Question

I have a subroutine, which gets a hashreference as a parameter.

I can manipulate single hashvalues by reference.
I want to replace the whole hash, which the reference point at, so that everywhere, where this hash was references the changes become visible.

sub replace{
    my $hashref = shift;

    # can manipulate hash here
    $hashref->{key} = "newValue";

    # how to replace replace the hash here by a new hash
    $newHashRef = {
        key  => "value",
        key2 => "value2",
    };
}

Is that possible?

Answer 1

%$hashref = (
    key => "value",
    key2 => "value2",
);

%$hashref denotes “the hash that $hashref refers to”, and assigning to that hash replaces its contents, just as it would if no reference was involved.