1.ABAP Reference

ABAP是SAP开发的用来在SAP环境构建复杂应用。三层结构：表示层，用户使用GUI,Web Browser；应用层，许多应用服务器组成，应用服务器为应用执行环境；数据层，数据库组成。

这三层通信组件：ICM(Internet Communication Manager)网络通信管理器提供网络通信，例如：Web Dynpro，BSP；RFC Interface,同一服务器，不同服务器直接调用RFC Function。

SAP支持Unioncode和Non-Unioncode系统。Non-Unioncode表示一个字符使用一个字节，Unioncode，万国码，对所有语言字符进行统一唯一的编码，utf-8占1到4个字节,utf-16占2到4个字节,utf-32占4个字节。

在Unioncode之前，SAP使用ASCII，EBCDIC等只用一个字节表示字符，SJIS，BIG5等使用两个字节表示字符。

使用Tcode:UCCHECK,检查非Unioncode Program是否能够转换为Unioncode Program。

1.1 ABAP 关键字

使用Tcode:ABAPDOCU,打开ABAP帮助文档，ABAP Words，可以查看ABAP的所有关键字。

关键字，操作数，操作符。

示例1：

"ABAP 关键字，操作数，操作符
FORM f_abap_statement.
  "结构体操作数-
  DATA:BEGIN OF struc1,
        elem1 TYPE char1,
     END OF struc1.
  "通过-访问结构体下element
  struc1-elem1 = 'X'.
  "对象操作数->
  DATA: lo_c1 TYPE REF TO c1.
  CREATE OBJECT lo_c1.
  lo_c1->method1( ).
  "静态对象操作数=>
  c1=>method2( ).
  "接口操作数~
  lo_c1->i1~imethod1( ).

  "使用关键字,在前面加上！
  DATA !type TYPE char1.
  !type = 'X'.
  MESSAGE !type TYPE 'S'.

  "操作符
  "1.赋值操作符, =,?=
  "MOVE {source {TO|?TO} destination}
  " | {EXACT source TO destination}.
  DATA:num1 TYPE char10 VALUE '1234567890'.
  DATA:num2 TYPE char5.
  "自动截断长度
  MOVE num1 TO num2.
  num2 = num1.
  "使用EXACT,当精度丢失时，抛异常
  "MOVE EXACT num1 TO num2.
  "?=,MOVE ?TO只能用于对象
  "MOVE num1 ?TO num2.
  WRITE:/ num1,num2.

  "2.算术操作符
  "+|-|*|/|DIV|MOD|**
  DATA:cal_num1 TYPE I.
  DATA:cal_num2 TYPE float.
  cal_num1 = 10.
  cal_num2 = '3.0'.
*  cal_num2 = cal_num1 + cal_num2.
*  WRITE:/ cal_num1,cal_num2.
*  cal_num2 = cal_num1 - cal_num2.
*  WRITE:/ cal_num1,cal_num2.
*  cal_num2 = cal_num1 * cal_num2.
*  WRITE:/ cal_num1,cal_num2.
  cal_num2 = cal_num1 / cal_num2.
  WRITE:/ cal_num1,cal_num2.
  "整除
  cal_num2 = cal_num1 DIV cal_num2.
  WRITE:/ cal_num1,cal_num2.
  "幂运算
*  cal_num2 = cal_num1 ** cal_num2.
*  WRITE:/ cal_num1,cal_num2.
  "取余
*  cal_num2 = cal_num1 MOD cal_num2.
*  WRITE:/ cal_num1,cal_num2.

  "3.位运算
  "BIT-NOT,BIT-AND,BIT-OR,BIT-XOR
  DATA:bit_num1 TYPE x VALUE 'E0'.
  DATA:bit_num2 TYPE x VALUE '0E'.
  DATA:bit_num3 TYPE x.
  bit_num3 = BIT-NOT bit_num1.
  WRITE:/ bit_num3.
  bit_num3 = bit_num1 BIT-AND bit_num2.
  WRITE:/ bit_num3.
  bit_num3 = bit_num1 BIT-OR bit_num2.
  WRITE:/ bit_num3.
  bit_num3 = bit_num1 BIT-XOR bit_num2.
  WRITE:/ bit_num3.

  "4.字符串运算
  "&
  DATA:str_num1 TYPE char1 VALUE '1'.
  DATA:str_num2 TYPE string VALUE 'string'.
  DATA:str_num3 TYPE char20.
  str_num3 = str_num1 && str_num2.
  WRITE:/ str_num3.

