Type Alias ExternalCommandHandler 

pub type ExternalCommandHandler = Box<dyn FnMut(&str, &[String], Option<&[u8]>) -> Option<ExternalCommandResult>>;

Callback type for external (host-provided) commands.

Called with (command_name, argv, stdin). Returns Some(result) if the command was handled, None to fall through to “command not found”.

Aliased Type

pub struct ExternalCommandHandler(/* private fields */);