BEGIN 
    RETURN ( p_a + p_b ) / 2; 
END; 

DECLARE 
  temp_func( p_a NUMBER , p_b NUMBER) 
  RETURN NUMBER AS 
BEGIN 
  RETURN (p_a + p_b)/2 ; 
END ; 
BEGIN 
  :PAR0 := Temp_func(:PAR1,:PAR2) ; 
END ;

SQL> select 'MYAPP_'||sys_guid() from dual;
'MYAPP_'||SYS_GUID()
--------------------------------------
MYAPP_CC59A9D52B3A4CC7BD881C76AB40AD9E

create table code_user
(
    username varchar2(30) not null
  , create_date date not null
)
/
 
alter table code_user
   add constraint code_user_pk primary key (username)
/
 
create table code_snippet
(
    unique_name varchar2(30) not null
  , plsql_snippet varchar2(4000) not null
  , username varchar2(30) not null
  , user_desc varchar2(4000) not null
  , call_spec varchar2(4000) not null
)
/
 
alter table code_snippet
   add constraint code_snippet_pk primary key (unique_name)
   add constraint code_snippet_fk1 foreign key (username) references code_user
/

create sequence myseq;
 
insert into code_user values ('FDAVIDOV',sysdate);
commit;
 
declare
   snippet_name_v varchar2(30);
begin
   snippet_name_v := 'ms'||myseq.nextval;
   insert into code_snippet values
   (
       snippet_name_v
     , 'create or replace function '||snippet_name_v||' (p_a in NUMBER, p_b in NUMBER) return number is'
       ||' '||'BEGIN'
       ||' '||'  RETURN (p_a + p_b)/2 ;'
       ||' '||'END ;'
     , 'FDAVIDOV'
     , 'my first piece of code'
     , ':PAR0 := '||snippet_name_v||' (:PAR1,:PAR2);'
   )
   ;
   for r1 in (
               select *
               from code_snippet
               where unique_name = snippet_name_v
             ) loop
      begin
         execute immediate r1.plsql_snippet;
      exception when others then
         delete
         from code_snippet
         where unique_name = r1.unique_name
         ;
         raise;
      end;
   end loop;
end;
/

select * from code_user;
select * from code_snippet;
desc ms2

variable par0 number;
exec :par0 := ms2(1,2)
print par0