Get selection screen params values

FORM get_in_params CHANGING cs_in_params TYPE lcl_controller=>ty_in_params.
  DATA: lt_finfo    TYPE STANDARD TABLE OF scr_info.
  CALL FUNCTION 'RS_SELSCREEN_INFO'
    EXPORTING
      report              = sy-repid
    TABLES
      field_info          = lt_finfo
    EXCEPTIONS
      no_selections       = 1
      report_not_existent = 2
      subroutine_pool     = 3
      OTHERS              = 4.
  IF sy-subrc <> 0.
* Implement suitable error handling here
  ELSE.
    LOOP AT lt_finfo INTO DATA(ls_finfo)
      WHERE dynnr = sy-dynnr.
      FIND REGEX '.*_(.*)' IN ls_finfo-name SUBMATCHES DATA(lv_fname).
      ASSIGN COMPONENT lv_fname OF STRUCTURE cs_in_params TO FIELD-SYMBOL(<param>).
      IF sy-subrc = 0.
        ASSIGN (ls_finfo-name) TO FIELD-SYMBOL(<value>).
        <param> = <value>.
      ENDIF.
    ENDLOOP.
  ENDIF.
ENDFORM.