package Nix::Utils;
$urlRE = "(?: [a-zA-Z][a-zA-Z0-9\+\-\.]*\:[a-zA-Z0-9\%\/\?\:\@\&\=\+\$\,\-\_\.\!\~\*]+ )";
sub checkURL {
my ($url) = @_;
die "invalid URL ‘$url’\n" unless $url =~ /^ $urlRE $ /x;
}
sub uniq {
my %seen;
my @res;
foreach my $name (@_) {
next if $seen{$name};
$seen{$name} = 1;
push @res, $name;
return @res;