pub trait Machine {
// Required methods
fn stack_from_base(&self, base: usize) -> Cow<'_, [Value]>;
fn blobs(&self) -> &[Blob];
fn eval_op(&mut self, op: Op) -> Result<OpResult, Error>;
fn eval_call(
&mut self,
callable: Value,
args: &[&Value],
) -> Result<Value, Error>;
fn args(&self) -> &[String];
}