What does it do? The data roots used in an ST program can optionally be assigned type specifications. As a rule, types from the repository (ABAP Dictionary, types of global classes) are used, although separate type definitions can also be made in the ST program. An ST program outside of a template can contain one or more definitions of types with statement tt:type. The attribute name is used to declare a symbolic name that can be used to type data roots and in other type definitions. Elementary, structured, and tabular types can all be defined, which can be partially or completely generic. Moreover, references to globally defined data types of the repository and to types of the same ST program defined using tt:type are possible. Reference types cannot be defined as standalone types, but they can be created by using references to reference types from the ABAP repository.
Namespaces The following XML namespaces in asXML format must be used to specify types from the repository and from the same ST program:
http://www.sap.com/abapxml/types/type-pool/name describes the type pool name.
http://www.sap.com/abapxml/types/class-pool/class describes the global class class.
http://www.sap.com/abapxml/types/defined/name describes the type that is defined in the current ST program using tt:type. The type name that is specified in $[line-$]type then must have the form p:NAME, where the namespace prefix p must be bound to one of these URIs and NAME is the name of the actual type in uppercase letters. p therefore specifies where the type is defined.
Definition of Elementary Types For the definition of elementary types, the elementary ABAP types C , D, F, I, N, P, STRING, T, X or XSTRING (uppercase) are specified for the attribute value type after tt:type or tt:node. For types C, N, P, and X, the length can also be specified in the attribute length, and for type P the number of decimal places can be specified in attribute decimals . If decimals is specified without length, decimals is ignored. If length or decimals are not specified, the length and decimal places are generic. C without a length specification corresponds to the generic ABAP type csequence, that is, it includes c with any length and string. Similarly, xsequence applies to X. The name of an elementary type from the repository or the ST program can also be specified for the value of attribute type.
Definition of Structured Types The statement tt:node is used as an element of tt:type to define structured types. Here the name of a component is determined by the value of the attribute name and its type is determined using the value of the attribute $[line-$]type. A statement tt:node , which is an element of a different statement tt:node, defines a substructure. An element tt:type or tt:node that contains subelements tt:node must not specify any types except using $[line-$]type='?'. In this case, line-type='?' is used to define a tabular type with a structured line type. The type $[line-$]type can be specified after tt:node can be used to structure the types of a component as elementary types (see above), as table-like (see below), or as using a reference to a structured type of the repository or the ST program itself. The type of a component can be partly or completely generic. In addition, a structured type is generic by default in terms of the number and order of its components. This means that a data root that is typed with a structured type can be bound to an ABAP structure that contains the specified components in a different order and/or additional components. To define the number and order of the components of the initial part of a structured type or of the entire structured type without gaps, the corresponding component definitions tt:node can be specified as subelements of statement tt:front. Statement tt:type or tt:node may have exactly one tt:front statement as the first subelement. To restrict the number of components in a structure to the components that are defined in the ST program, the extensible attribute of statements tt:type or tt:node can be used. The following values can be specified for the attribute: ... 'on'$|'deep'$|'off'$|'deep-off' ... The value on states that the current element may have direct subelements that are not explicitly specified. The value deep states that the current element and its subelements can be enhanced and is the standard setting. The value off deactivates extensibility for the current element but not its subelements. In other words, direct subelements cannot be added to the element but its (specified) subelements can be. The value deep-off deactivates extensibility for the current element and its subelements. These settings can be overwritten locally in individual subelements.
Definition of Tabular Types The attribute line-type after tt:type or tt:node is used for the definition of tabular types. This attribute defines the type or the component as a table with the line type that is specified as the value of the attribute. Elementary types (see above) or any repository or ST program types can be specified as the line type. A structured line type can also be declared by specifying ? as the value of line-type. If the current element then contains tt:node statements as subelements, these define the components of the line type. The line type of a tabular type can be partly or completely generic. The latter is defined by specifying the type line-type='?' without defining components using tt:node.
Definition of Reference Types There is currently no ref-type addition available in tt:types for the definition of reference types. Standalone reference types can be created only by using a reference to a reference type in the ABAP repository. tt:parameter and tt:variable, however, do have a ref-type addition.
Definition of Generic Types All types whose properties have not been completely defined are generic in terms of the missing properties.
A type is completely generic if the attribute type is either not specified at all, or is specified with the value ?. Specifying type='?' is the same as not specifying anything. However, it should always be specified for reasons of readability. line-type='?' is also required to define a tabular type directly with a structured line type.
An elementary type N or P is partly generic if the length or decimal places are not specified for P.
Individual components can be generic in structured types and the number of components is also generic.
Tabular types can be partly or completely generic in terms of the line type.
ABAP_EXAMPLE_VX5 The type T1 that is defined in transformation DEMO_ST_NODE_TYPE below is a structure that contains at least component C, which is an internal table whose line type contains at least the components C1 (with dictionary type DDT1) and C2 (with defined type T2). Structure type T2 contains component D whose subcomponent D1 is an internal table with any line type. TRNS DEMO_ST_NODE_TYPE ABAP_EXAMPLE_END
