Changes between Version 1 and Version 2 of code/doc/Functor

Timestamp:

Sep 30, 2008, 12:30:30 AM (17 years ago)

Author:

landauf

Comment:

—

code/doc/Functor

@@ -67 +67 @@
 
 == Types ==
+There are two types of Functors: Functors for static functions and Functors for member functions. The following sections explain the difference.
+
 === FunctorStatic ===
+C++ knows two types of static functions:
+
+Static functions in a class:
+{{{
+class SomeClass
+{
+    static void someFunction();
+};
+}}}
+And C functions outside of a class:
+{{{
+void someOtherFunction();
+}}}
+
+Both types are covered by FunctorStatic. FunctorStatic is in fact just a Functor, but you can use it to force static functions:
+{{{
+class SomeClass
+{
+    static void staticFunction();
+    void nonstaticFunction();
+};
+
+FunctorStatic* functor1 = createFunctor(&SomeClass::staticFunction);    // this works
+FunctorStatic* functor2 = createFunctor(&SomeClass::nonstaticFunction); // this fails
+}}}
+However, this would work:
+{{{
+Functor* functor2 = createFunctor(&SomeClass::nonstaticFunction);
+}}}
 
 === FunctorMember ===
+There are two types of member functions: constant and non-constant.
+{{{
+class SomeClass
+{
+    void constFunction() const;
+    void nonconstFunction();
+};
+}}}
 
-== Template ==
+Both types are covered by FunctorMember, but in some cases you have to be aware of the intern difference.
+
+FunctorMember is in fact just a Functor, but it needs an object to call the function. Just pass the object in front of the arguments when calling the function:
+{{{
+class SomeClass
+{
+    void someFunction(int value);
+};
+
+SomeClass* object = new SomeClass();
+FunctorMember* functor = createFunctor(&SomeClass::someFunction);
+
+(*functor)(object, 10); // this is equivalent to object->someFunction(10);
+}}}
+
+You can bind an object to a Functor by adding the object with '''setObject('''''object''''')'''. If an object is bound to a Functor, you can call the functor without passing the object again:
+{{{
+class SomeClass
+{
+    void someFunction(int value);
+};
+
+SomeClass* object = new SomeClass();
+FunctorMember* functor = createFunctor(&SomeClass::someFunction);
+
+function->setObject(object); // binds object to the Functor
+
+(*functor)(10); // this is equivalent to object->someFunction(10);
+}}}
+
+Note: If you add a constant object, you can only call the Functor if the assigned function-pointer leads to a constant function too.
+
+== Template and ambiguity ==
 
 == Examples ==