ABAP: Check if a day ix a holiday

Here is some sample code that allows you to determine if a date passed as parameter is a holiday or a weekend day.

FORM check_if_holiday
                USING
                  value(fact_cal) LIKE scal-fcalid
                  value(holiday_cal) LIKE scal-hcalid
                  a_date TYPE d.
  FIELD-SYMBOLS :
     TYPE casdayattr.

  DATA
    days_attr_tbl TYPE STANDARD TABLE OF casdayattr.

* get the attributes for the specified day 
  CALL FUNCTION 'DAY_ATTRIBUTES_GET'
   EXPORTING
     factory_calendar                 = fact_cal      " default 'GR'
     holiday_calendar                 = holiday_cal   " default 'GR'
     date_from                        = a_date
     date_to                          = a_date
     language                         = sy-langu
*   IMPORTING
*     YEAR_OF_VALID_FROM               =
*     YEAR_OF_VALID_TO                 =
*     RETURNCODE                       =
    TABLES
      day_attributes                   = days_attr_tbl
   EXCEPTIONS
     factory_calendar_not_found       = 1
     holiday_calendar_not_found       = 2
     date_has_invalid_format          = 3
     date_inconsistency               = 4
     OTHERS                           = 5.
  IF sy-subrc <> 0.
    MESSAGE ID sy-msgid TYPE sy-msgty NUMBER sy-msgno
            WITH sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
  ENDIF.

  READ TABLE days_attr_tbl INDEX 1 ASSIGNING <day_attr>.

  IF NOT <day_attr>-holiday_id IS INITIAL.
    MESSAGE w888(sabapdocu) WITH a_date text-e05  <day_attr>-txt_long.
  ENDIF.

  IF <day_attr>-weekday = '6' OR  <day_attr>-weekday = '7'.
    MESSAGE w888(sabapdocu) WITH a_date text-e06 -weekday_l.
  ENDIF.
ENDFORM.                    " check_if_holiday

The parameters fact_cal and holiday_cal are two letter country code representations, so in my case, they may be hard coded to the value 'GR'.

A practical way to use the above would be :

On the screen flow logic

PROCESS AFTER INPUT.
 ...
    FIELD input_date
      MODULE input_date_changed ON REQUEST.

On the actual code

MODULE input_date_changed INPUT.
  PERFORM check_if_holiday USING 'GR' 'GR' input_date.
ENDMODULE.