Second, what if you wanted to pass an arbitrary or unordered list of parameters to a subroutine? Perhaps you sometimes want to supply a particular parameter on some subroutine calls, but not others. Ideally, you should be able to pass key value pairs to a subroutine, so that you can pass arbitrary value lists and assign their variable names at the same time.

This is when you say:

my %parameters = @_;

which allows you to call your subroutine "ideally":

foo( color => 'blue', size => 'really big' );

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Apparently the author is not familiar with this idiom, though it's pretty common.

Update

The author does indeed say,

Sure, one could pass a reference to a hash with these key value pairs

But that is not what I've done. I've passed an ordinary list, not a reference to an anonymous hash. That would be:

foo ( {color => 'blue', size => 'really big'} );

[download]

which would require the subrountine to say something like: 

my %parameters = %{+shift};

[download]

In reply to Re: Perl's warts by Petruchio
in thread Perl's warts by grinder

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