anchor.diff:  // https://docs.microsoft.com/en-us/sql/t-sql/statements/create-endpoint-transact-sql
   
   create_endpoint:
  -    CREATE ENDPOINT endpointname endpoint_authorization endpoint_state endpoint_as_clause endpoint_for_clause 
  -     ;
  -
  -endpointname:
  -     endpoint_name=id 
  -     ;
  +    CREATE ENDPOINT endpoint_name=id endpoint_authorization? endpoint_state? endpoint_as_clause endpoint_for_clause?  
  +;
   
   endpoint_authorization:
        AUTHORIZATION login=id
  -     |
   ;
   
   endpoint_state:
        STATE EQUAL ( state=STARTED | state=STOPPED | state=DISABLED )
  -     |
   ;
   
   endpoint_as_clause:
  
positive.code: endpoint_for_clause:
       FOR SERVICE_BROKER LR_BRACKET endpoint_server_broker_clause RR_BRACKET
       |FOR DATABASE_MIRRORING LR_BRACKET endpoint_database_mirroring_clause RR_BRACKET
       |
  ;
  
  endpoint_database_mirroring_clause:
  	 endpoint_authentication_clause endpoint_encryption_clause endpoint_role_clause ;
  
  endpoint_role_clause:
          endpoint_role_clause  COMMA
  
negative.code:     ;
  
  alter_assembly_clause
      : alter_assembly_from_clause? alter_assembly_with_clause? alter_assembly_drop_clause? alter_assembly_add_clause?
      ;
  
  alter_assembly_from_clause
      : FROM (client_assembly_specifier | assembly_bits )
      ;
  
  alter_assembly_drop_clause
      : DROP ( multiple_local_files| ALL )
      ;
  
  alter_assembly_add_clause
      : ADD FILE FROM client_file_clause 
      ;
  
  alter_assembly_add_files
  