DynamicVariables provide a binding mechanism where the current value is found through dynamic scope, but where access to the variable itself is resolved through static scope.

The current value can be retrieved with the value method. New values should be pushed using thewithValue method. Values pushed viawithValue only stay valid while thewithValue's second argument, a parameterless closure, executes. When the second argument finishes, the variable reverts to the previous value.

someDynamicVariable.withValue(newValue) {  // ... code called in here that calls value ...  // ... will be given back the newValue ...}

Each thread gets its own stack of bindings. When a new thread is created, theDynamicVariable gets a copy of the stack of bindings from the parent thread, and from then on the bindings for the new thread are independent of those for the original thread.