(command.CommandList
  children: [
    (command.ShAssignment
      pairs: [
        (assign_pair
          lhs: (sh_lhs_expr.Name name:CHROMIUM_DIR)
          op: assign_op.Equal
          rhs: 
            {
              (DQ 
                (command_sub
                  left_token: <Id.Left_DollarParen '$('>
                  child: (C {<dirname>} {($ Id.VSub_DollarName '$BASH_SOURCE')})
                )
              )
            }
          spids: [20]
        )
      ]
    )
    (command.ShAssignment
      pairs: [
        (assign_pair
          lhs: (sh_lhs_expr.Name name:SDK_BIN)
          op: assign_op.Equal
          rhs: {(DQ ($ Id.VSub_DollarName '$CHROMIUM_DIR') <'/../dart-sdk/bin'>)}
          spids: [29]
        )
      ]
    )
    (command.ShAssignment
      pairs: [
        (assign_pair
          lhs: (sh_lhs_expr.Name name:DART)
          op: assign_op.Equal
          rhs: {(DQ ($ Id.VSub_DollarName '$SDK_BIN') <'/dart'>)}
          spids: [36]
        )
      ]
    )
    (command.ShAssignment
      pairs: [
        (assign_pair
          lhs: (sh_lhs_expr.Name name:DOWNLOAD_SCRIPT)
          op: assign_op.Equal
          rhs: {(DQ ($ Id.VSub_DollarName '$CHROMIUM_DIR') <'/download_file.dart'>)}
          spids: [42]
        )
      ]
    )
    (C {(DQ ($ Id.VSub_DollarName '$DART'))} {(DQ ($ Id.VSub_DollarName '$DOWNLOAD_SCRIPT'))} 
      {(DQ <VAR_DOWNLOAD_URL>)} {(DQ <VAR_DESTINATION>)}
    )
  ]
)