SAP NetWeaver AS ABAP Release 740, ©Copyright 2014 SAP AG. All rights reserved.
ABAP Keyword Documentation → ABAP − Release-Specific Changes → Changes in Releases 4.0 and 4.5 →
Extended Concept for Field Symbols in Release 4.0
The extended field symbol concept can be summarized as follows:
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: