oil AST

(command.CommandList
  children: [
    (command.ShAssignment
      left: <Id.Lit_VarLike 'ld='>
      pairs: [
        (AssignPair
          left: <Id.Lit_VarLike 'ld='>
          lhs: (sh_lhs_expr.Name left:<Id.Lit_VarLike 'ld='> name:ld)
          op: assign_op.Equal
          rhs: 
            {
              (DQ 
                (CommandSub
                  left_token: <Id.Left_Backtick '`'>
                  child: 
                    (command.Simple
                      blame_tok: <head>
                      more_env: []
                      words: [{<head>} {<-1>} {<conf-ld>}]
                      redirects: []
                      do_fork: T
                    )
                  right: <Id.Backtick_Right '`'>
                )
              )
            }
        )
      ]
      redirects: []
    )
    (command.ShAssignment
      left: <Id.Lit_VarLike 'systype='>
      pairs: [
        (AssignPair
          left: <Id.Lit_VarLike 'systype='>
          lhs: (sh_lhs_expr.Name left:<Id.Lit_VarLike 'systype='> name:systype)
          op: assign_op.Equal
          rhs: 
            {
              (DQ 
                (CommandSub
                  left_token: <Id.Left_Backtick '`'>
                  child: 
                    (command.Simple
                      blame_tok: <cat>
                      more_env: []
                      words: [{<cat>} {<systype>}]
                      redirects: []
                      do_fork: T
                    )
                  right: <Id.Backtick_Right '`'>
                )
              )
            }
        )
      ]
      redirects: []
    )
    (command.Simple
      blame_tok: <cat>
      more_env: []
      words: [{<cat>} {<warn-auto.sh>}]
      redirects: []
      do_fork: T
    )
    (command.Simple
      blame_tok: <echo>
      more_env: []
      words: [{<echo>} {(SQ <'main="$1"; shift'>)}]
      redirects: []
      do_fork: T
    )
    (command.Simple
      blame_tok: <echo>
      more_env: []
      words: [{<echo>} {<exec>} {(DQ ($ Id.VSub_DollarName ld))} {(SQ <'-o "$main" "$main".o ${1+"$@"}'>)}]
      redirects: []
      do_fork: T
    )
  ]
)