From 938cb3ef5883b4a863d755409943eeda99f0df52 Mon Sep 17 00:00:00 2001
From: Patrick Abi Salloum <patrick.abisalloum@gmail.com>
Date: Mon, 30 Aug 2010 18:55:41 +0300
Subject: [PATCH] is-on-the-wrong-side only returns true when the rhs is on the
 wrong side of ALL the lhs

---
 src/core/operators.pm | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/src/core/operators.pm b/src/core/operators.pm
index 25b6c7a833a..3f273cb4598 100644
--- a/src/core/operators.pm
+++ b/src/core/operators.pm
@@ -386,14 +386,29 @@ our sub _HELPER_generate-series(@lhs, $rhs , :$exclude-limit) {
     }
 
     my sub is-on-the-wrong-side($type , $get-value-to-compare, $limit , @lhs ) {
-        my $first = @lhs[*-3] // @lhs[0];
         return if $limit ~~ Code;
-
-        if $type eq 'arithmetic' | 'geometric-switching-sign' | 'geometric-same-sign' {
-            ($get-value-to-compare(@lhs[*-2]) >= $get-value-to-compare(@lhs[*-1]) && $get-value-to-compare($limit) > $get-value-to-compare($first) )
+        return unless $type eq 'arithmetic' | 'geometric-switching-sign' | 'geometric-same-sign';
+
+        my $first = $get-value-to-compare( @lhs[*-3] // @lhs[0] );
+        my $second = $get-value-to-compare( @lhs[*-2] );
+        my $third = $get-value-to-compare( @lhs[*-1] );
+        my $limit-to-use = $get-value-to-compare( $limit );
+        return unless ($second >= $third && $limit-to-use > $first )
+                ||
+                ($second  <= $third && $limit-to-use < $first );
+
+        sub between($a , $b) {
+            my ( $first , $second ) = ( $get-value-to-compare($a) , $get-value-to-compare($b) );
+            ($first >= $limit-to-use >= $second )
             ||
-            ($get-value-to-compare(@lhs[*-2]) <= $get-value-to-compare(@lhs[*-1]) && $get-value-to-compare($limit) < $get-value-to-compare($first) );
+            ($first <= $limit-to-use <= $second )
+        }
+
+        my $i = @lhs.elems;
+        while ($i-- >1) {
+            return if between(@lhs[$i-1] , @lhs[$i]); #If the limit is between any two items it cannot be on the wrong side
         }
+        return True;
     }
 
     my sub infinite-series (@lhs, $next ) {