oil AST

(command.CommandList
  children: [
    (C {<printf>} {(DQ <'Status: 500 Intentional Breakage'> <Id.Lit_BadBackslash '\\'> <n>)})
    (C {<printf>} {(DQ <'Content-Type: '>)})
    (command.ShAssignment
      pairs: [
        (assign_pair
          lhs: (sh_lhs_expr.Name name:charset)
          op: assign_op.Equal
          rhs: {<iso-8859-1>}
          spids: [19]
        )
      ]
    )
    (command.Case
      to_match: {(DQ ($ Id.VSub_DollarName '$PATH_INFO'))}
      arms: [
        (case_arm
          pat_list: [{<Id.Lit_Star '*'> <html> <Id.Lit_Star '*'>}]
          action: [(C {<printf>} {(DQ <'text/html'>)})]
          spids: [30 33 43 -1]
        )
        (case_arm
          pat_list: [{<Id.Lit_Star '*'> <text> <Id.Lit_Star '*'>}]
          action: [(C {<printf>} {(DQ <'text/plain'>)})]
          spids: [45 48 58 -1]
        )
        (case_arm
          pat_list: [{<Id.Lit_Star '*'> <charset> <Id.Lit_Star '*'>}]
          action: [
            (C {<printf>} {(DQ <'text/plain; charset=utf-8'>)})
            (command.ShAssignment
              pairs: [
                (assign_pair
                  lhs: (sh_lhs_expr.Name name:charset)
                  op: assign_op.Equal
                  rhs: {<utf-8>}
                  spids: [73]
                )
              ]
            )
          ]
          spids: [60 63 77 -1]
        )
        (case_arm
          pat_list: [{<Id.Lit_Star '*'> <utf16> <Id.Lit_Star '*'>}]
          action: [
            (C {<printf>} {(DQ <'text/plain; charset=utf-16'>)})
            (command.ShAssignment
              pairs: [
                (assign_pair
                  lhs: (sh_lhs_expr.Name name:charset)
                  op: assign_op.Equal
                  rhs: {<utf-16>}
                  spids: [92]
                )
              ]
            )
          ]
          spids: [79 82 96 -1]
        )
        (case_arm
          pat_list: [{<Id.Lit_Star '*'> <odd-spacing> <Id.Lit_Star '*'>}]
          action: [
            (C {<printf>} {(DQ <'text/plain; foo=bar ;charset=utf-16; other=nonsense'>)})
            (command.ShAssignment
              pairs: [
                (assign_pair
                  lhs: (sh_lhs_expr.Name name:charset)
                  op: assign_op.Equal
                  rhs: {<utf-16>}
                  spids: [111]
                )
              ]
            )
          ]
          spids: [98 101 115 -1]
        )
      ]
    )
    (C {<printf>} {(DQ <Id.Lit_BadBackslash '\\'> <n>)})
    (C {<printf>} {(DQ <Id.Lit_BadBackslash '\\'> <n>)})
    (command.Pipeline
      children: [
        (C {<printf>} {(DQ <'this is the error message'> <Id.Lit_BadBackslash '\\'> <n>)})
        (C {<iconv>} {<-f>} {<us-ascii>} {<-t>} {($ Id.VSub_DollarName '$charset')})
      ]
      negated: F
    )
  ]
)