script: add length

plugins/script

@@ -910,6 +910,35 @@ defn (fn_to_float)
 	return true;
 }
 
+// - - Miscellaneous - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+defn (fn_length)
+{
+	check_stack (1);
+	struct item *item = pop (ctx);
+	bool success = true;
+	switch (item->type)
+	{
+	case ITEM_STRING:
+		push (ctx, new_integer (((struct item_string *) item)->len));
+		break;
+	case ITEM_LIST:
+	{
+		long long length = 0;
+		struct item *iter;
+		for (iter = get_list (item); iter; iter = iter->next)
+			length++;
+		push (ctx, new_integer (length));
+		break;
+	}
+	default:
+		ctx->error = strdup ("invalid type");
+		success = false;
+	}
+	item_free (item);
+	return success;
+}
+
 // - - Stack operations  - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
 defn (fn_dup)
@@ -1654,7 +1683,6 @@ item_list_to_str (const struct item *script, struct buffer *buf)
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
 // TODO: implement more functions; try to avoid writing it in C
-//   length -- length of a list/string
 //   -, /, %, ** -- arithmetic
 //   at { value index -- sub-value } -- get n-th subvalue of a string/list
 
@@ -1687,7 +1715,7 @@ init_runtime_library_scripts (void)
 		struct item *script = parse (scripts[i].definition, &error);
 		if (error)
 		{
-			fprintf (stderr, "error parsing internal script `%s': %s=n",
+			fprintf (stderr, "error parsing internal script `%s': %s\n",
 				scripts[i].definition, error);
 			free (error);
 			exit (EXIT_FAILURE);
@@ -1713,6 +1741,9 @@ init_runtime_library (void)
 	register_handler (">integer", fn_to_integer);
 	register_handler (">float",   fn_to_float);
 
+	// Miscellaneous
+	register_handler ("length",   fn_length);
+
 	// Basic stack manipulation
 	register_handler ("dup",      fn_dup);
 	register_handler ("drop",     fn_drop);