vastly improved selection system

crates/forth/src/vm.rs

@@ -625,6 +625,16 @@ impl Forth {
                         .insert("__tempo__".to_string(), Value::Float(clamped, None));
                 }
 
+                Op::SetSpeed => {
+                    let speed = stack.pop().ok_or("stack underflow")?.as_float()?;
+                    let clamped = speed.clamp(0.125, 8.0);
+                    let key = format!("__speed_{}_{}__", ctx.bank, ctx.pattern);
+                    self.vars
+                        .lock()
+                        .unwrap()
+                        .insert(key, Value::Float(clamped, None));
+                }
+
                 Op::Chain => {
                     let pattern = stack.pop().ok_or("stack underflow")?.as_int()? - 1;
                     let bank = stack.pop().ok_or("stack underflow")?.as_int()? - 1;