Second, here's a patch that adds seq_concat, which is almost identical to seq_series. (In fact, the patch redefines the latter in terms of the former.)

diff -urN amlfsp1/ex17.pl amlfsp1.new/ex17.pl
--- amlfsp1/ex17.pl    2005-03-09 15:22:08.000000000 -0500
+++ amlfsp1.new/ex17.pl    2005-03-10 20:53:15.660873854 -0500
@@ -11,5 +11,5 @@
 
 seq(1..3)->seq_map(\&supto)->seq_concat->enumerate;
 
-#seq(1..3)->seq_concatmap(\&supto)->enumerate;
+seq(1..3)->seq_concatmap(\&supto)->enumerate;
 
diff -urN amlfsp1/Sequences.pm amlfsp1.new/Sequences.pm
--- amlfsp1/Sequences.pm    2005-03-10 13:38:12.000000000 -0500
+++ amlfsp1.new/Sequences.pm    2005-03-10 20:56:21.166003398 -0500
@@ -101,7 +101,11 @@
 }
 
 sub seq_series {
-    my $seqs = seq( @_ );
+    seq( @_ )->seq_concat;
+}
+
+sub seq_concat {
+    my $seqs = shift;
     my $seq;
     seqsub {
         my @val;
@@ -166,19 +170,6 @@
     wantarray ? @accum : $accum[0];
 }
 
-sub seq_concat {  # FIXME: there's probably a slicker way of doing th
+is...
-    my $seq = shift;
-    my @cache;
-    while (my @seqs = $seq->()) {
-        foreach my $s (@seqs) {
-            while (my @vals = $s->()) {
-                push @cache, @vals;
-            }
-        }
-    }
-    seq(@cache);
-}
-
 sub seq_concatmap {
     my ($seq, $fn) = @_;
     $seq->seq_map($fn)->seq_concat;
[download]

To apply the patch (on a Unix-esque system), save it into a file, "cd" into the directory containing Sequences.pm, and then run this command: "patch -p1 < patchfile".

Cheers,
Tom