.. rst-class:: mini-api
- :mini:`type context < function`
- A context key can be used to create context specific values. If :mini:`key` is a context key, then calling :mini:`key()` no arguments returns the value associated with the key in the current context, or :mini:`nil` is no value is associated. Calling :mini:`key(Value, Function)` will invoke :mini:`Function` in a new context where :mini:`key` is associated with :mini:`Value`.
- :mini:`fun context(): context`
- Creates a new context specific key.