>= h = f \<guillemotright>= (\<lambda>x. g x \<guillemotright>= h)"
- by (rule Heap_eqI) (auto simp add: bindM_def split: split: sum.splits prod.splits)
-
-lemma bind_bind': "f \<guillemotright>= (\<lambda>x. g x \<guillemotright>= h x) = f \<guillemotright>= (\<lambda>x. g x \<guillemotright>= (\<lambda>y. return (x, y))) \<guillemotright>= (\<lambda>(x, y). h x y)"
- by (rule Heap_eqI) (auto simp add: bindM_def split: split: sum.splits prod.splits)
-
-lemma raise_bind: "raise e \<guillemotright>= f = raise e"
- by (simp add: raise_def bindM_def)
-
-
-lemmas monad_simp = return_bind bind_return bind_bind raise_bind
-
-
-subsection {* Generic combinators *}
-
-definition
- liftM :: "('a \<Rightarrow> 'b) \<Rightarrow> 'a \<Rightarrow> 'b Heap"
-where
- "liftM f = return o f"
-
-definition
- compM :: "('a \<Rightarrow> 'b Heap) \<Rightarrow> ('b \<Rightarrow> 'c Heap) \<Rightarrow> 'a \<Rightarrow> 'c Heap" (infixl ">>==" 54)
-where
- "(f >>== g) = (\<lambda>x. f x \<guillemotright>= g)"
-
-notation
- compM (infixl "\<guillemotright>==" 54)
-
-lemma liftM_collapse: "liftM f x = return (f x)"
- by (simp add: liftM_def)
-
-lemma liftM_compM: "liftM f \<guillemotright>== g = g o f"
- by (auto intro: Heap_eqI' simp add: expand_fun_eq liftM_def compM_def bindM_def)
-
-lemma compM_return: "f \<guillemotright>== return = f"
- by (simp add: compM_def monad_simp)
-
-lemma compM_compM: "(f \<guillemotright>== g) \<guillemotright>== h = f \<guillemotright>== (g \<guillemotright>== h)"
- by (simp add: compM_def monad_simp)
-
-lemma liftM_bind:
- "(\<lambda>x. liftM f x \<guillemotright>= liftM g) = liftM (\<lambda>x. g (f x))"
- by (rule Heap_eqI') (simp add: monad_simp liftM_def bindM_def)
-
-lemma liftM_comp:
- "liftM f o g = liftM (f o g)"
- by (rule Heap_eqI') (simp add: liftM_def)
-
-lemmas monad_simp' = monad_simp liftM_compM compM_return
- compM_compM liftM_bind liftM_comp
-
-primrec
- mapM :: "('a \<Rightarrow> 'b Heap) \<Rightarrow> 'a list \<Rightarrow> 'b list Heap"
-where
- "mapM f [] = return []"
- | "mapM f (x#xs) = do y \<leftarrow> f x;
- ys \<leftarrow> mapM f xs;
- return (y # ys)
- done"
-
-primrec
- foldM :: "('a \<Rightarrow> 'b \<Rightarrow> 'b Heap) \<Rightarrow> 'a list \<Rightarrow> 'b \<Rightarrow> 'b Heap"
-where
- "foldM f [] s = return s"
- | "foldM f (x#xs) s = f x s \<guillemotright>= foldM f xs"
-
-definition
- assert :: "('a \<Rightarrow> bool) \<Rightarrow> 'a \<Rightarrow> 'a Heap"
-where
- "assert P x = (if P x then return x else raise (''assert''))"
-
-lemma assert_cong [fundef_cong]:
- assumes "P = P'"
- assumes "\<And>x. P' x \<Longrightarrow> f x = f' x"
- shows "(assert P x >>= f) = (assert P' x >>= f')"
- using assms by (auto simp add: assert_def return_bind raise_bind)
-
-hide (open) const heap execute
-
-
-subsection {* Code generator setup *}
-
-subsubsection {* Logical intermediate layer *}
-
-definition
- Fail :: "message_string \<Rightarrow> exception"
-where
- [code del]: "Fail s = Exn"
-
-definition
- raise_exc :: "exception \<Rightarrow> 'a Heap"
-where
- [code del]: "raise_exc e = raise []"
-
-lemma raise_raise_exc [code, code inline]:
- "raise s = raise_exc (Fail (STR s))"
- unfolding Fail_def raise_exc_def raise_def ..
