取得一个字符串表达式的计算结果(实现方法一)

来源：互联网发布：python 自学编辑：程序博客网时间：2024/05/22 04:40

利用数据库来帮助我们计算.

REPORT  zsolar.

DATA: lv_re TYPE string.

PERFORM frm_test USING '20*(2+3)' CHANGING lv_re.
WRITE:/ lv_re.

*&---------------------------------------------------------------------*
*&      Form  frm_test
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
*      -->LV_IN      text
*      -->LV_OUT     text
*----------------------------------------------------------------------*
FORM frm_test USING lv_in CHANGING lv_out.
  DATA: code TYPE TABLE OF rssource-line,
        prog(8) TYPE c, msg(120) TYPE c, lin(3) TYPE c,
        wrd(10) TYPE c, off(3) TYPE c.
  DATA: lv_temp TYPE string.

  CONCATENATE 'SELECT' lv_in 'from mara into :lv_out' INTO lv_temp SEPARATED BY space.

  APPEND 'PROGRAM SUBPOOL.' TO code.
  APPEND 'FORM frm_string_count2 USING lv_in CHANGING lv_out.' TO code.
  APPEND 'DATA: msg TYPE string,' TO code.
  APPEND 'oref TYPE REF TO cx_sy_native_sql_error.' TO code.
  APPEND 'TRY .' TO code.
  APPEND 'EXEC SQL.' TO code.
*  APPEND 'SELECT 12*34+56 from mara into :lv_out' TO code.
  APPEND lv_temp TO code.
  APPEND 'ENDEXEC.' TO code.
  APPEND 'CATCH cx_sy_native_sql_error INTO oref.' TO code.
  APPEND 'CALL METHOD oref->get_text' TO code.
  APPEND 'RECEIVING' TO code.
  APPEND 'result = msg.' TO code.
  APPEND 'WRITE msg.' TO code.
  APPEND 'ENDTRY.' TO code.
  APPEND 'ENDFORM.' TO code.

  GENERATE SUBROUTINE POOL code NAME prog
                           MESSAGE msg
                           LINE    lin
                           WORD    wrd
                           OFFSET  off.

  IF sy-subrc EQ 0.
    PERFORM frm_string_count2 IN PROGRAM (prog) USING lv_in CHANGING lv_re IF FOUND.
  ENDIF.

ENDFORM.                    "frm_test

*&---------------------------------------------------------------------*
*&      Form  frm_string_count
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
*FORM frm_string_count2 USING lv_in CHANGING lv_out.
*  DATA: msg TYPE string,
*        oref TYPE REF TO cx_sy_native_sql_error.
*  TRY .
*      EXEC SQL.
*
*        SELECT 12*34+56 from mara into :lv_out
*
*      ENDEXEC.
*    CATCH cx_sy_native_sql_error INTO oref.
*      CALL METHOD oref->get_text
*        RECEIVING
*          result = msg.
*      WRITE msg.
*  ENDTRY.
*ENDFORM.                    "frm_string_count