src/HOL/Bali/Trans.thy
changeset 12925 99131847fb93
parent 12858 6214f03d6d27
child 13337 f75dfc606ac7
--- a/src/HOL/Bali/Trans.thy	Thu Feb 21 20:11:32 2002 +0100
+++ b/src/HOL/Bali/Trans.thy	Fri Feb 22 11:26:44 2002 +0100
@@ -8,118 +8,153 @@
 
 PRELIMINARY!!!!!!!!
 
+improvements over Java Specification 1.0 (cf. 15.11.4.4):
+* dynamic method lookup does not need to check the return type
+* throw raises a NullPointer exception if a null reference is given, and each
+  throw of a system exception yield a fresh exception object (was not specified)
+* if there is not enough memory even to allocate an OutOfMemory exception,
+  evaluation/execution fails, i.e. simply stops (was not specified)
+
+design issues:
+* Lit expressions and Skip statements are considered completely evaluated.
+* the expr entry in rules is redundant in case of exceptions, but its full
+  inclusion helps to make the rule structure independent of exception occurence.
+* the rule format is such that the start state may contain an exception.
+  ++ faciliates exception handling (to be added later)
+  +  symmetry
+* the rules are defined carefully in order to be applicable even in not
+  type-correct situations (yielding undefined values),
+  e.g. the_Adr (Val (Bool b)) = arbitrary.
+  ++ fewer rules 
+  -  less readable because of auxiliary functions like the_Adr
+  Alternative: "defensive" evaluation throwing some InternalError exception
+               in case of (impossible, for correct programs) type mismatches
+
+simplifications:
+* just simple handling (i.e. propagation) of exceptions so far
+* dynamic method lookup does not check return type (should not be necessary)
 *)
 
 Trans = Eval +
 
 consts
-  texpr_tstmt	:: "prog \<Rightarrow> (((expr \<times> state) \<times> (expr \<times> state)) +
-		            ((stmt \<times> state) \<times> (stmt \<times> state))) set"
+  texpr_tstmt	:: "prog  (((expr  state)  (expr  state)) +
+		            ((stmt  state)  (stmt  state))) set"
 
 syntax (symbols)
-  texpr :: "[prog, expr \<times> state, expr \<times> state] \<Rightarrow> bool "("_\<turnstile>_ \<rightarrow>1 _"[61,82,82] 81)
-  tstmt :: "[prog, stmt \<times> state, stmt \<times> state] \<Rightarrow> bool "("_\<turnstile>_ \<mapsto>1 _"[61,82,82] 81)
-  Ref   :: "loc \<Rightarrow> expr"
+  texpr :: "[prog, expr  state, expr  state]  bool "("__ 1 _"[61,82,82] 81)
+  tstmt :: "[prog, stmt  state, stmt  state]  bool "("__ 1 _"[61,82,82] 81)
+  Ref   :: "loc  expr"
 
 translations
 
-  "G\<turnstile>e_s \<rightarrow>1 ex_s'" == "Inl (e_s, ex_s') \<in> texpr_tstmt G"
-  "G\<turnstile>s_s \<mapsto>1 s'_s'" == "Inr (s_s, s'_s') \<in> texpr_tstmt G"
+  "Ge_s 1 ex_s'" == "Inl (e_s, ex_s')  texpr_tstmt G"
+  "Gs_s 1 s'_s'" == "Inr (s_s, s'_s')  texpr_tstmt G"
   "Ref a" == "Lit (Addr a)"
 
+constdefs
+  
+  sub_expr_expr :: "(expr  expr)  prop"
+  "sub_expr_expr ef  (G e s e' s'. G(   e,s) 1 (   e',s') 
+				     G(ef e,s) 1 (ef e',s'))"
+
 inductive "texpr_tstmt G" intrs 
 
 (* evaluation of expression *)
   (* cf. 15.5 *)
-  XcptE	"\<lbrakk>\<forall>v. e \<noteq> Lit v\<rbrakk> \\<Longrightarrow>
-				  G\<turnstile>(e,Some xc,s) \<rightarrow>1 (Lit arbitrary,Some xc,s)"
+  XcptE	"v. e  Lit v 
+				  G(e,Some xc,s) 1 (Lit arbitrary,Some xc,s)"
 
+ CastXX "PROP sub_expr_expr (Cast T)"
+
+(*
   (* cf. 15.8.1 *)
-  NewC	"\<lbrakk>new_Addr (heap s) = Some (a,x);
-	  s' = assign (hupd[a\<mapsto>init_Obj G C]s) (x,s)\<rbrakk> \\<Longrightarrow>
-				G\<turnstile>(NewC C,None,s) \<rightarrow>1 (Ref a,s')"
+  NewC	"new_Addr (heap s) = Some (a,x);
+	  s' = assign (hupd[ainit_Obj G C]s) (x,s) 
+				G(NewC C,None,s) 1 (Ref a,s')"
 
