Re: Help needed with walk_dir()
- Posted by DerekParnell (admin) Aug 04, 2010
- 1041 views
The routine_id is used as a sort of pointer-to-a-function...
... Having never learned C or lower-level stuff my understanding of pointers is hazy ...
You can think of routine ids as a kind of bookmark or place holder; its a way that you can call a routine when you don't know it's name.
In Euphoria, every routine is given a number when the application is run. You can find out what that number is by using the routine_id() function, and you can call the 'anonymous' routine by using it's number in the call_proc() or call_func() routine.
For example, the custom_sort function knows how to sort elements in a sequence but it doesn't know how to compare elements to work out which element should go before another element. Instead, it calls a routine that is written by you to get that information; but custom_sort does not know the name of your routine. So it calls your routine 'indirectly' using the call_func() routine with the routine id you initially passed to custom_sort().
