lib: do not ignore key/values when value is null in Map::join

Signed-off-by: Alexis Laferrière <alexis.laf@xymus.net>

diff --git a/lib/standard/string.nit b/lib/standard/string.nit
index e159dfc..4326d04 100644 (file)
--- a/lib/standard/string.nit
+++ b/lib/standard/string.nit
@@ -1060,15 +1060,15 @@ redef class Map[K,V]
                var i = iterator
                var k = i.key
                var e = i.item
-               if e != null then s.append("{k}{couple_sep}{e}")
-               
+               s.append("{k}{couple_sep}{e or else "<null>"}")
+
                # Concat other items
                i.next
                while i.is_ok do
                        s.append(sep)
                        k = i.key
                        e = i.item
-                       if e != null then s.append("{k}{couple_sep}{e}")
+                       s.append("{k}{couple_sep}{e or else "<null>"}")
                        i.next
                end
                return s.to_s