ABAP Keyword Documentation → ABAP − Reference → Obsolete Language Elements → Obsolete Program Flow → Obsolete Control Structures
DO - VARYING
Other versions: 7.31 | 7.40 | 7.54
Obsolete Syntax
DO ... VARYING dobj FROM dobj1 NEXT dobj2 [RANGE range]
[VARYING ...].
[statement_block]
ENDDO.
Effect
The addition VARYING
assigns a new value to a variable dobj
for each pass of a DO
loop. It can be used more than once in a DO
statement.
dobj1
and dobj2
are the first two data objects
in a string of data objects that are the same distance apart in the memory. The data types of
dobj, dobj1
, and dobj2
must be flat and
compatible with each other. dobj1
and dobj2
must
be parts of a flat data object. These parts must be either structure components of the same structure or subareas of the same data object specified using offsets/lengths.
In the first pass of the loop, the content of the data object dobj1
is assigned
to dobj
, and in the second loop, the content of the data object dobj2
is assigned. In the subsequent loops, dobj
is assigned the content of the
data object that is the same distance in the memory from the previously assigned data object, as dobj2
is from dobj1
. There is no type conversion.
If the processing block
is exited correctly using ENDDO
,
CHECK, or EXIT
, the
content of the variable dobj
at the end of the loop pass is assigned to the
previously assigned data object dobj1
or dobj2
without conversion. If it is exited using another statement, such as
RETURN or RAISE EXCEPTION
, no conversion takes place.
The addition RANGE
defines the memory area that can be processed using the
addition VARYING
. After RANGE
, an elementary data
object range
of type c
, n
,
or x
, or a structure can be specified. The memory area of range
must include the ranges of dobj1
and dobj2
. In
deep structures, the deep components
are exceptions to the permitted area. The DO
loop must be ended before non-permitted
memory areas are accessed, namely areas outside of range
or their deep components. If not, a non-handleable exception is raised.
The addition RANGE
can be omitted only if it is known statically that
dobj1 and dobj2
are components from the same structure. The permitted
memory area is then determined from the smallest substructure that contains dobj1
and dobj2
.
Notes
-
The way the addition
VARYING
works depends on the internal layout of the working memory, which itself can be affected by alignment gaps. -
Instead of the addition
VARYING
, the statement ASSIGN should be used in the loop with the additionINCREMENT
.
Example
In the first DO
loop, subareas of the data object text
are edited using offset/length access. The addition RANGE
must be specified
here. In the second DO
loop, the program accesses the components of the data
object text
. In this case, it is not necessary to specify RANGE
.
The third DO
loop shows how the functions of the second loop can be programmed
using the statement ASSIGN INCREMENT
.
DATA: BEGIN OF text,
word1 TYPE c LENGTH 4 VALUE 'AAAA',
word2 TYPE c LENGTH 4 VALUE 'BBBB',
word3 TYPE c LENGTH 4 VALUE 'CCCC',
word4 TYPE c LENGTH 4 VALUE 'DDDD',
END OF text.
DATA: word TYPE c LENGTH 4,
char1 TYPE c LENGTH 1,
char2 TYPE c LENGTH 1,
leng TYPE i.
FIELD-SYMBOLS <word> LIKE text-word1.
DATA inc TYPE i.
DESCRIBE FIELD text LENGTH leng IN CHARACTER MODE.
leng /= 2.
cl_demo_output=>begin_section( `First Loop` ).
DO leng TIMES VARYING char1 FROM text(1)
NEXT text+2(1) RANGE text
VARYING char2 FROM text+1(1)
NEXT text+3(1) RANGE text.
cl_demo_output=>write( |{ char1 } { char2 }| ).
char1 = 'x'.
char2 = 'y'.
ENDDO.
cl_demo_output=>next_section( `Second Loop` ).
DO 4 TIMES VARYING word FROM text-word1 NEXT text-word2.
cl_demo_output=>write( word ).
ENDDO.
cl_demo_output=>next_section( `Third Loop` ).
DO.
inc = sy-index - 1.
ASSIGN text-word1 INCREMENT inc TO <word> RANGE text.
IF sy-subrc = 0.
cl_demo_output=>write( <word> ).
ELSE.
EXIT.
ENDIF.
ENDDO.
cl_demo_output=>display( ).
Exceptions
Non-Handleable Exceptions
-
Cause: Invalid access to
deep components within the area specified by the
RANGE
-addition.
Runtime error:DO_WHILE_VARY_ILLEGAL_ACCESS
-
Cause: Access to data outside the range specified by the
RANGE
addition.
Runtime error:DO_WHILE_VARY_NOT_IN_RANGE