   (* cf. 15.9.1 *)
-  NewA1	"\<lbrakk>G\<turnstile>(e,None,s) \<rightarrow>1 (e',s')\<rbrakk> \\<Longrightarrow>
-			      G\<turnstile>(New T[e],None,s) \<rightarrow>1 (New T[e'],s')"
-  NewA	"\<lbrakk>i = the_Intg i'; new_Addr (heap s) = Some (a, x);
-	  s' = assign (hupd[a\<mapsto>init_Arr T i]s)(raise_if (i<#0) NegArrSize x,s)\<rbrakk> \\<Longrightarrow>
-			G\<turnstile>(New T[Lit i'],None,s) \<rightarrow>1 (Ref a,s')"
+(*NewA1	"sub_expr_expr (NewA T)"*)
+  NewA1	"G(e,None,s) 1 (e',s') 
+			      G(New T[e],None,s) 1 (New T[e'],s')"
+  NewA	"i = the_Intg i'; new_Addr (heap s) = Some (a, x);
+	  s' = assign (hupd[ainit_Arr T i]s)(raise_if (i<#0) NegArrSize x,s) 
+			G(New T[Lit i'],None,s) 1 (Ref a,s')"
   (* cf. 15.15 *)
-  Cast1	"\<lbrakk>G\<turnstile>(e,None,s) \<rightarrow>1 (e',s')\<rbrakk> \\<Longrightarrow>
-			      G\<turnstile>(Cast T e,None,s) \<rightarrow>1 (Cast T e',s')"
-  Cast	"\<lbrakk>x'= raise_if (\<questiondown>G,s\<turnstile>v fits T) ClassCast None\<rbrakk> \\<Longrightarrow>
-		        G\<turnstile>(Cast T (Lit v),None,s) \<rightarrow>1 (Lit v,x',s)"
+  Cast1	"G(e,None,s) 1 (e',s') 
+			      G(Cast T e,None,s) 1 (Cast T e',s')"
+  Cast	"x'= raise_if (\<questiondown>G,sv fits T) ClassCast None 
+		        G(Cast T (Lit v),None,s) 1 (Lit v,x',s)"
 
   (* cf. 15.7.1 *)
-(*Lit				"G\<turnstile>(Lit v,None,s) \<rightarrow>1 (Lit v,None,s)"*)
+(*Lit				"G(Lit v,None,s) 1 (Lit v,None,s)"*)
 
   (* cf. 15.13.1, 15.2 *)
-  LAcc	"\<lbrakk>v = the (locals s vn)\<rbrakk> \\<Longrightarrow>
-			       G\<turnstile>(LAcc vn,None,s) \<rightarrow>1 (Lit v,None,s)"
+  LAcc	"v = the (locals s vn) 
+			       G(LAcc vn,None,s) 1 (Lit v,None,s)"
 
   (* cf. 15.25.1 *)
-  LAss1	"\<lbrakk>G\<turnstile>(e,None,s) \<rightarrow>1 (e',s')\<rbrakk> \\<Longrightarrow>
-				 G\<turnstile>(f vn:=e,None,s) \<rightarrow>1 (vn:=e',s')"
-  LAss			    "G\<turnstile>(f vn:=Lit v,None,s) \<rightarrow>1 (Lit v,None,lupd[vn\<mapsto>v]s)"
+  LAss1	"G(e,None,s) 1 (e',s') 
+				 G(f vn:=e,None,s) 1 (vn:=e',s')"
+  LAss			    "G(f vn:=Lit v,None,s) 1 (Lit v,None,lupd[vnv]s)"
 
   (* cf. 15.10.1, 15.2 *)
-  FAcc1	"\<lbrakk>G\<turnstile>(e,None,s) \<rightarrow>1 (e',s')\<rbrakk> \\<Longrightarrow>
-			       G\<turnstile>({T}e..fn,None,s) \<rightarrow>1 ({T}e'..fn,s')"
-  FAcc	"\<lbrakk>v = the (snd (the_Obj (heap s (the_Addr a'))) (fn,T))\<rbrakk> \\<Longrightarrow>
-			  G\<turnstile>({T}Lit a'..fn,None,s) \<rightarrow>1 (Lit v,np a' None,s)"
+  FAcc1	"G(e,None,s) 1 (e',s') 
+			       G({T}e..fn,None,s) 1 ({T}e'..fn,s')"
+  FAcc	"v = the (snd (the_Obj (heap s (the_Addr a'))) (fn,T)) 
+			  G({T}Lit a'..fn,None,s) 1 (Lit v,np a' None,s)"
 
