calling exist/not exist package dynamically - oracle

Question

I have a PL/SQL package as following (A piece of code):
if(IsRegisterMode)
num_result := kwp_gep.register(var_name,var_family, bool_is_incomming);
My problem is : in some environment kwp_gep package exist and IsRegisterMode flag is true so kwp_gep.register called but in another environment kwp_gep package don't exist(not necessary) and IsRegisterMode flag is false.
With above explanation in second environment main package doesn't compile and show error : kwp_gep does not exist.
My question is: What is solution for this problem? I think exist a solution for dynamically execute kwp_gep procedures.
EDIT:
kwp_gep.register has a number as return value and bool_is_incomming and boolean.

Answer 1

Option 1: Conditional Compilation
You could use conditional compilation, e.g.
$IF $$isregistermode $THEN
kwp_gep.register(var_name,var_family);
$ENDIF
When you compile the package, you'd do something like this in the environments where the package exists:
ALTER SESSION SET PLSQL_CCFLAGS = 'isregistermode:true'
Option 2: Dynamic execution
if IsRegisterMode then
execute immediate 'kwp_gep.register(:var_name,:var_family)'
using var_name, var_family;
end if;
Option 3: Stub
(as per Egor's suggestion) in the environments that don't have kwp_gep.register, create a stub that never gets called, e.g.
CREATE OR REPLACE PACKAGE kwp_gep IS
PROCEDURE register (var_name in varchar2, var_family in varchar2);
END kwp_gep;
Note that it has no package body, so it will never execute without error. In your case it doesn't matter since your flag ensures it won't get called. If it does, then you know there's a problem in that environment.