0x04-关于 ABAP 的代码缩进风格的思考

description: ABAP 代码缩进风格参考

1. Introduction¶

ABAP 的代码缩进不同于许多其它语言，因为语法的原因可能导致一行代码超级长，也可能是因为缩进的原因导致排版不一致

建议写 ABAP 的时候用两个空格缩进而不是 TAB

Example

+ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx = xxxxx(
+   xxx  = xxx
+   xxxx = xxxx 
+ ).

- xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx =
-   xxxxx(
-     xxx  = xxx
-     xxxx = xxxx ).

如果换行，缩进在参数的下方

+ DATA(sum) = add_two_numbers(
+                 value_1 = 5
+                 value_2 = 6 ).

+ DATA(result) = merge_structures( a = VALUE #( field_1 = 'X'
+                                               field_2 = 'A' )
+                                  b = NEW /clean/structure_type( field_3 = 'C'
+                                                                 field_4 = 'D' ) ).

- DATA(sum) = add_two_numbers(
-     value_1 = 5
-     value_2 = 6 ).

关键字用两个空格缩进，参数用四个空格

+ DATA(sum) = add_two_numbers(
+               EXPORTING
+                 value_1 = 5
+                 value_2 = 6
+               CHANGING
+                 errors  = errors ).

- DATA(sum) = add_two_numbers(
-                 EXPORTING
-                     value_1 = 5
-                     value_2 = 6
-                 CHANGING
-                     errors  = errors ).

2. Statements¶

2.1 TYPE Statement¶

变量定义不必对齐 TYPE 关键字

+ DATA name   TYPE seoclsname.
+ DATA reader TYPE REF TO /clean/reader.

- DATA name   TYPE seoclsname.
- DATA reader TYPE REF TO /clean/reader.

DATA(ptab) = VALUE abap_parmbind_tab( ( name  = 'USERNAME'
                                        kind  = cl_abap_objectdescr=>exporting
                                        value = REF #( sy-uname ) )
                                      ( name  = 'RESULT'
                                        kind  = cl_abap_objectdescr=>returning
                                        value = REF #( <profiles> ) ) ).

2.2 IF Statement¶

+ IF X EQ 1
+   AND X NE 2.
+   ...
+ ENDIF.

- IF X EQ 1 AND X NE 2.
-   ...
- ENDIF.

IF result IS INITIAL.
  result = config

ELSEIF result-prio = config-prio AND
    result-threshold GE config-threshold.
  result = config

ELSEIF result-threshold LE config-threshold AND
       ( ( result-prio = 'W' AND config-prio = 'E' ) OR
         ( result-prio = 'N' AND config-prio = 'E' ) OR
         ( result-prio = 'N' AND config-prio = 'W' ) ).
  result = config.
ENDIF.

2.3 LOOP Statement¶

+ LOOP itab INTO DATA(line)
+   WHERE field NE `name`.
+   ...
+ ENDLOOP.

- LOOP itab INTO DATA(line) WHERE field NE `name`.
-   ...
- ENDLOOP.

2.4 TRY Statement¶

# should
TRY .
  ...
  CATCH.
    ...
ENDTRY.

常见转换异常

Exeception	Description
CX_SY_CONVERSION_CODEPAGE	System exception in character set conversion
CX_SY_CONVERSION_CODEPAGE_EX	System exception in character set conversion
CX_SY_CONVERSION_DATA_LOSS	Exception for Conversions Where Data Is Lost
CX_SY_CONVERSION_ERROR	System exception in conversion errors
CX_SY_CONVERSION_EXACT_NOT_SUP	Forbidden Type/Length Combination for MOVE EXACT
CX_SY_CONVERSION_INEXACT_FLTP	For Type F Only Integers of up to 15 Digits Allowed
CX_SY_CONVERSION_LOST_DECIMALS	Exception for Conversions with Loss of Decimal Places
CX_SY_CONVERSION_NO_BOOLEAN	System Exception for Conversion Error in xsd:boolean
CX_SY_CONVERSION_NO_DATE	System Exception when Changing a Date
CX_SY_CONVERSION_NO_DATE_TIME	System Exception for Data and Time Conversions
CX_SY_CONVERSION_NO_ENUM_VALUE	System exception in transformation of an enumeration val
CX_SY_CONVERSION_NO_NUMBER	System exception in transformation to a number
CX_SY_CONVERSION_NO_QNAME
CX_SY_CONVERSION_NO_RAW	System exception for overflow in conversion
CX_SY_CONVERSION_NO_TIME	System Exception when Changing a Time
CX_SY_CONVERSION_NO_UUID	System Exception for UUID Conversions
CX_SY_CONVERSION_OVERFLOW	System exception for overflow in conversion
CX_SY_CONVERSION_ROUNDING	Rounding Necessary
CX_SY_CONVERSION_SRC_TOO_SHORT	Source Data too short for MOVE EXACT
CX_SY_CONVERSION_UNKNOWN_CURR	Conversion error in currency unit
CX_SY_CONVERSION_UNKNOWN_LANGU	Conversion Error at Language Key
CX_SY_CONVERSION_UNKNOWN_UNIT	Conversion error in unit of measurement

2.5 INSERT Statement¶

+ INSERT VALUE #( char = value
+                 elem = me ) INTO TABLE char_tab.

- INSERT VALUE #( char = value elem = me ) INTO TABLE char_tab.

- INSERT VALUE #( char = value
-                 elem = me ) 
-   INTO TABLE char_tab.

2.6 CASE Statement¶

CASE option.

  WHEN A.
    ...

  WHEN B.
    ...

  WHEN C.
    ...

ENDCASE.

2.7 TYPES Statement¶

+ TYPES:
+   BEGIN OF t_point,
+     x TYPE i,
+     y TYPE i,
+   END OF t_point,
+   t_points TYPE STANDARD TABLE OF t_point WITH DEFAULT KEY.

- TYPES: BEGIN OF ts_fullpath,
-          title  TYPE string,
-          name   TYPE string,
-          ext    TYPE string,
-          path   TYPE string,
-          filter TYPE string,
-        END OF ts_fullpath.

2.8 SELECT Statement¶

SELECT SINGLE * 
  FROM ztable 
  INNER JOIN bkpf ON ztable~bukrs EQ bkpf~bukrs
                 AND ztable~belnr EQ bkpf~belnr
                 AND ztable~gjahr EQ bkpf~gjahr
  WHERE ztable~bukrs                 EQ gt_help_tab-bukrs
    AND ztable~hkont                 EQ gt_help_tab-hkont
    AND ztable~dekont_no             EQ u_out-dekont_no
    AND ztable~fiziksel_islem_tarihi EQ '01012018'
    AND ztable~gjahr                 EQ u_ut-year(4)
    AND ztable~stblg                 EQ ''
  INTO CORRESPONDING FIELDS OF ls_doc.

2.9 PERFORM Statement¶

PERFORM get_type 
  USING '1' '2' '3' 
  TABLES it_table 
  C lv_char.

3. References¶

最后更新: 2021-07-26
创建日期: 2021-03-04