Function pointer as non-type template parameter
I'm currently porting GTK+ to a dynamic language, one of the challenge is to convert GTK+ functions to language bindings. I attempt to use C++ templates to simplify it.
For example, to convert 'gtk_widget_show_all' to dynamic language's 'show_all', I first define following generic function:
template<class Type, class GtkType, void function (GtkType*)>
static Handle<Value> SimpleMethod (const Arguments& args) {
GtkType *obj = blablabla...;
function (obj);
return Undefined ();
}
Then I can bind the 'gtk_widget_show_all' to 'show_all' very easily:
NODE_SET_PROTOTYPE_METHOD (constructor_template, "show_all", (SimpleMethod<Widget, GtkWidget, gtk_widget_show_all>));
But when the GTK+ function becomes more complex, It would be a hell for defining every SimpleMethod for every type of GTK+ function, like this:
template<class Type, class GtkType, void function (GtkType*, const char *)>
static Handle<Value> SimpleMethod (con开发者_高级运维st Arguments& args) {
...
}
template<class Type, class GtkType, void function (GtkType*, int)>
static Handle<Value> SimpleMethod (const Arguments& args) {
...
}
template<class Type, class GtkType, int function (GtkType*)>
static Handle<Value> SimpleMethod (const Arguments& args) {
...
}
template<class Type, class GtkType, void function (GtkType*, const char *, const char *)>
static Handle<Value> SimpleMethod (const Arguments& args) {
...
}
It will become rather disgusting. Is there a good way to simplify those functions to one function?
You can define a number of overloads, based on the number of arguments, like this:
template<class Type, class GtkType, class ReturnType, ReturnType function ()>
static Handle<Value> SimpleMethod (const Arguments& args) {
...
}
template<class Type, class GtkType, class ReturnType, class Arg0, ReturnType function( Arg0 )>
static Handle<Value> SimpleMethod (const Arguments& args) {
...
}
...and so on...
Boost.Preprocessor would help you generate the overloads. C++11 variadic template arguments should make this much easier.
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