+Use %attribute when you have a pair of get/set methods to a +primitive type like: +
+ +
+%include "attribute.i"
+%attribute(A, int, a, get_a, set_a);
+
+struct A
+{
+ int get_a() const;
+ void set_a(int aa);
+};
+
++and you want to provide that variable as an attribute in the target +langage. This examples only works for primitive types, not derived +types. If you don't provide a 'set' method, a 'read-only' attribute +is generated, ie, like: +
+ ++%attribute(A, int, c, get_c); ++
+Use %attributeref when you have const/non-const reference +access methods for primitive types or class/structs, like: +
+ +
+%attributeref(A, int, b);
+
+struct A
+{
+ const int& b() const;
+ int& b();
+};
+
+%attributeref(B, int, c);
+
+struct B
+{
+ int& c();
+};
+
++You can also use +
+ ++%attributeref(Class, AttributeType, AttributeName, AccessorMethod) ++
+if the internal C++ reference methods have a different name from the +attribute you want, so +
+ ++%attributeref(B, int, d, c); ++
+is the same as the last example, but instead of the attribute 'c' being +called 'c', it is called 'd'. +
+ ++Now you can use the attributes like so: +
+ ++x = A() +x.a = 3 # calls A::set_a +print x.a # calls A::get_a + +x.b = 3 # calls A::b() +print x.b # calls A::b() const ++
+Use %attribute2 instead of %attribute to indicate +that reference-pointer translation is required. You +use %attribute2 instead of %attribute in cases like +this: +
+ +
+%attribute2(MyClass, MyFoo, Foo, GetFoo, SetFoo);
+%inline %{
+ struct MyFoo {
+ int x;
+ };
+ class MyClass {
+ MyFoo foo;
+ public:
+ MyFoo& GetFoo() { return foo; }
+ void SetFoo(const MyFoo& other) { foo = other; }
+ };
+%}
+
++Here, the data type of the property is a wrapped type (MyFoo) and on +the C++ side it is passed by reference. The problem is that the SWIG +wrapper will pass around a pointer (MyFoo *) which is not compatible +with the reference type of the accessors (MyFoo &). Therefore, if you +use %attribute, you'll get an error from your C/C++ +compiler. %attribute2 translates between a pointer and a +reference to eliminate the error. In case you're confused, let's make +it simple: just use %attribute at first, but if the C/C++ +compiler gives an error while compiling the wrapper, +try %attribute2 instead. +
+ +
+NOTE: remember that if the type contains commas, such as
+'std::pair