Item 47. Use hashes to pass named parameters

Although Perl provides no method of automatically naming parameters in the function to which you pass them (in other words, no “formal parameters” [Item 48]), there’s a variety of ways that you can call functions with an argument list that provides both names and values.

All of these mechanisms require that the function you call do some extra work while processing the argument list. In other words, this feature isn’t built into Perl either, but it’s a blessing in disguise. Different implementations of named parameters are appropriate at different times. Perl makes it easy to write and use almost any implementation you want.