What is the difference between -> and :: in Perl

Question

What is the exact difference between :: and -> in Perl?

-> sometimes works where :: does not.

Answer 1

When the right hand side is a function -> passes its left hand side as the first argument to the function. So the following examples are equivalent if $foo is an object blessed to package Foo and Bar is in package Foo. -> will resolve inherited methods making it cleaner and more useful for objects.

$foo->Bar();

Foo::Bar($foo);

-> can also take a package name

Foo->Bar();

Foo::Bar('Foo');

This means that -> is generally used in instance methods so that the object is passed its self and constructors so the constructors know which package to bless with. This is usually a parameter so it can be inherited.