来自SAP的样例：Field Symbol 的Example-技术开发专区

来自SAP的样例：Field Symbol 的Example

作者：SAP网编辑：李倩 2009-07-20 17:48 来源：IT168�

【IT168 技术文章】

Full type specification

REPORT demo_field_symbols_type .

DATA: BEGIN OF line,
         col1(1) TYPE c,
         col2(1) TYPE c VALUE 'X',
       END OF line.

FIELD-SYMBOLS <fs> LIKE line.

ASSIGN line TO <fs>.

MOVE <fs>-col2 TO <fs>-col1.

WRITE: <fs>-col1, <fs>-col2.

--------------------------------------------------------------------------------

Forcing structures

REPORT demo_field_symbols_structure .

DATA: wa(10) TYPE c VALUE '0123456789'.

DATA: BEGIN OF line1,
         col1(3) TYPE c,
         col2(2) TYPE c,
         col3(5) TYPE c,
      END OF line1.

DATA: BEGIN OF line2,
         col1(2) TYPE c,
         col2 TYPE sy-datum,
      END OF line2.

* obsolete -------------------------------------------------------------

FIELD-SYMBOLS: <f1> STRUCTURE line1 DEFAULT wa,
               <f2> STRUCTURE line2 DEFAULT wa.

* correct --------------------------------------------------------------

FIELD-SYMBOLS <f3> LIKE line1.
ASSIGN wa TO <f3> CASTING.

FIELD-SYMBOLS <f4> LIKE line2.
ASSIGN wa TO <f4> CASTING.

* ----------------------------------------------------------------------

WRITE: / <f1>-col1, <f1>-col2, <f1>-col3,
       / <f2>-col1, <f2>-col2.

SKIP.

WRITE: / <f3>-col1, <f3>-col2, <f3>-col3,
       / <f4>-col1, <f4>-col2.

--------------------------------------------------------------------------------

Static assign

REPORT demo_field_symbols_stat_assign .

FIELD-SYMBOLS: <f1> TYPE ANY, <f2> TYPE i.

DATA: text(20)  TYPE c VALUE 'Hello, how are you?',
      num       TYPE i VALUE 5,
      BEGIN OF line1,
        col1 TYPE f VALUE '1.1e+10',
        col2 TYPE i VALUE '1234',
      END OF line1,
      line2 LIKE line1.

ASSIGN text TO <f1>.
ASSIGN num TO  <f2>.
DESCRIBE FIELD <f1> LENGTH <f2>.
WRITE: / <f1>, 'has length', num.

ASSIGN line1 TO <f1>.
ASSIGN line2-col2 TO <f2>.
MOVE <f1> TO line2.
ASSIGN 'LINE2-COL2 =' TO <f1>.
WRITE: / <f1>, <f2>.

Assign with offset

REPORT demo_field_symbols_stat_as_off .

FIELD-SYMBOLS <fs> TYPE ANY.

DATA: BEGIN OF line,
        string1(10) VALUE '0123456789',
        string2(10) VALUE 'abcdefghij',
      END OF line.

WRITE / line-string1+5.

ASSIGN line-string1+5 TO <fs>.
WRITE / <fs>.

ASSIGN line-string1+5(*) TO <fs>.
WRITE / <fs>.

REPORT demo_field_symbols_stat_as_of2 .

FIELD-SYMBOLS <fs> TYPE ANY.

DATA: BEGIN OF line,
        a TYPE c VALUE '1', b TYPE c VALUE '2',
        c TYPE c VALUE '3', d TYPE c VALUE '4',
        e TYPE c VALUE '5', f TYPE c VALUE '6',
        g TYPE c VALUE '7', h TYPE c VALUE '8',
      END OF line,
      off TYPE i,
      len TYPE i VALUE 2.

DO 2 TIMES.
  off = sy-index * 3.
  ASSIGN line-a+off(len) TO <fs>.
  <fs> = 'XX'.
ENDDO.

DO 8 TIMES.
  off = sy-index - 1.
  ASSIGN line-a+off(1) TO <fs>.
  WRITE <fs>.
ENDDO.

--------------------------------------------------------------------------------
Dynamic assign

REPORT demo_field_symbols_dynami_as_2 .

TABLES sbook.

DATA: name1(20) TYPE c VALUE 'SBOOK-FLDATE',
name2(20) TYPE c VALUE 'NAME1'.

FIELD-SYMBOLS <fs> TYPE ANY.

ASSIGN TABLE FIELD (name1) TO <fs>.
WRITE: / 'SY-SUBRC:', sy-subrc.

ASSIGN TABLE FIELD (name2) TO <fs>.
WRITE: / 'SY-SUBRC:', sy-subrc.

--------------------------------------------------------------------------------

Assigning field symbols

REPORT demo_field_symbols_dynami_as_3 .

DATA: BEGIN OF s,
        a TYPE c VALUE '1', b TYPE c VALUE '2', c TYPE c VALUE '3',
        d TYPE c VALUE '4', e TYPE c VALUE '5', f TYPE c VALUE '6',
        g TYPE c VALUE '7', h TYPE c VALUE '8',
      END OF s.

DATA off TYPE i.

FIELD-SYMBOLS <fs> TYPE ANY.

ASSIGN s-a TO <fs>.

DO 4 TIMES.
  off = sy-index - 1.
  ASSIGN <fs>+off(1) TO <fs>.
  WRITE <fs>.
ENDDO.

Assigning a structure by component

REPORT demo_field_symbols_assign_comp .

