#! /usr/bin/perl

my $string = q/allow:test1,"@test 2 " deny:test3,test4 password:"123   456"/;

while ($string =~ s/(\w+):(.*?)($|(?=\w+:))//) {
  print "Argument: $1\n";
  my @params = split /,/,$2;
  print "  Param: $_\n" foreach (@params);
}