How to create a reference to a subroutine in Perl?
A reference to an anonymous subroutine can be created by using sub without a subname as follows − Dereferencing returns the value from a reference point to the location. To dereference a reference simply use $, @ or % as prefix of the reference variable depending on whether the reference is pointing to a scalar, array, or hash.
Why do we use the ref extension in Perl?
We use the _ref extension so it will stand out for us that we expect to have a reference in that scalar. This is not a requirement and Perl does not care, but it might be useful while learning about them. If we now call print $names_ref; we’ll see the following:
When do you use the word reference in Perl?
When the word “reference” is used without an adjective, as in the following paragraph, it is usually talking about a hard reference. References are easy to use in Perl. There is just one overriding principle: in general, Perl does no implicit referencing or dereferencing.
How to de reference two arrays in Perl?
If you call add (@first, @second), on the receiving end the two arrays will be flattened together into @_ and you won’t be able to tell them apart. Better to pass two reference like this: add (\\@first, \\@second) and then de-reference them inside the function:
What kind of data type is a Perl reference?
A Perl reference is a scalar data type that holds the location of another value which could be scalar, arrays, or hashes.
Why do you need prototype for Debug in Perl?
Because the ($;$) prototype tells perl “debug is a function that can take one or two arguments, each with scalar context imposed on the call site”. The bit about context is where people usually get tripped up, because then if you try to do this:
When to use the current SUB token in Perl?
Since Perl 5.16.0, the __SUB__ token is available under use feature ‘current_sub’ and use 5.16.0. It will evaluate to a reference to the currently-running sub, which allows for recursive calls without knowing your subroutine’s name.