Dispatch table
In computer science, a dispatch table is a table of pointers to functions or methods. Use of such a table is a common technique when implementing late binding in object-oriented programming.Perl implementation
The following shows one way to implement a dispatch table in Perl, using a hash to store references to code.
- Define the table using one anonymous code-ref and one named code-ref
my %dispatch = ;
sub say_goodbye
- Fetch the code ref from the table, and invoke it
my $sub = $dispatch;
print $sub ? $sub-> : "unknown argument\n";
Running this Perl program as perl greet -h will produce "hello", and running it as perl greet -g will produce "goodbye".JavaScript implementation
Following is a demo of implementing dispatch table in JavaScript:
var thingsWeCanDo = ;
var doSomething = function
In object-oriented programming languages that support virtual methods, the compiler will automatically create a dispatch table for each object of a class containing virtual methods. This table is called a virtual method table or vtable, and every call to a virtual method is dispatched through the vtable.
