This does what you want

$ perl -e 'use strict;
sub input{
  my (@params) = $_[0] =~ m/([\S]+)/g;
  print scalar @params ," parameters supplied\n";
}
input(join " ", @ARGV);
' Fear Anger Hate Darkside
4 parameters supplied
[download]

Update: Changed \w to \S as original question was split on multiple space characters (thanks to cdarke for spotting this) and modified argument list.