(command.CommandList
  children: [
    (command.CommandList
      children: [
        (command.Sentence
          child: 
            (command.ShAssignment
              pairs: [
                (assign_pair
                  lhs: (sh_lhs_expr.Name name:SRCDIR)
                  op: assign_op.Equal
                  rhs: 
                    {
                      (DQ 
                        (command_sub
                          left_token: <Id.Left_DollarParen '$('>
                          child: (C {<dirname>} {(DQ (${ Id.VSub_Number 0))})
                        )
                      )
                    }
                  spids: [7]
                )
              ]
            )
          terminator: <Id.Op_Semi _>
        )
        (C {<export>} {<SRCDIR>})
      ]
    )
    (command.Pipeline
      children: [
        (C {<m4>} {(DQ (${ Id.VSub_Name SRCDIR) <'/../regress.m4'>)} 
          {(DQ (${ Id.VSub_Name SRCDIR) <'/regress.sh'>)}
        )
        (C {<sh>})
      ]
      negated: F
    )
  ]
)