diff --git a/src/lang.zig b/src/lang.zig
index 03a6c52..a455a1f 100644
--- a/src/lang.zig
+++ b/src/lang.zig
@@ -31,23 +31,6 @@ fn LV2Command(
     };
 }
 
-fn CustomCommand(
-    comptime tag: Command.tag,
-    comptime plugin: type,
-    comptime parameters: type,
-) type {
-    return struct {
-        pub const base_tag = tag;
-        pub const command_type = CommandType.plugin_command;
-        pub const plugin_type = plugin;
-
-        base: Command,
-        split: usize,
-        index: usize,
-        parameters: LV2Parameters,
-    };
-}
-
 pub const Command = struct {
     tag: Tag,
 
@@ -130,13 +113,6 @@ pub const Command = struct {
             .saturator => Saturator,
             .vintagedelay => Vintagedelay,
 
-            .noise => Noise,
-            .wildnoise => Wildnoise,
-            .write => Write,
-            .embed => Embed,
-
-            .rotate => Rotate,
-
             else => @panic("TODO"),
         };
     }
@@ -170,37 +146,8 @@ pub const Command = struct {
 
     pub const RunQS = struct {
         pub const base_tag = Tag.runqs;
-        base: Command,
         program: []const u8,
-    };
-
-    pub const Noise = CustomCommand(Tag.noise, custom.RandomNoise, struct {
-        seed: f32,
-        fill_bytes: f32,
-    });
-
-    pub const Wildnoise = CustomCommand(Tag.wildnoise, custom.WildNoise, struct {
-        seed: f32,
-        fill_bytes: f32,
-    });
-
-    pub const Write = CustomCommand(Tag.write, custom.Write, struct {
-        data: f32,
-    });
-
-    pub const Embed = struct {
-        pub const base_tag = Tag.embed;
         base: Command,
-        split: usize,
-        index: usize,
-        path: []const u8,
-    };
-
-    pub const Rotate = struct {
-        pub const base_tag = Tag.rotate;
-        base: Command,
-        deg: f32,
-        bgfill: []const u8,
     };
 
     pub const Amp = LV2Command(
@@ -415,14 +362,9 @@ 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,
@@ -506,7 +448,7 @@ pub const Lang = struct {
         self.line = 0;
     }
     fn doError(self: *Lang, comptime fmt: []const u8, args: var) void {
-        std.debug.warn("ERROR! at line {}: ", .{self.line});
+        std.debug.warn("error at line {}: ", .{self.line});
         std.debug.warn(fmt, args);
         std.debug.warn("\n", .{});
         self.has_error = true;
@@ -529,34 +471,23 @@ pub const Lang = struct {
         // arguments...
 
         if (is_lv2_command) {
-            const split = tok_it.next();
-            if (split == null) {
-                self.doError("Expected split parameter, got EOL", .{});
-                return;
-            }
+            cmd.split = try std.fmt.parseInt(usize, tok_it.next().?, 10);
+            cmd.index = try std.fmt.parseInt(usize, tok_it.next().?, 10);
 
-            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);
-
-            // All parameters for LV2 plugins are f32.
             inline for (@typeInfo(@TypeOf(cmd.parameters)).Struct.fields) |cmd_field| {
-                const maybe_arg = tok_it.next();
-                if (maybe_arg == null) {
-                    self.doError("Expected parameter for {}, got nothing", .{cmd_field.name});
-                    return;
-                }
+                const arg = tok_it.next().?;
+                const argument_value = switch (cmd_field.field_type) {
+                    f32 => try std.fmt.parseFloat(f32, arg),
+                    else => @compileError("LV2 parameter struct can only have f32 fields"),
+                };
 
-                const arg = maybe_arg.?;
-                if (cmd_field.field_type != f32)
-                    @compileError("LV2 parameter struct can only have f32 fields");
+                std.debug.warn("parsing {}, arg of type {} => {}\n", .{
+                    @typeName(command_struct),
+                    @typeName(@TypeOf(argument_value)),
+                    argument_value,
+                });
 
-                @field(cmd.parameters, cmd_field.name) = try std.fmt.parseFloat(f32, arg);
+                @field(cmd.parameters, cmd_field.name) = argument_value;
             }
         } else {
             inline for (@typeInfo(command_struct).Struct.fields) |cmd_field| {