ABAP新语法中函数式调用的几种常见写法（to_upper, for, line_exists, xsdbool）

S/4HANA版本的NetWeaver平台上，ABAP已经进化的和现代编程语言很类似了。ABAP可以支持很多“函数式”调用的写法，这种写法让ABAP的写法更简短，也更容易被现代程序员所接受。

本文列举了最常见的几种“函数式”调用的写法，供大家参考。

"1. Variable in-line declaration
DATA(variable) = 'A'.   " MOVE 'A' TO variable.

"2. Use build-in function
DATA(uppercase) = to_upper( lowercase ).  " TRANSLATE lowercase TO UPPER CASE.

"3. += operation
index += 1.         " >= NW 7.54
index = index + 1.  " < NW 7.54
" ADD 1 TO index.

"4. Key word NEW to instantiate object
DATA(object) = NEW /clean/my_class( ).  " CREATE OBJECT object TYPE /dirty/my_class.

" 5. Key word FOR 
result = VALUE #( FOR row IN input ( row-text ) ).
" LOOP AT input INTO DATA(row).
"  INSERT row-text INTO TABLE result.
" ENDLOOP.

"6. READ TABLE
DATA(line) = value_pairs[ name = 'A' ].  " READ TABLE value_pairs INTO DATA(line) WITH KEY name = 'A'.

"7. xsdbool to do boolean expression
DATA(exists) = xsdbool( line_exists( value_pairs[ name = 'A' ] ) ).
IF line_exists( value_pairs[ name = 'A' ] ).
" READ TABLE value_pairs TRANSPORTING NO FIELDS WITH KEY name = 'A'.
" DATA(exists) = xsdbool( sy-subrc = 0 ).

欢迎大家补充、提问。