ABAP RTTS for describing a table

Table RTTS example

report ydemo1.

DATA:
   gv_vendor   type table of lfa1.

DATA:
  gs_component    TYPE abap_compdescr,
  go_typedescr    TYPE REF TO cl_abap_typedescr,
  go_strucdescr   TYPE REF TO cl_abap_structdescr,
  go_tabledescr   TYPE REF TO cl_abap_tabledescr.

START-OF-SELECTION.


  CALL METHOD cl_abap_typedescr=>describe_by_data
    EXPORTING
      p_data      = gv_vendor  " table type
    RECEIVING
      p_descr_ref = go_typedescr.  " table type

  " Casting to table type instance
  go_tabledescr ?= go_typedescr.

  " Get table line type
  CALL METHOD go_tabledescr->get_table_line_type
    RECEIVING
      p_descr_ref = go_typedescr.

  " Casting to line type instance
  go_strucdescr ?= go_typedescr.

  " Components of range
  LOOP AT go_strucdescr->components INTO gs_component.
    AT FIRST.
      WRITE: /1  'Length',
               AT 15 'Decimals',
               AT 25 'Type',
               AT 35 'Name'.
      WRITE: / syst-uline.
    ENDAT.

    WRITE: /1   gs_component-length LEFT-JUSTIFIED,
             AT 15  gs_component-decimals LEFT-JUSTIFIED,
             AT 25  gs_component-type_kind,
             AT 35  gs_component-name.
  ENDLOOP.


END-OF-SELECTION.