DATA: BEGIN OF line,
        col1 TYPE i VALUE '11',
        col2 TYPE i VALUE '22',
        col3 TYPE i VALUE '33',
      END OF line.

DATA comp(5) TYPE c VALUE 'COL3'.

FIELD-SYMBOLS: <f1> TYPE ANY, <f2> TYPE ANY, <f3> TYPE ANY.

ASSIGN line TO <f1>.
ASSIGN comp TO <f2>.

DO 3 TIMES.
  ASSIGN COMPONENT sy-index OF STRUCTURE <f1> TO <f3>.
  WRITE <f3>.
ENDDO.

ASSIGN COMPONENT <f2> OF STRUCTURE <f1> TO <f3>.
WRITE / <f3>.

--------------------------------------------------------------------------------

Casting with field symbol type

REPORT demo_field_symbols_casting.

TYPES: BEGIN OF t_date,
          year(4)  TYPE n,
          month(2) TYPE n,
          day(2)   TYPE n,
       END OF t_date.

FIELD-SYMBOLS <fs> TYPE t_date.

ASSIGN sy-datum TO <fs> CASTING.

WRITE / sy-datum.
SKIP.
WRITE: / <fs>-year , / <fs>-month, / <fs>-day.

--------------------------------------------------------------------------------

Casting with explicit type

REPORT demo_field_symbols_casting_typ.

TYPES: BEGIN OF t_date,
          year(4)  TYPE n,
          month(2) TYPE n,
          day(2)   TYPE n,
       END OF t_date.

FIELD-SYMBOLS: <fs> TYPE ANY,
               <f>  TYPE n.

ASSIGN sy-datum TO <fs> CASTING TYPE t_date.

WRITE / sy-datum.

SKIP.

DO.
  ASSIGN COMPONENT sy-index OF STRUCTURE <fs> TO <f>.
  IF sy-subrc <> 0.
    EXIT.
  ENDIF.
  WRITE / <f>.
ENDDO.

Casting with predefined data types

REPORT demo_field_symbols_assign_type .

DATA txt(8) TYPE c VALUE '19980606'.

DATA mytype(1) VALUE 'X'.

FIELD-SYMBOLS <fs> TYPE ANY.

ASSIGN txt TO <fs>.
WRITE / <fs>.

SKIP.

* obsolete -------------------------------------------------------------

ASSIGN txt TO <fs> TYPE 'D'.
WRITE / <fs>.

ASSIGN txt TO <fs> TYPE mytype.
WRITE / <fs>.

SKIP.

* correct --------------------------------------------------------------

ASSIGN txt TO <fs> CASTING TYPE d.
WRITE / <fs>.

ASSIGN txt TO <fs> CASTING TYPE (mytype).
WRITE / <fs>.

--------------------------------------------------------------------------------

Casting decimla places

REPORT demo_field_symbols_assign_deci .

DATA: pack1 TYPE p DECIMALS 2 VALUE '400',
      pack2 TYPE p DECIMALS 2,
      pack3 TYPE p DECIMALS 2.

FIELD-SYMBOLS: <f1> TYPE ANY ,
               <f2> TYPE ANY.

WRITE: / 'PACK1', pack1.

SKIP.

* obsolete -------------------------------------------------------------

ASSIGN pack1 TO <f1> DECIMALS 1.
WRITE: / '<F1> ', <f1>.

pack2 = <f1>.
WRITE: / 'PACK2', pack2.

ASSIGN pack2 TO <f2> DECIMALS 4.
WRITE: / '<F2> ', <f2>.

pack3 = <f1> + <f2>.
WRITE: / 'PACK3', pack3.

<f2> = '1234.56789'.
WRITE: / '<F2> ', <f2>.
WRITE: / 'PACK2', pack2.

SKIP.

* correct --------------------------------------------------------------

ASSIGN pack1 TO <f1> CASTING TYPE p DECIMALS 1.
WRITE: / '<F1> ', <f1>.

pack2 = <f1>.
WRITE: / 'PACK2', pack2.

ASSIGN pack2 TO <f2> CASTING TYPE p DECIMALS 4.
WRITE: / '<F2> ', <f2>.

pack3 = <f1> + <f2>.
WRITE: / 'PACK3', pack3.

<f2> = '1234.56789'.
WRITE: / '<F2> ', <f2>.
WRITE: / 'PACK2', pack2.

Data areas for field symbols

REPORT demo_field_symbols_assign_err .

DATA: text1(10) TYPE c, text2(10) TYPE c, text3(5) TYPE c.

FIELD-SYMBOLS <fs> TYPE ANY.

DO 100 TIMES. "Runtime-Error!
ASSIGN text1+sy-index(1) TO <fs>.
ENDDO.

--------------------------------------------------------------------------------

Data references

REPORT demo_data_reference.

TYPES: BEGIN OF t_struct,
         col1 TYPE i,
         col2 TYPE i,
       END OF t_struct.

DATA: dref1 TYPE REF TO data,
      dref2 TYPE REF TO data.

FIELD-SYMBOLS: <fs1> TYPE t_struct,
               <fs2> TYPE i.

CREATE DATA dref1 TYPE t_struct.

ASSIGN dref1->* TO <fs1>.

<fs1>-col1 = 1.
<fs1>-col2 = 2.

dref2 = dref1.

ASSIGN dref2->* TO <fs2> CASTING.
WRITE / <fs2>.

GET REFERENCE OF <fs1>-col2 INTO dref2.

ASSIGN dref2->* TO <fs2>.
WRITE / <fs2>.

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