   (* cf. 15.25.1 *)
-  FAss1	"\<lbrakk>G\<turnstile>(e1,None,s) \<rightarrow>1 (e1',s')\<rbrakk> \\<Longrightarrow>
-			  G\<turnstile>(f ({T}e1..fn):=e2,None,s) \<rightarrow>1 (f({T}e1'..fn):=e2,s')"
-  FAss2	"\<lbrakk>G\<turnstile>(e2,np a' None,s) \<rightarrow>1 (e2',s')\<rbrakk> \\<Longrightarrow>
-		      G\<turnstile>(f({T}Lit a'..fn):=e2,None,s) \<rightarrow>1 (f({T}Lit a'..fn):=e2',s')"
-  FAss	"\<lbrakk>a = the_Addr a'; (c,fs) = the_Obj (heap s a);
-	  s'= assign (hupd[a\<mapsto>Obj c (fs[(fn,T)\<mapsto>v])]s) (None,s)\<rbrakk> \\<Longrightarrow>
-		   G\<turnstile>(f({T}Lit a'..fn):=Lit v,None,s) \<rightarrow>1 (Lit v,s')"
+  FAss1	"G(e1,None,s) 1 (e1',s') 
+			  G(f ({T}e1..fn):=e2,None,s) 1 (f({T}e1'..fn):=e2,s')"
+  FAss2	"G(e2,np a' None,s) 1 (e2',s') 
+		      G(f({T}Lit a'..fn):=e2,None,s) 1 (f({T}Lit a'..fn):=e2',s')"
+  FAss	"a = the_Addr a'; (c,fs) = the_Obj (heap s a);
+	  s'= assign (hupd[aObj c (fs[(fn,T)v])]s) (None,s) 
+		   G(f({T}Lit a'..fn):=Lit v,None,s) 1 (Lit v,s')"
 
 
 
 
 
   (* cf. 15.12.1 *)
-  AAcc1	"\<lbrakk>G\<turnstile>(e1,None,s) \<rightarrow>1 (e1',s')\<rbrakk> \\<Longrightarrow>
-				G\<turnstile>(e1[e2],None,s) \<rightarrow>1 (e1'[e2],s')"
-  AAcc2	"\<lbrakk>G\<turnstile>(e2,None,s) \<rightarrow>1 (e2',s')\<rbrakk> \\<Longrightarrow>
-			    G\<turnstile>(Lit a'[e2],None,s) \<rightarrow>1 (Lit a'[e2'],s')"
-  AAcc	"\<lbrakk>vo = snd (the_Arr (heap s (the_Addr a'))) (the_Intg i');
-	  x' = raise_if (vo = None) IndOutBound (np a' None)\<rbrakk> \\<Longrightarrow>
-			G\<turnstile>(Lit a'[Lit i'],None,s) \<rightarrow>1 (Lit (the vo),x',s)"
+  AAcc1	"G(e1,None,s) 1 (e1',s') 
+				G(e1[e2],None,s) 1 (e1'[e2],s')"
+  AAcc2	"G(e2,None,s) 1 (e2',s') 
+			    G(Lit a'[e2],None,s) 1 (Lit a'[e2'],s')"
+  AAcc	"vo = snd (the_Arr (heap s (the_Addr a'))) (the_Intg i');
+	  x' = raise_if (vo = None) IndOutBound (np a' None) 
+			G(Lit a'[Lit i'],None,s) 1 (Lit (the vo),x',s)"
 
