oil AST

(command.CommandList
  children: [
    (command.ShFunction
      name: usage
      body: 
        (BraceGroup
          children: [
            (C {<echo>} {(DQ <'Usage: '> ($ Id.VSub_Number '$0') <' <target>'>)})
            (command.ControlFlow token:<Id.ControlFlow_Exit exit> arg_word:{<2>})
          ]
        )
    )
    (command.AndOr
      ops: [Id.Op_DAmp]
      children: [(C {<test>} {<-z>} {(DQ ($ Id.VSub_Number '$1'))}) (C {<usage>})]
    )
    (command.ShAssignment
      pairs: [
        (assign_pair
          lhs: (sh_lhs_expr.Name name:package)
          op: assign_op.Equal
          rhs: {($ Id.VSub_Number '$1')}
          spids: [61]
        )
      ]
    )
    (C {<cd>} 
      {(command_sub left_token:<Id.Left_Backtick '`'> child:(C {<dirname>} {($ Id.VSub_Number '$0')}))}
    )
    (command.ShAssignment
      pairs: [
        (assign_pair
          lhs: (sh_lhs_expr.Name name:conf_file)
          op: assign_op.Equal
          rhs: {($ Id.VSub_DollarName '$package') <'/configure.in'>}
          spids: [76]
        )
      ]
    )
    (command.ShAssignment
      pairs: [
        (assign_pair
          lhs: (sh_lhs_expr.Name name:version)
          op: assign_op.Equal
          rhs: 
            {
              (command_sub
                left_token: <Id.Left_Backtick '`'>
                child: 
                  (command.Pipeline
                    children: [
                      (C {<cat>} {($ Id.VSub_DollarName '$conf_file')})
                      (C {<sed>} {<-ne>} 
                        {(SQ <'/AC_INIT.*'>) ($ Id.VSub_DollarName '$package') (SQ <'.*/s/^AC_INIT.*'>) 
                          ($ Id.VSub_DollarName '$package') (SQ <', \\(.*\\),.*$/\\1/p'>)
                        }
                      )
                    ]
                    negated: F
                  )
              )
            }
          spids: [80]
        )
      ]
    )
    (command.Simple
      words: [
        {<git>}
        {<diff>}
        {<--quiet>}
        {($ Id.VSub_DollarName '$package') <-> ($ Id.VSub_DollarName '$version') <..HEAD>}
        {<-->}
        {($ Id.VSub_DollarName '$package')}
      ]
      redirects: [
        (redir op:<Id.Redir_Great '>'> loc:(redir_loc.Fd fd:1) arg:{<'/dev/null'>})
        (redir op:<Id.Redir_GreatAnd '2>&'> loc:(redir_loc.Fd fd:2) arg:{<1>})
      ]
      do_fork: T
    )
    (command.If
      arms: [
        (if_arm
          cond: [
            (command.Sentence
              child: 
                (C {<Id.Lit_LBracket '['>} {($ Id.VSub_QMark '$?')} {<-eq>} {<1>} {<Id.Lit_RBracket ']'>})
              terminator: <Id.Op_Semi _>
            )
          ]
          action: [
            (command.ShAssignment
              pairs: [
                (assign_pair
                  lhs: (sh_lhs_expr.Name name:abbr)
                  op: assign_op.Equal
                  rhs: 
                    {
                      (command_sub
                        left_token: <Id.Left_Backtick '`'>
                        child: 
                          (command.Simple
                            words: [{<git>} {<rev-parse>} {<--short>} {<--verify>} {<HEAD>}]
                            redirects: [
                              (redir
                                op: <Id.Redir_Great '2>'>
                                loc: (redir_loc.Fd fd:2)
                                arg: {<'/dev/null'>}
                              )
                            ]
                            do_fork: T
                          )
                      )
                    }
                  spids: [153]
                )
              ]
            )
            (command.If
              arms: [
                (if_arm
                  cond: [
                    (command.Sentence
                      child: 
                        (C {<Id.Lit_LBracket '['>} {<Id.KW_Bang '!'>} {<-z>} 
                          {(DQ ($ Id.VSub_DollarName '$abbr'))} {<Id.Lit_RBracket ']'>}
                        )
                      terminator: <Id.Op_Semi _>
                    )
                  ]
                  action: [
                    (command.ShAssignment
                      pairs: [
                        (assign_pair
                          lhs: (sh_lhs_expr.Name name:version)
                          op: assign_op.Equal
                          rhs: {(DQ (${ Id.VSub_Name version) <_> (${ Id.VSub_Name abbr))}
                          spids: [191]
                        )
                      ]
                    )
                  ]
                  spids: [172 188]
                )
              ]
            )
          ]
          spids: [136 150]
        )
      ]
    )
    (command.Simple
      words: [{<git>} {<diff-index>} {<--quiet>} {<HEAD>} {<-->} {($ Id.VSub_DollarName '$package')}]
      redirects: [
        (redir op:<Id.Redir_Great '>'> loc:(redir_loc.Fd fd:1) arg:{<'/dev/null'>})
        (redir op:<Id.Redir_GreatAnd '2>&'> loc:(redir_loc.Fd fd:2) arg:{<1>})
      ]
      do_fork: T
    )
    (command.If
      arms: [
        (if_arm
          cond: [
            (command.Sentence
              child: 
                (C {<Id.Lit_LBracket '['>} {($ Id.VSub_QMark '$?')} {<-eq>} {<1>} {<Id.Lit_RBracket ']'>})
              terminator: <Id.Op_Semi _>
            )
          ]
          action: [
            (command.ShAssignment
              pairs: [
                (assign_pair
                  lhs: (sh_lhs_expr.Name name:version)
                  op: assign_op.Equal
                  rhs: {(DQ (${ Id.VSub_Name version) <_dirty>)}
                  spids: [244]
                )
              ]
            )
          ]
          spids: [227 241]
        )
      ]
    )
    (C {<echo>} {($ Id.VSub_DollarName '$version')})
  ]
)