As wfsp has said, you can just assign @_ and this will treat the passed list of parameters as a set of key and value pairs. Note that an odd number of params will result in a run time exception.

But, you often want to perform some (often elementary) validation on the input parameters, before casting them to a hash, such as checking that the keys are what you expect. Params::Validate is what I tend to use to do this, though there are other CPAN modules which do similar things. There are plenty of examples of how to use it in the docs.