#usage: @result = st_complex sub { complex comparison }, sub { transform }, LIST 
sub st_complex (&&@) {
	my $compare = shift;
	my $transform = shift;
	map { $_->[-1] }
	sort $compare
	map { [ $transform->(), $_ ] } @_;
}

#usage: @result = st_simple sub { transform }, LIST 
#note: comparison is string wise.
sub st_simple (&@) {
	my $transform = shift;
	&st_complex(sub { $a->[0] cmp $b->[0] }, $transform, @_);
}