(command.CommandList
  children: [
    (C {<set>} {<-ex>})
    (C {<cp>} {<-r>} 
      {
        (command_sub
          left_token: <Id.Left_DollarParen '$('>
          child: (C {<dirname>} {(DQ ($ Id.VSub_DollarName '$BASH_SOURCE'))})
        ) <'/../../format'>
      } {<'_docs/format'>}
    )
  ]
)