Defining error code for qualified exception using exception_init pragma

Hi, 

I have been experimenting on exception handling in oracle plsql. During my experimentation I made the following anonymous plsql block.


+<<outer_block>>+
declare
+    exc exception;    +
begin
+    <<inner_block>>+
+    declare+
+        exc exception;        +
+    begin+
+        raise outer_block.exc;+
+    exception +
+        when outer_block.exc then+
+            dbms_output.put_line('outer Exception caught ' );+
+        when inner_block.exc then+
+            dbms_output.put_line('Inner Exception caught ' );+
+    end;+
end;


When I executed the code, I got the output "outer Exception caught ".

------------------------------------------------- PLSQL Block 2 -------------------------------------------

I changed the code a little bit differently by assigning error codes to the exceptions.

+<<outer_block>>+
declare
+    exc exception;+
+    pragma exception_init(exc,-20001);+
begin
+    <<inner_block>>+
+    declare+
+        exc exception;+
+        pragma exception_init(exc,-20001);+
+    begin+
+        raise_application_error(-20001,'Error raised');+
+    exception +
+        when outer_block.exc then+
+            dbms_output.put_line('outer Exception caught ' );+
+        when inner_block.exc then+
+            dbms_output.put_line('Inner Exception caught ' );+
+    end;+
end;

When I executed the above code, I got the following error.

Error at line 1
ORA-06550: line 15, column 9:
PLS-00484: redundant exceptions 'EXC' and 'EXC' must appear in same exception handler
ORA-06550: line 5, column 1:
PL/SQL: Statement ignored

Script Terminated on line 21.

------------------------------------------------- PLSQL Block 3 -------------------------------------------


To avoid the error, I modified the code again by qualifying the exceptions with their block names. This time, I got a different error.

+<<outer_block>>+
declare
+    exc exception;+
+    pragma exception_init(outer_block.exc,-20001);+
begin
+    <<inner_block>>+
+    declare+
+        exc exception;+
+        pragma exception_init(inner_block.exc,-20001);+
+    begin+
+        raise_application_error(-20001,'Error raised');+
+    exception +
+        when outer_block.exc then+
+            dbms_output.put_line('outer Exception caught ' );+
+        when inner_block.exc then+
+            dbms_output.put_line('Inner Exception caught ' );+
+    end;+
end;


Error at line 1
ORA-06550: line 4, column 38:
PLS-00103: Encountered the symbol "." when expecting one of the following:

   ) , =>
The symbol ", was inserted before "." to continue.
ORA-06550: line 9, column 42:
PLS-00103: Encountered the symbol "." when expecting one of the following:

   ) , =>
The symbol ", was inserted before "." to continue.



Question:
Could multiple exceptions with same exception name defined across nested plsql blocks be assigned Error codes using EXCEPTION_INIT pragma? If there are errors in PLSQL blocks 2 and 3, kindly suggest.
If the same could be accomplished by some other methods, kindly explain.