/home/duff/git/rakudo/src/core [nom *+$ u=]
➤ vi operators.pm
/home/duff/git/rakudo/src/core [nom *+$ u=]
➤ git diff
diff --cc src/core/operators.pm
index f6a0eec,acffab3..0000000
--- a/src/core/operators.pm
+++ b/src/core/operators.pm
@@@ -90,6 -90,58 +90,57 @@@ sub SEQUENCE($left, $right, :$exclude_e
          ($cmp < 0) ?? { $^x.succ } !! ( $cmp > 0 ?? { $^x.pred } !! { $^x } )
      }

+     my sub sequence_generator($tail) {
 -        $tail.munch($tail.elems - 3) if $tail.elems > 3;
+         my $a = $tail[0];
+         my $b = $tail[1];
+         my $c = $tail[2];
+         my $generator;
+         if $tail.grep({ $_ ~~ Numeric}).elems != $tail.elems {
+             # non-numeric
+             if $tail.elems == 1 {
+                 $generator = $infinite ??  { $^x.succ } !! succpred($a cmp $endpoint);
+             }
+             else {
+                 $generator = succpred($tail[*-2] cmp $tail[*-1]);
+             }
+         }
+         elsif $tail.elems == 3 {
+             my $ab = $b - $a;
+             if $ab == $c - $b {
+                 if $ab != 0 || $a ~~ Numeric && $b ~~ Numeric && $c ~~ Numeric {
+                     $generator = { $^x + $ab }
+                 }
+                 else {
+                     $generator = succpred($b cmp $c)
+                 }
+             }
+             elsif $a != 0 && $b != 0 && $c != 0 {
+                 $ab = $b / $a;
+                 if $ab == $c / $b {
+                     $ab = $ab.Int if $ab ~~ Rat && $ab.denominator == 1;
+                     $generator = { $^x * $ab }
+                 }
+             }
+         }
+         elsif $tail.elems == 2 {
+             my $ab = $b - $a;
+             if $ab != 0 || $a ~~ Numeric && $b ~~ Numeric {
+                 $generator = { $^x + $ab }
+             }
+             else {
+                 $generator = succpred($a cmp $b)
+             }
+         }
+         elsif $tail.elems == 1 {
+             $generator = $a cmp $endpoint > 0 ?? { $^x.pred } !! { $^x.succ }
+         }
+         elsif $tail.elems == 0 {
+             $generator = {()}
+         }
+         return $generator;
+     }
+
+
      (GATHER({
/home/duff/git/rakudo/src/core [nom *+$ u=]
➤ vi operators.pm
/home/duff/git/rakudo/src/core [nom *+$ u=]
➤ git diff
diff --cc src/core/operators.pm
index f6a0eec,acffab3..0000000
--- a/src/core/operators.pm
+++ b/src/core/operators.pm
/home/duff/git/rakudo/src/core [nom *+$ u=]
➤ git st
# On branch nom
# Unmerged paths:
#   (use "git reset HEAD <file>..." to unstage)
#   (use "git add/rm <file>..." as appropriate to mark resolution)
#
#	both modified:      operators.pm
#
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#	../../foo.t
no changes added to commit (use "git add" and/or "git commit -a")
/home/duff/git/rakudo/src/core [nom *+$ u=]
➤