anchor.diff:  
   // https://docs.microsoft.com/en-us/sql/t-sql/statements/create-endpoint-transact-sql
   
  -create_endpoint:
  -    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:
  -AS TCP LR_BRACKET endpoint_tcp_protocol_specific_arguments RR_BRACKET
  -;
  -
  -endpoint_tcp_protocol_specific_arguments:
  -   LISTENER_PORT EQUAL port=DECIMAL endpoint_listener_ip?
  -   ;
  -
  -endpoint_listener_ip:
  -     COMMA LISTENER_IP EQUAL (ALL | ipv4_address | ipv6_address )
  -    ;
  +create_endpoint
  +   :
  +   create_endpoint_start endpoint_name=id endpoint_authorization? endpoint_state? endpoint_as_clause endpoint_for_clause?  
  +   ;
  +
  +create_endpoint_start
  +   : CREATE ENDPOINT
  +   ;
  +
  +endpoint_authorization
  +   :
  +   AUTHORIZATION login=id
  +   ;
  +
  +endpoint_state
  +   :
  +   STATE EQUAL ( state=STARTED | state=STOPPED | state=DISABLED )
  +   ;
  +
  +endpoint_as_clause
  +   :
  +   endpoint_as_clause_start endpoint_tcp_protocol_specific_arguments RR_BRACKET
  +   ;
  +
  +endpoint_as_clause_start
  +   :
  +   AS TCP LR_BRACKET
  +   ;
  +
  +endpoint_tcp_protocol_specific_arguments
  +   :
  +   endpoint_listener_port endpoint_listener_ip?
  +   ;
  +
  +endpoint_listener_port
  +   :
  +   LISTENER_PORT EQUAL port=DECIMAL
  +   ;
  +
  +endpoint_listener_ip
  +   :
  +   endpoint_listener_ip_start endpoint_listener_ip_style
  +   ;
  +
  +endpoint_listener_ip_style
  +   : ALL
  +   | ipv4_address
  +   | ipv6_address
  +   ;
  +
  +
  +endpoint_listener_ip_start
  +   :
  +   COMMA LISTENER_IP EQUAL
  +   ;
   
   ipv4_address:
      IPV4_ADDR  
  
positive.code:     ;
  
  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
      : client_file_clause (AS id)? 
      | file_bits AS id
      | COMMA alter_assembly_add_files 
      ;
  
  // need to implement
  client_file_clause
      : STRING
      ;
  
  //need to implement
  file_bits
      :
      ;
  
  alter_assembly_with_clause
      : WITH assembly_option
      ;
  
  client_assembly_specifier
  
negative.code: //https://docs.microsoft.com/en-us/sql/t-sql/statements/alter-application-role-transact-sql
  
  alter_application_role
      : alter_application_role_start application_role=id  alter_application_role_with_clause
      ;
  
  alter_application_role_start
      : ALTER APPLICATION ROLE
      ;
  
  alter_application_role_with_clause
      : alter_application_role_with
         (alter_application_role_with_name new_application_role_name=id COMMA?)
         (alter_application_role_with_password  application_role_password=STRING COMMA?)?
         (alter_application_role_with_default app_role_default_schema=id COMMA?)?
      ;
  
  alter_application_role_with
      : WITH
      ;
  
  alter_application_role_with_password
      : PASSWORD EQUAL
      ;
  
  alter_application_role_with_default
      : DEFAULT_SCHEMA EQUAL
      ;
    
  
  alter_application_role_with_name
      : NAME EQUAL
      ;
  
  alter_assembly
      : alter_assembly_start assembly_name=id alter_assembly_clause 
      ;
  
  alter_assembly_start
      :  ALTER ASSEMBLY
      ;
  
  alter_assembly_clause
  