 
   (* cf. 15.11.4.1, 15.11.4.2, 15.11.4.4, 15.11.4.5, 14.15 *)
-  Call1	"\<lbrakk>G\<turnstile>(e,None,s) \<rightarrow>1 (e',s')\<rbrakk> \\<Longrightarrow>
-			  G\<turnstile>(e..mn({pT}p),None,s) \<rightarrow>1 (e'..mn({pT}p),s')"
-  Call2	"\<lbrakk>G\<turnstile>(p,None,s) \<rightarrow>1 (p',s')\<rbrakk> \\<Longrightarrow>
-		     G\<turnstile>(Lit a'..mn({pT}p),None,s) \<rightarrow>1 (Lit a'..mn({pT}p'),s')"
-  Call	"\<lbrakk>a = the_Addr a'; (md,(pn,rT),lvars,blk,res) = 
- 			   the (cmethd G (fst (the_Obj (h a))) (mn,pT))\<rbrakk> \\<Longrightarrow>
-	    G\<turnstile>(Lit a'..mn({pT}Lit pv),None,(h,l)) \<rightarrow>1 
-      (Body blk res l,np a' x,(h,init_vals lvars[This\<mapsto>a'][Super\<mapsto>a'][pn\<mapsto>pv]))"
-  Body1	"\<lbrakk>G\<turnstile>(s0,None,s) \<mapsto>1 (s0',s')\<rbrakk> \\<Longrightarrow>
-		   G\<turnstile>(Body s0    e      l,None,s) \<rightarrow>1 (Body s0'  e  l,s')"
-  Body2	"\<lbrakk>G\<turnstile>(e ,None,s) \<rightarrow>1 (e',s')\<rbrakk> \\<Longrightarrow>
-		   G\<turnstile>(Body Skip  e      l,None,s) \<rightarrow>1 (Body Skip e' l,s')"
-  Body		  "G\<turnstile>(Body Skip (Lit v) l,None,s) \<rightarrow>1 (Lit v,None,(heap s,l))"
+  Call1	"G(e,None,s) 1 (e',s') 
+			  G(e..mn({pT}p),None,s) 1 (e'..mn({pT}p),s')"
+  Call2	"G(p,None,s) 1 (p',s') 
+		     G(Lit a'..mn({pT}p),None,s) 1 (Lit a'..mn({pT}p'),s')"
+  Call	"a = the_Addr a'; (md,(pn,rT),lvars,blk,res) = 
+ 			   the (cmethd G (fst (the_Obj (h a))) (mn,pT)) 
+	    G(Lit a'..mn({pT}Lit pv),None,(h,l)) 1 
+      (Body blk res l,np a' x,(h,init_vals lvars[Thisa'][Supera'][pnpv]))"
+  Body1	"G(s0,None,s) 1 (s0',s') 
+		   G(Body s0    e      l,None,s) 1 (Body s0'  e  l,s')"
+  Body2	"G(e ,None,s) 1 (e',s') 
+		   G(Body Skip  e      l,None,s) 1 (Body Skip e' l,s')"
+  Body		  "G(Body Skip (Lit v) l,None,s) 1 (Lit v,None,(heap s,l))"
 
 (* execution of statements *)
 
   (* cf. 14.1 *)
-  XcptS	"\<lbrakk>s0 \<noteq> Skip\<rbrakk> \\<Longrightarrow>
-				 G\<turnstile>(s0,Some xc,s) \<mapsto>1 (Skip,Some xc,s)"
+  XcptS	"s0  Skip 
+				 G(s0,Some xc,s) 1 (Skip,Some xc,s)"
 
   (* cf. 14.5 *)
-(*Skip	 			 "G\<turnstile>(Skip,None,s) \<mapsto>1 (Skip,None,s)"*)
+(*Skip	 			 "G(Skip,None,s) 1 (Skip,None,s)"*)
 
   (* cf. 14.2 *)
-  Comp1	"\<lbrakk>G\<turnstile>(s1,None,s) \<mapsto>1 (s1',s')\<rbrakk> \\<Longrightarrow>
-			       G\<turnstile>(s1;; s2,None,s) \<mapsto>1 (s1';; s2,s')"
-  Comp			    "G\<turnstile>(Skip;; s2,None,s) \<mapsto>1 (s2,None,s)"
+  Comp1	"G(s1,None,s) 1 (s1',s') 
+			       G(s1;; s2,None,s) 1 (s1';; s2,s')"
+  Comp			    "G(Skip;; s2,None,s) 1 (s2,None,s)"
 
 
 
@@ -127,18 +162,20 @@
 
 
   (* cf. 14.7 *)
-  Expr1	"\<lbrakk>G\<turnstile>(e ,None,s) \<rightarrow>1 (e',s')\<rbrakk> \\<Longrightarrow>
-				G\<turnstile>(Expr e,None,s) \<mapsto>1 (Expr e',s')"
-  Expr			 "G\<turnstile>(Expr (Lit v),None,s) \<mapsto>1 (Skip,None,s)"
+  Expr1	"G(e ,None,s) 1 (e',s') 
+				G(Expr e,None,s) 1 (Expr e',s')"
+  Expr			 "G(Expr (Lit v),None,s) 1 (Skip,None,s)"
 
   (* cf. 14.8.2 *)
-  If1	"\<lbrakk>G\<turnstile>(e ,None,s) \<rightarrow>1 (e',s')\<rbrakk> \\<Longrightarrow>
-		      G\<turnstile>(If(e) s1 Else s2,None,s) \<mapsto>1 (If(e') s1 Else s2,s')"
-  If		 "G\<turnstile>(If(Lit v) s1 Else s2,None,s) \<mapsto>1 
+  If1	"G(e ,None,s) 1 (e',s') 
+		      G(If(e) s1 Else s2,None,s) 1 (If(e') s1 Else s2,s')"
+  If		 "G(If(Lit v) s1 Else s2,None,s) 1 
 		    (if the_Bool v then s1 else s2,None,s)"
 
   (* cf. 14.10, 14.10.1 *)
-  Loop			  "G\<turnstile>(While(e) s0,None,s) \<mapsto>1 
+  Loop			  "G(While(e) s0,None,s) 1 
 			     (If(e) (s0;; While(e) s0) Else Skip,None,s)"
+*)
+  con_defs "[sub_expr_expr_def]"
 
 end