ABAP Keyword Documentation →  ABAP − Reference →  Processing Internal Data →  Assignments →  Assigning References →  Setting Field Symbols →  ASSIGN → 

ASSIGN - casting_spec

Short Reference

Syntax

... { }
  | { CASTING { { }
             | {TYPE type|(name)}
              | {LIKE dobj}
              | {[TYPE p] DECIMALS dec}
              | {TYPE HANDLE handle} } }
  | { obsolete_casting } ... .

Alternatives:

1. ... { }

2. ... CASTING ...

Effect

The casting_spec specification determines with the data type that handles the memory area mem_area assigned to the field symbol if a statement contains the field symbol at an operand position. Either the addition CASTING can be specified or nothing at all. Outside of classes, the obsolete variants obsolete_casting are also possible.

In assignments of table expressions, the first alternative can be used without further additions.

Alternative 1

... { }


Effect

If nothing is specified for casting_spec, the field symbol is given the data type of the data object used in mem_area and the assigned memory area is handled accordingly. This data type must match the typing of the field symbol.

Alternative 2

... CASTING ...


Extras:

1. ... { }

2. ... TYPE type|(name)

3. ... LIKE dobj

4. ... [TYPE p] DECIMALS dec

5. ... TYPE HANDLE handle

Effect

If you use the addition CASTING in casting_spec, the memory area is handled as if it had the type specified by CASTING. When specifying CASTING, the field symbol must not be typed with the obsolete STRUCTURE addition of the FIELD SYMBOLS statement.

Casting can either take place implicitly using the typing of the field symbol or explicitly using one of the additions TYPE, LIKE, or DECIMALS. In explicit castings, the field symbol cannot be specified in full; instead it must be specified generically.

Notes

Addition 1

... { }

Effect

If the CASTING addition is specified without any further additions, the assigned memory area is cast to the type of the field symbol. The field symbol must be either fully typed, or typed with one of the generic predefined ABAP types c, n, p, or x.

Addition 2

... TYPE type|(name)

Effect

After TYPE, a data type type can be specified directly, or a character-like data object name in parentheses, which must contain the name of a data object in uppercase when the statement is executed. The assigned memory area is cast to the specified type. The data type specified after TYPE cannot be generic. The exceptions to this rule are the predefined ABAP types c, n, p and x. However, table categories cannot be specified, nor REF TO.

The field symbol <fs> can only be typed generically and not in full. The specified data type has to match the generic typing of the field symbol, meaning that castings are allowed to specialize the generic typing but not to make more general.

If a generic character-like type c or n is specified after TYPE, the length of the assigned memory area must be a multiple of the length of a character in the memory when the statement is executed in Unicode programs.

Example

In the following example, one of the two ASSIGN statements produces a runtime error, since the alignment requirement for the type c is not met. Which of the statements produces the runtime error is not generally defined and depends on the preceding declarations.

DATA hex        TYPE x LENGTH 10.

FIELD-SYMBOLS <fs> TYPE any.

ASSIGN hex+0(4) TO <fs> CASTING type c.
ASSIGN hex+1(4) TO <fs> CASTING type c.

Addition 3

... LIKE dobj

Effect

The following can be specified after LIKE:

The field symbol <fs> can only be typed generically and not in full. The specified data type has to match the generic typing of the field symbol, meaning that castings are allowed to specialize the generic typing but not to make more general.

Notes

Addition 4

... [TYPE p] DECIMALS dec

Effect

A numeric data object dec must be specified after DECIMALS. The assigned memory area is cast to the data type p, whereby the number of decimal places is determined by the content of dec. The number of decimal places must not exceed the number of decimal digits. TYPE does not need to be specified for DECIMALS. If TYPE is used, only the data type p (which is used anyway) can be specified.

The field symbol <fs> can only be typed generically and not in full. The specified data type has to match the generic typing of the field symbol, meaning that castings are allowed to specialize the generic typing but not to make more general.

Example

Calculating the quotient from the packed number pack and the field symbol <pack> demonstrates the effect of casting with the addition DECIMALS. Factors between 10 and 100,000,000 are determined. When using <pack> in operand positions, a different value is used than when using pack.

DATA output TYPE TABLE OF string WITH EMPTY KEY.
DATA pack   TYPE p LENGTH 8 DECIMALS 0 VALUE '12345678'.
FIELD-SYMBOLS <pack> TYPE p.

DO 8 TIMES.
  ASSIGN pack TO <pack> CASTING DECIMALS sy-index.
  APPEND CONV string( pack / <pack> ) TO output.
ENDDO.
cl_demo_output=>display( output ).

Addition 5

... TYPE HANDLE handle

Effect

After TYPE HANDLE, a reference variable handle of the static type of the CL_ABAP_DATADESCR class or its subclasses is specified and it points to a type description object of the RTTS. The assigned memory area is cast to the type described by the type description object.

The field symbol <fs> can only be typed generically and not in full. The specified data type has to match the generic typing of the field symbol, meaning that castings are allowed to specialize the generic typing but not to make more general.

The addition CASTING TYPE HANDLE cannot be used with the addition RANGE.

Note

The type description object object may have been created using the RTTS methods on existing data objects, or using the definition of a new data type.






Continue
Casting Examples