module Login;
   import CommonDataTypes.*;
   import DTScheduler.*;
   import UserRights.*;
   export *;
 

op userLogin

   in: dts:DTScheduler, uid:LoginID, passwd:Password;

   out: dts':DTScheduler;


   pre:(*is there a user in the list of users
		  * with the correct name AND password?
		  * *)
			exists (u in dts.dtsDB.udb)
			 
        		(u.log = uid) and (u.pass = passwd)
		  	;

   post: (dts.liUser.log = uid);

end userLogin;


end Login;