Specifying Types
----------------
.. _typesystem:
typesystem
^^^^^^^^^^
This is the root node containing all the type system information. It can
have a number of attributes, described below.
.. code-block:: xml
The **package** attribute is a string describing the package to be used,
e.g. "QtCore".
The *optional* **default-superclass** attribute is the canonical C++ base class
name of all objects, e.g., "object".
load-typesystem
^^^^^^^^^^^^^^^
The load-typesystem node specifies which type systems to load when mapping
multiple libraries to another language or basing one library on another, and
it is a child of the typesystem node.
.. code-block:: xml
The **name** attribute is the filename of the typesystem to load, the
**generate** attribute specifies whether code should be generated or not. The
later must be specified when basing one library on another, making the generator
able to understand inheritance hierarchies, primitive mapping, parameter types
in functions, etc.
Most libraries will be based on both the QtCore and QtGui modules, in which
case code generation for these libraries will be disabled.
rejection
^^^^^^^^^
The rejection node rejects the given class, or the specified function or
field, and it is a child of the typesystem node.
.. code-block:: xml
The **class** attribute is the C++ class name of the class to reject. Use the
*optional* **function-name** or **field-name** attributes to reject a particular
function or field. Note that the **field-name** and **function-name** cannot
be specified at the same time. To remove all occurrences of a given field or
function, set the class attribute to \*.
.. _primitive-type:
primitive-type
^^^^^^^^^^^^^^
The primitive-type node describes how a primitive type is mapped from C++ to
the target language, and is a child of the typesystem node. Note that most
primitives are already specified in the QtCore typesystem.
.. code-block:: xml
The **name** attribute is the name of the primitive in C++, the optional,
**target-name** attribute is the name of the primitive type in the target
language. If the later two attributes are not specified their default value
will be the same as the **name** attribute.
The *optional* **since** value is used to specify the API version of this type.
If the *optional* **preferred-conversion** attribute is set to *no*, it
indicates that this version of the primitive type is not the preferred C++
equivalent of the target language type. For example, in Python both "qint64"
and "long long" become "long" but we should prefer the "qint64" version. For
this reason we mark "long long" with preferred-conversion="no".
The *optional* **preferred-conversion** attribute tells how to build a default
instance of the primitive type. It should be a constructor call capable of
creating a instance of the primitive type. Example: a class "Foo" could have
a **preferred-conversion** value set to "Foo()". Usually this attribute is
used only for classes declared as primitive types and not for primitive C++
types, but that depends on the application using *ApiExtractor*.
.. _namespace:
namespace-type
^^^^^^^^^^^^^^
The namespace-type node maps the given C++ namespace to the target language,
and it is a child of the typesystem node. Note that within namespaces, the
generator only supports enums (i.e., no functions or classes).
.. code-block:: xml
The **name** attribute is the name of the namespace, e.g., "Qt". The **package**
attribute can be used to override the package of the type system.
The *optional* **since** value is used to specify the API version of this type.
enum-type
^^^^^^^^^
The enum-type node maps the given enum from C++ to the target language,
and it is a child of the typesystem node. Use the reject-enum-value to
reject values.
.. code-block:: xml
The **name** attribute is the fully qualified C++ name of the enum
(e.g.,"Qt::FillRule"). If the *optional* **flags** attribute is set to *yes*
(the default is *no*), the generator will expect an existing QFlags for the
given enum type. The **lower-bound** and **upper-bound** attributes are used
to specify runtime bounds checking for the enum value. The value must be a
compilable target language statement, such as "QGradient.Spread.PadSpread"
(taking again Python as an example). If the **force-integer** attribute is
set to *yes* (the default is *no*), the generated target language code will
use the target language integers instead of enums. And finally, the
**extensible** attribute specifies whether the given enum can be extended
with user values (the default is *no*).
The *optional* **since** value is used to specify the API version of this type.
The attribute **identified-by-value** helps to specify anonymous enums using the
name of one of their values, which is unique for the anonymous enum scope.
Notice that the **enum-type** tag can either have **name** or **identified-by-value**
but not both.
reject-enum-value
^^^^^^^^^^^^^^^^^
The reject-enum-value node rejects the enum value specified by the **name**
attribute, and it is a child of the enum-type node.
.. code-block:: xml
This node is used when a C++ enum implementation has several identical numeric
values, some of which are typically obsolete.
.. _value-type:
value-type
^^^^^^^^^^
The value-type node indicates that the given C++ type is mapped onto the target
language as a value type. This means that it is an object passed by value on C++,
i.e. it is stored in the function call stack. It is a child of the :ref:`typesystem` node.
.. code-block:: xml
The **name** attribute is the fully qualified C++ class name, such as
"QMatrix" or "QPainterPath::Element". The **copyable** attribute is used to
force or not specify if this type is copyable. The *optional* **hash-function**
attribute informs the function name of a hash function for the type.
The *optional* attribute **stream** specifies whether this type will be able to
use externally defined operators, like QDataStream << and >>. If equals to **yes**,
these operators will be called as normal methods within the current class.
The *optional* **since** value is used to specify the API version of this type.
.. _object-type:
object-type
^^^^^^^^^^^
The object-type node indicates that the given C++ type is mapped onto the target
language as an object type. This means that it is an object passed by pointer on
C++ and it is stored on the heap. It is a child of the :ref:`typesystem` node.
.. code-block:: xml
The **name** attribute is the fully qualified C++ class name. If there is no
C++ base class, the default-superclass attribute can be used to specify a
superclass for the given type, in the generated target language API. The
**copyable** and **hash-function** attributes are the same as described for
:ref:`value-type`.
The *optional* attribute **stream** specifies whether this type will be able to
use externally defined operators, like QDataStream << and >>. If equals to **yes**,
these operators will be called as normal methods within the current class.
The *optional* **since** value is used to specify the API version of this type.
interface-type
^^^^^^^^^^^^^^
The interface-type node indicates that the given class is replaced by an
interface pattern when mapping from C++ to the target language. Using the
interface-type node implicitly makes the given type an :ref:`object-type`.
.. code-block:: xml
The **name** attribute is the fully qualified C++ class name. The *optional*
**package** attribute can be used to override the package of the type system.
If there is no C++ base class, the *optional* **default-superclass** attribute
can be used to specify a superclass in the generated target language API, for
the given class.
The *optional* **since** value is used to specify the API version of this interface.
.. _container-type:
container-type
^^^^^^^^^^^^^^
The container-type node indicates that the given class is a container and
must be handled using one of the conversion helpers provided by attribute **type**.
.. code-block:: xml
The **name** attribute is the fully qualified C++ class name. The **type**
attribute is used to indicate what conversion rule will be applied to the
container. It can be: *list*, *string-list*, *linked-list*, *vector*, *stack*,
*queue*, *set*, *map*, *multi-map*, *hash*, *multi-hash* or *pair*.
The *optional* **since** value is used to specify the API version of this container.
.. _function:
function
^^^^^^^^
The function node indicates that the given C++ global function is mapped onto
the target language.
.. code-block:: xml
This tag has some limitations, it doesn't support function modifications, besides you
can't add a function overload using :ref:`add-function` tag to an existent function.
These limitation will be addressed in future versions of ApiExtractor.
The *optional* **since** value is used to specify the API version of this function.