Feat: introduce follow up actions

crates/forth/src/vm.rs

@@ -992,26 +992,6 @@ impl Forth {
                         .insert(ctx.speed_key.to_string(), Value::Float(clamped, None));
                 }
 
-                Op::Chain => {
-                    let pattern = pop_int(stack)? - 1;
-                    let bank = pop_int(stack)? - 1;
-                    if bank < 0 || pattern < 0 {
-                        return Err("chain: bank and pattern must be >= 1".into());
-                    }
-                    if bank as usize == ctx.bank && pattern as usize == ctx.pattern {
-                        // chaining to self is a no-op
-                    } else {
-                        use std::fmt::Write;
-                        let mut val = String::with_capacity(8);
-                        let _ = write!(&mut val, "{bank}:{pattern}");
-                        var_writes_cell
-                            .borrow_mut()
-                            .as_mut()
-                            .expect("var_writes taken")
-                            .insert(ctx.chain_key.to_string(), Value::Str(Arc::from(val), None));
-                    }
-                }
-
                 Op::Loop => {
                     let beats = pop_float(stack)?;
                     if ctx.tempo == 0.0 || ctx.speed == 0.0 {