lib/text: `FlatString::substring` returns "" on count == 0 or less

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

diff --git a/lib/core/text/flat.nit b/lib/core/text/flat.nit
index 9a70db8..47b8608 100644 (file)
--- a/lib/core/text/flat.nit
+++ b/lib/core/text/flat.nit
@@ -370,7 +370,7 @@ class FlatString
 
        redef fun substring(from, count)
        do
-               assert count >= 0
+               if count <= 0 then return ""
 
                if from < 0 then
                        count += from