diff --git a/src/lang.zig b/src/lang.zig
index a455a1f..89ed749 100644
--- a/src/lang.zig
+++ b/src/lang.zig
@@ -362,9 +362,14 @@ pub const Command = struct {
         t4d: f32,
         t4a_db: f32,
     });
-    pub const Moddelay = LV2Command(.moddelay, "http://plugin.org.uk/swh-plugins/modDelay", struct {
-        base: f32,
-    });
+
+    pub const Moddelay = LV2Command(
+        .moddelay,
+        "http://plugin.org.uk/swh-plugins/modDelay",
+        struct {
+            base: f32,
+        },
+    );
 
     pub const Multichorus = LV2Command(.multichorus, "http://calf.sourceforge.net/plugins/MultiChorus", struct {
         min_delay: f32,
@@ -471,8 +476,20 @@ pub const Lang = struct {
         // arguments...
 
         if (is_lv2_command) {
-            cmd.split = try std.fmt.parseInt(usize, tok_it.next().?, 10);
-            cmd.index = try std.fmt.parseInt(usize, tok_it.next().?, 10);
+            const split = tok_it.next();
+            if (split == null) {
+                self.doError("Expected split parameter, got EOL", .{});
+                return;
+            }
+
+            const index = tok_it.next();
+            if (index == null) {
+                self.doError("Expected index parameter, got EOL", .{});
+                return;
+            }
+
+            cmd.split = try std.fmt.parseInt(usize, split.?, 10);
+            cmd.index = try std.fmt.parseInt(usize, index.?, 10);
 
             inline for (@typeInfo(@TypeOf(cmd.parameters)).Struct.fields) |cmd_field| {
                 const arg = tok_it.next().?;