  "5.比较运算
  "= EQ,<> >< NE,< LT,<= LE,> GT,>= GE
  "字符类型数据比较关系
  "CO Contains only, op1 CO op2,op1仅包含op2中字符.
  "大小写敏感,末尾空格
  DATA:co_num1 TYPE C LENGTH 10 VALUE 'abcde'.
  DATA:co_num2 TYPE C LENGTH 5 VALUE 'abc'.
  IF co_num1 CO co_num2.
    "如果true,sy-fdpos值为op1的长度,定义的长度10
    WRITE:/ 'true:',sy-fdpos.
  ELSE.
    "如果false,sy-fdpos的值为op1第一个不匹配字符偏移量
    WRITE:/ 'fasle:',sy-fdpos.
  ENDIF.
  "CN Contains not only,和CO相反,op1 CN op2,op1不仅包号op2中字符
  "true,sy-fdpos为op1第一个不匹配字符偏移量，false,sy-fdpos返回op1长度

  "CA Contains Any,op1 CA op2,op1 包含任意op2中字符
  "大小写敏感,末尾空格
  DATA:ca_num1 TYPE C LENGTH 10 VALUE 'abc'.
  DATA:ca_num2 TYPE C LENGTH 5 VALUE 'cde'.
  IF ca_num1 CA ca_num2.
    "如果true,sy-fdpos的值为op1第一个匹配字符偏移量
    WRITE:/ 'true:',sy-fdpos.
  ELSE.
    "如果false,sy-fdpos的值为op1长度
    WRITE:/ 'fasle:',sy-fdpos.
  ENDIF.
  "NA Contains not Any,op1 NA op2,op1不包含任意op2字符
  "如果false,sy-fdpos的值为op1第一个匹配字符偏移量
  "如果true,sy-fdpos的值为op1长度

  "CS Contains string,op1 CS op2,op1包含op2
  "大小写不敏感，头部空格会比较
  DATA:cs_num1 TYPE C LENGTH 10 VALUE 'abc'.
  DATA:cs_num2 TYPE C LENGTH 5 VALUE 'ab'.
  IF cs_num1 CS cs_num2.
    "如果true,sy-fdpos的值为op1第一个开始匹配字符偏移量
    WRITE:/ 'true:',sy-fdpos.
  ELSE.
    "如果false,sy-fdpos的值为op1长度
    WRITE:/ 'fasle:',sy-fdpos.
  ENDIF.
  "NS Contains No string,op1 NS op2,op1不包含op2
  "如果true,sy-fdpos的值为op1长度
  "如果false,sy-fdpos的值为op1第一个开始匹配字符偏移量

  "CP Cover Pattern，op1 CP op2,op1匹配op2
  "使用*匹配字符串，+匹配任意单个字符
  "大小写不敏感
  DATA:cp_num1 TYPE C LENGTH 10 VALUE 'deabc'.
  DATA:cp_num2 TYPE C LENGTH 8 VALUE '*abc*'.
  IF cp_num1 CP cp_num2.
    "sy-fdpos contains the offset of operand2 in operand1
    WRITE:/ 'true:',sy-fdpos.
  ELSE.
    "如果false,sy-fdpos的值为op1长度
    WRITE:/ 'fasle:',sy-fdpos.
  ENDIF.
  "NP NO Pattern,op1 NP op2,op1不匹配op2

  "字节数据类型关系比较，只支持xstring类型
  "BYTE-CO,op1 BYTE-CO op2,op1 contains bytes only out of op2.
  "BYTE-CN,op1 contains bytes not only out of op2
  "BYTE-CA,op1 contains any bytes out of op2
  "BYTE-NA,op2 contains not any bytes out of op2
  "BYTE-CS,op1 包含 op2
  "BYTE-NS,op1 不包含op2
  DATA:bco_num1 TYPE xstring.
  DATA:bco_num2 TYPE xstring.
  bco_num1 = '0811FE11'. "8011FE11都false,偏移量为0
  bco_num2 = '0022FE11'.
  IF bco_num1 BYTE-CO bco_num2.
    "返回op1 length4,每两个字符占一个长度
    WRITE:/ 'true:',sy-fdpos.
  ELSE.
    "false,返回op1,第一个不匹配字节偏移量
    WRITE:/ 'fasle:',sy-fdpos.
  ENDIF.

  "Bit关系比较,只支持x,xstring类型
  "O,Z,M
  DATA:b_num1 TYPE xstring VALUE '1111'.
  DATA:b_num2 TYPE xstring VALUE 'FFFF'.
  "Ones: True if the bits that are 1 in operand2, are also 1 in operand1. 
  "If operand2 contains only zeroes, the logical expression is always true.
  IF bit_num1 O bit_num2.
    WRITE:/ 'true'.
  ELSE.
    WRITE:/ 'false'.
  ENDIF.
  "Zeros: True, if the bits that are 1 in operand2 are 0 in operand1. 
  "If operand2 contains only zeroes, the logical expression is always true.
  IF bit_num1 Z bit_num2.
    WRITE:/ 'true'.
  ELSE.
    WRITE:/ 'false'.
  ENDIF.
  "Mixed: True, if of the bits that are 1 in operand2, at least one is 1 and one is 0 in operand1. 
  "If operand2 contains only zeroes, the logical expression is always false.
  IF bit_num1 M bit_num2.
    WRITE:/ 'true'.
  ELSE.
    WRITE:/ 'false'.
  ENDIF.

  "布尔操作运算符
  "AND,OR,NOT,EQUIV
  
  "文字运算符
  "'...' & '...' & ... & '...' `...` & `...` & ... & `...` 
  DATA:literal_num1 TYPE C LENGTH 10.
  DATA:literal_num2 TYPE C LENGTH 20.
  "只能运算字符，不能是变量
  literal_num1 = 'he' & 'll' & 'o'.
  "literal_num2 = literal_num1 & literal_num1.
ENDFORM.