Downcast to c code#

The factory method of the following class returns a reference variable of the type of the class itself. These examples show how helper variables can be omitted by using the operator CAST.Ĭl_abap_classdescr=>describe_by_name( 'CL_ABAP_FORMAT' )Ĭl_abap_typedescr=>describe_by_name( 'T100' )Ĭl_abap_typedescr=>describe_by_name( 'SYST' )

To perform a down cast of a type description object to a specialized class. On the right and left of assignments with the assignment operator =. The constructor expressions can be used as Uses dereferencing operator and component selector in CAST with data types. Is checked using the predicate expression IS INSTANCE OF.

Downcast to c code#

The source code section below shows two equally valid down casts with the two possibleĬasting operators ?= and CAST. The constructor operator CONV is related to CAST, but performs a.WHEN TYPE of a case distinction using CASE TYPE OF. Down casts are also possible using the INTO addition of the statement.TYPE OF can be used to check whether a down cast can be applied to specific classes or interfaces. No empty parentheses can be specified after CAST.ĬAST works with an existing reference variable, which means that the result does not need to be saved to persist the referenced object.Explicit up casts with the casting operator CAST are suitable for declaring a more general type of a declared reference variable in.The casting operator CAST is suitable for avoiding the declaration of helper variables needed only for down casts.Type must be byte-like or character-like with the type c or string.Ĭan be appended (if the data type is suitable), except if the chaining uses the statement ASSIGN as aĪ LET expression let_exp can be specified (optional) before the argument to define local auxiliary fields. Type of the result must be convertible to the data type type with the following restriction: If the result is the result of a it can be specified as a writable expression in a.If a single expression points to one data object or component of a data object using precisely one following object component selector, ->, This makes it possible to test the feasibility of a down cast by catching the associated exception CX_SY_MOVE_CAST_ERROR.

Standalone method calls including chained method calls.Ī single expression not followed by the object component selector -> canīe specified as a standalone statement. ) can be specified using anįunctional positions.Furthermore, it is possible to introduce Like an object reference variable of the type class, a constructor expression CAST class(.) can be continued using aĭereferencing operator ->* if a structured type is used, it can be specified using an Like a data reference variable of type dtype, a constructor expression CAST dtype(.If type is more general than the static type of dobj, it is an explicit If the specified type type is more specific than the static type of dobj, it is aĭown cast. dobj is aĬasts of dobj to the specified type are performed in accordance with the same rules as apply to theĪssignments, ?=. If an object type is used, dobj must be an object reference variable. Type is specified, dobj must be a data reference variable. The parentheses must contain precisely one unnamed argument dobj. Can be specified only if the data type required in an operand position is unique and fully identifiable. any object type (class or interface) including the fully generic object type object.any non-generic data type dtype or the fully generic data type data.ABAP - Keyword Documentation →Ī constructor expression with the casting operator CAST performs aĭobj and creates a reference variable of the static type type as a result. SAP NetWeaver AS ABAP Release 750, ©Copyright 2016 SAP AG.