use crate::semantics::cfg::Cfg;
pub trait DynCtx<Key, Value> {
fn ref_(&self, cfg: &mut Cfg, key: Key) -> Option<&Value>;
fn ref_mut(&mut self, cfg: &mut Cfg, key: Key) -> Option<&mut Value>;
fn set(&mut self, cfg: &mut Cfg, key: Key, value: Value) -> Option<()>;
}