(* Title: HOL/MicroJava/J/State.thy
ID: $Id$
Author: David von Oheimb
Copyright 1999 Technische Universitaet Muenchen
State for evaluation of Java expressions and statements
*)
State = TypeRel + Value +
types fields_
= "(vname \\<times> cname \\<leadsto> val)" (* field name, defining class, value *)
obj = "cname \\<times> fields_" (* class instance with class name and fields *)
constdefs
obj_ty :: "obj \\<Rightarrow> ty"
"obj_ty obj \\<equiv> Class (fst obj)"
init_vars :: "('a \\<times> ty) list \\<Rightarrow> ('a \\<leadsto> val)"
"init_vars \\<equiv> map_of o map (\\<lambda>(n,T). (n,default_val T))"
datatype xcpt (* exceptions *)
= NullPointer
| ClassCast
| OutOfMemory
types aheap = "loc \\<leadsto> obj" (* "heap" used in a translation below *)
locals = "vname \\<leadsto> val"
state (* simple state, i.e. variable contents *)
= "aheap \\<times> locals"
(* heap, local parameter including This *)
xstate (* state including exception information *)
= "xcpt option \\<times> state"
syntax
heap :: "state \\<Rightarrow> aheap"
locals :: "state \\<Rightarrow> locals"
Norm :: "state \\<Rightarrow> xstate"
translations
"heap" => "fst"
"locals" => "snd"
"Norm s" == "(None,s)"
constdefs
new_Addr :: "aheap \\<Rightarrow> loc \\<times> xcpt option"
"new_Addr h \\<equiv> \\<epsilon>(a,x). (h a = None \\<and> x = None) | x = Some OutOfMemory"
raise_if :: "bool \\<Rightarrow> xcpt \\<Rightarrow> xcpt option \\<Rightarrow> xcpt option"
"raise_if c x xo \\<equiv> if c \\<and> (xo = None) then Some x else xo"
np :: "val \\<Rightarrow> xcpt option \\<Rightarrow> xcpt option"
"np v \\<equiv> raise_if (v = Null) NullPointer"
c_hupd :: "aheap \\<Rightarrow> xstate \\<Rightarrow> xstate"
"c_hupd h'\\<equiv> \\<lambda>(xo,(h,l)). if xo = None then (None,(h',l)) else (xo,(h,l))"
cast_ok :: "'c prog \\<Rightarrow> cname \\<Rightarrow> aheap \\<Rightarrow> val \\<Rightarrow> bool"
"cast_ok G C h v \\<equiv> v = Null \\<or> G\\<turnstile>obj_ty (the (h (the_Addr v)))\\<preceq> Class C"
end