(CommandList
  children: [
    (Assignment
      keyword: Assign_None
      pairs: [
        (assign_pair
          lhs: (LhsName name:dirname)
          op: Equal
          rhs: 
            {
              (BracedVarSub
                token: <VSub_Name BASH_SOURCE>
                suffix_op: (StringUnary op_id:VOp1_Percent arg_word:{(Lit_Slash /) ("*")})
                spids: [13 18]
              )
            }
          spids: [12]
        )
      ]
      spids: [12]
    )
    (C {(source)} {(${ VSub_Name dirname) (/library.sh)})
    (C {(echo)} {(SQ <"script line 7">)})
    (C {(library-function)})
    (C {(echo)} {(SQ <"script line 11">)})
  ]
)