slightly more standard data merge: Symtax.merge (K true) avoids equality on abstract type Pretty.T and gracefully accepts overriding, Symtab.join prefers first entry as usual;
(* Title: HOL/MicroJava/J/SystemClasses.thy
Author: Gerwin Klein
Copyright 2002 Technische Universitaet Muenchen
*)
header {* \isaheader{System Classes} *}
theory SystemClasses imports Decl begin
text {*
This theory provides definitions for the @{text Object} class,
and the system exceptions.
*}
definition ObjectC :: "'c cdecl" where
"ObjectC \<equiv> (Object, (undefined,[],[]))"
definition NullPointerC :: "'c cdecl" where
"NullPointerC \<equiv> (Xcpt NullPointer, (Object,[],[]))"
definition ClassCastC :: "'c cdecl" where
"ClassCastC \<equiv> (Xcpt ClassCast, (Object,[],[]))"
definition OutOfMemoryC :: "'c cdecl" where
"OutOfMemoryC \<equiv> (Xcpt OutOfMemory, (Object,[],[]))"
definition SystemClasses :: "'c cdecl list" where
"SystemClasses \<equiv> [ObjectC, NullPointerC, ClassCastC, OutOfMemoryC]"
end