diff --git a/doc/regex.png b/doc/regex.png
new file mode 100644
index 0000000000000000000000000000000000000000..b1a353623de7594928f2c867ad2d71b288dca04e
Binary files /dev/null and b/doc/regex.png differ
diff --git a/lib/commands/parser.pm b/lib/commands/parser.pm
index 95b2b63e142f16a3652c1991d21a9b363fd3d24c..0ae111efa756b53e2b62991aac2ca71731fc302d 100644
--- a/lib/commands/parser.pm
+++ b/lib/commands/parser.pm
@@ -44,6 +44,7 @@ sub exec {
 
     my $re_place_t ="\\ +@\\ +(?<place>[^:]*)";
 
+    # see doc/regex.png for an visualisation of this regex
     if ($msg =~ m=^Sam(?:,|:)                           # hl
             \ +(?<add_user>je\ +(vais|viens)\ +à\ +)?   # add_user
             (?<title>[^@]+)                             # title