-
-hide (open) const Fail raise_exc
-
-
-subsubsection {* SML and OCaml *}
-
-code_type Heap (SML "unit/ ->/ _")
-code_const Heap (SML "raise/ (Fail/ \"bare Heap\")")
-code_const "op \<guillemotright>=" (SML "!(fn/ f'_/ =>/ fn/ ()/ =>/ f'_/ (_/ ())/ ())")
-code_const return (SML "!(fn/ ()/ =>/ _)")
-code_const "Heap_Monad.Fail" (SML "Fail")
-code_const "Heap_Monad.raise_exc" (SML "!(fn/ ()/ =>/ raise/ _)")
-
-code_type Heap (OCaml "_")
-code_const Heap (OCaml "failwith/ \"bare Heap\"")
-code_const "op \<guillemotright>=" (OCaml "!(fun/ f'_/ ()/ ->/ f'_/ (_/ ())/ ())")
-code_const return (OCaml "!(fun/ ()/ ->/ _)")
-code_const "Heap_Monad.Fail" (OCaml "Failure")
-code_const "Heap_Monad.raise_exc" (OCaml "!(fun/ ()/ ->/ raise/ _)")
-
-setup {* let
- open Code_Thingol;
-
- fun lookup naming = the o Code_Thingol.lookup_const naming;
-
- fun imp_monad_bind'' bind' return' unit' ts =
- let
- val dummy_name = "";
- val dummy_type = ITyVar dummy_name;
- val dummy_case_term = IVar dummy_name;
- (*assumption: dummy values are not relevant for serialization*)
- val unitt = IConst (unit', ([], []));
- fun dest_abs ((v, ty) `|-> t, _) = ((v, ty), t)
- | dest_abs (t, ty) =
- let
- val vs = Code_Thingol.fold_varnames cons t [];
- val v = Name.variant vs "x";
- val ty' = (hd o fst o Code_Thingol.unfold_fun) ty;
- in ((v, ty'), t `$ IVar v) end;
- fun force (t as IConst (c, _) `$ t') = if c = return'
- then t' else t `$ unitt
- | force t = t `$ unitt;
- fun tr_bind' [(t1, _), (t2, ty2)] =
- let
- val ((v, ty), t) = dest_abs (t2, ty2);
- in ICase (((force t1, ty), [(IVar v, tr_bind'' t)]), dummy_case_term) end
- and tr_bind'' t = case Code_Thingol.unfold_app t
- of (IConst (c, (_, ty1 :: ty2 :: _)), [x1, x2]) => if c = bind'
- then tr_bind' [(x1, ty1), (x2, ty2)]
- else force t
- | _ => force t;
- in (dummy_name, dummy_type) `|-> ICase (((IVar dummy_name, dummy_type),
- [(unitt, tr_bind' ts)]), dummy_case_term) end
- and imp_monad_bind' bind' return' unit' (const as (c, (_, tys))) ts = if c = bind' then case (ts, tys)
- of ([t1, t2], ty1 :: ty2 :: _) => imp_monad_bind'' bind' return' unit' [(t1, ty1), (t2, ty2)]
- | ([t1, t2, t3], ty1 :: ty2 :: _) => imp_monad_bind'' bind' return' unit' [(t1, ty1), (t2, ty2)] `$ t3
- | (ts, _) => imp_monad_bind bind' return' unit' (eta_expand 2 (const, ts))
- else IConst const `$$ map (imp_monad_bind bind' return' unit') ts
- and imp_monad_bind bind' return' unit' (IConst const) = imp_monad_bind' bind' return' unit' const []
- | imp_monad_bind bind' return' unit' (t as IVar _) = t
- | imp_monad_bind bind' return' unit' (t as _ `$ _) = (case unfold_app t
- of (IConst const, ts) => imp_monad_bind' bind' return' unit' const ts
- | (t, ts) => imp_monad_bind bind' return' unit' t `$$ map (imp_monad_bind bind' return' unit') ts)
- | imp_monad_bind bind' return' unit' (v_ty `|-> t) = v_ty `|-> imp_monad_bind bind' return' unit' t
- | imp_monad_bind bind' return' unit' (ICase (((t, ty), pats), t0)) = ICase
- (((imp_monad_bind bind' return' unit' t, ty), (map o pairself) (imp_monad_bind bind' return' unit') pats), imp_monad_bind bind' return' unit' t0);
-
- fun imp_program naming = (Graph.map_nodes o map_terms_stmt)
- (imp_monad_bind (lookup naming @{const_name bindM})
- (lookup naming @{const_name return})
- (lookup naming @{const_name Unity}));
-
-in
-
- Code_Target.extend_target ("SML_imp", ("SML", imp_program))
- #> Code_Target.extend_target ("OCaml_imp", ("OCaml", imp_program))
-
-end
-*}
-
-
-code_reserved OCaml Failure raise
-
-
-subsubsection {* Haskell *}
-
-text {* Adaption layer *}
-
-code_include Haskell "STMonad"
-{*import qualified Control.Monad;
-import qualified Control.Monad.ST;
-import qualified Data.STRef;
-import qualified Data.Array.ST;
-
-type RealWorld = Control.Monad.ST.RealWorld;
-type ST s a = Control.Monad.ST.ST s a;
-type STRef s a = Data.STRef.STRef s a;
-type STArray s a = Data.Array.ST.STArray s Int a;
-
-runST :: (forall s. ST s a) -> a;
-runST s = Control.Monad.ST.runST s;
-
-newSTRef = Data.STRef.newSTRef;
-readSTRef = Data.STRef.readSTRef;
-writeSTRef = Data.STRef.writeSTRef;
-
-newArray :: (Int, Int) -> a -> ST s (STArray s a);
-newArray = Data.Array.ST.newArray;
-
-newListArray :: (Int, Int) -> [a] -> ST s (STArray s a);
-newListArray = Data.Array.ST.newListArray;
-
-lengthArray :: STArray s a -> ST s Int;
-lengthArray a = Control.Monad.liftM snd (Data.Array.ST.getBounds a);
-
-readArray :: STArray s a -> Int -> ST s a;
-readArray = Data.Array.ST.readArray;
-
-writeArray :: STArray s a -> Int -> a -> ST s ();
-writeArray = Data.Array.ST.writeArray;*}
-
-code_reserved Haskell RealWorld ST STRef Array
- runST
- newSTRef reasSTRef writeSTRef
- newArray newListArray lengthArray readArray writeArray
-
-text {* Monad *}
-
-code_type Heap (Haskell "ST/ RealWorld/ _")
-code_const Heap (Haskell "error/ \"bare Heap\"")
-code_monad "op \<guillemotright>=" Haskell
-code_const return (Haskell "return")
-code_const "Heap_Monad.Fail" (Haskell "_")
-code_const "Heap_Monad.raise_exc" (Haskell "error")
-
-end