SAP NEWS-40-ASSIGN documentation, setup help and example usage

ARTICLE

Extended Concept for Field Symbols in Release 4.0

The extended field symbol concept can be summarized as follows:

The behavior of typed and untyped field symbols

has been standardized.

New predicate expression fs IS ASSIGNED

New statement UNASSIGN fs

Like typed field symbols, untyped field symbols are now, by default, not assigned. This means that a write access in either case (like
fs = f. ) produces a runtime error.
At the same time, read access to typed unassigned field symbols is also not possible.
Read access to untyped, unassigned field symbols is only allowed for the sake of compatibility (default value SPACE ).
Unassigned field symbols, however, should no longer be accessed.
The new predicate expression fs IS ASSIGNED can be used to query whether a field has already been assigned to the field symbol fs .
The new statement UNASSIGN fs sets the field symbol <(><<)>fs> so that it is not pointing to a field.

The expression IS ASSIGNED , and the ASSIGN and UNASSIGN
statements enable the state of a field symbol to be established and modified at any time. This makes ABAP programs simpler and less error-prone.

Further changes:

Dynamic ASSIGN ( ASSIGN (f) TO fs . ):

If fs is an untyped field symbol and the contents of
f are invalid, ,the field symbol is not set.

ASSIGN with offset and length for VALUE parameters in

FORMS and FUNCTIONS :
A runtime error is produced if ASSIGN f+off(len) TO fs is used to address areas beyond the range of the VALUE parameter f .

Non-assigned field symbols in INSERT , SORT , and AT :

If the field symbol <(><<)>fs> was not yet assigned (using ASSIGN ), it is ignored in the following statements:
INSERT fs INTO fg.
SORT BY fs .
SORT itab BY fs .
AT NEW fs .
AT END OF fs .