Generic callbacks
- by bobobobo
Extends
So, I'm trying to learn template metaprogramming better and I figure this is a good exercise for it.
I'm trying to write code that can callback a function with any number of arguments I like passed to it.
// First function to call
int add( int x, int y ) ;
// Second function to call
double square( double x ) ;
// Third func to call
void go() ;
The callback creation code should look like:
// Write a callback object that
// will be executed after 42ms for "add"
Callback<int, int, int> c1 ;
c1.func = add ;
c1.args.push_back( 2 ); // these are the 2 args
c1.args.push_back( 5 ); // to pass to the "add" function
// when it is called
Callback<double, double> c2 ;
c2.func = square ;
c2.args.push_back( 52.2 ) ;
What I'm thinking is, using template metaprogramming I want to be able to declare callbacks like, write a struct like this (please keep in mind this is VERY PSEUDOcode)
<TEMPLATING ACTION <<ANY NUMBER OF TYPES GO HERE>> >
struct Callback
{
double execTime ; // when to execute
TYPE1 (*func)( TYPE2 a, TYPE3 b ) ;
void* argList ; // a stored list of arguments
// to plug in when it is time to call __func__
} ;
So for when called with
Callback<int, int, int> c1 ;
You would automatically get constructed for you by < HARDCORE TEMPLATING ACTION > a struct like
struct Callback
{
double execTime ; // when to execute
int (*func)( int a, int b ) ;
void* argList ; // this would still be void*,
// but I somehow need to remember
// the types of the args..
} ;
Any pointers in the right direction to get started on writing this?
