command: omitting the range end is possible

When the range end is missing, then the maximum possible value is
assumed.

NEWS

@@ -9,6 +9,7 @@ ver 0.16 (20??/??/??)
   - "addid" with negative position is deprecated
   - "load" supports remote playlists (m3u, pls, xspf, lastfm://)
   - allow changing replay gain mode on-the-fly
+  - omitting the range end is possible
 * input:
   - lastfm: obsolete plugin removed
 * tags:

doc/protocol.xml

@@ -67,6 +67,20 @@
         successful command executed in the command list.
       </para>
     </section>
+
+    <section>
+      <title>Ranges</title>
+
+      <para>
+        Some commands (e.g. <link
+        linkend="command_delete"><command>delete</command></link>)
+        allow specifying a range in the form
+        <parameter>START:END</parameter> (the <varname>END</varname>
+        item is not included in the range, similar to ranges in the
+        Python programming language).  If <varname>END</varname> is
+        omitted, then the maximum possible value is assumed.
+      </para>
+    </section>
   </chapter>
 
   <chapter>

src/command.c

@@ -221,7 +221,7 @@ check_range(struct client *client, unsigned *value_r1, unsigned *value_r2,
 
 	if (*test == ':') {
 		value = strtol(++test, &test2, 10);
-		if (*test2 != '\0' || test == test2) {
+		if (*test2 != '\0') {
 			va_list args;
 			va_start(args, fmt);
 			command_error_v(client, ACK_ERROR_ARG, fmt, args);
@@ -229,6 +229,9 @@ check_range(struct client *client, unsigned *value_r1, unsigned *value_r2,
 			return false;
 		}
 
+		if (test == test2)
+			value = G_MAXUINT;
+
 		if (value < 0) {
 			command_error(client, ACK_ERROR_ARG,
 				      "Number is negative: %s", s);