TODO #!/usr/bin/env bash

# Provides an "atexit" mechanism for scripts.

# Array of commands to eval.
declare -a __atexit_cmds = ''

# Helper for eval'ing commands.
proc __atexit {
    for cmd in [$(__atexit_cmds[@])] {
        eval $(cmd)
    }
}

# Usage: atexit command arg1 arg2 arg3
proc atexit {
    # Determine the current number of commands.
    var length = $(#__atexit_cmds[*])

    # Add this command to the end.
    __atexit_cmds[$(length)]="$(*)"

    # Set the trap handler if this was the first command added.
    if [[ ${length} -eq 0 ]] {
        trap __atexit EXIT
    }
}
(CommandList
  children: [
    (Assignment
      keyword: Assign_Declare
      flags: ["'-a'"]
      pairs: [(assign_pair lhs:(LhsName name:__atexit_cmds) op:Equal spids:[15])]
      spids: [11]
    )
    (FuncDef
      name: __atexit
      body: 
        (BraceGroup
          children: [
            (ForEach
              iter_name: cmd
              iter_words: [
                {
                  (DQ 
                    (BracedVarSub
                      token: <VSub_Name __atexit_cmds>
                      bracket_op: (WholeArray op_id:Lit_At)
                      spids: [35 40]
                    )
                  )
                }
              ]
              do_arg_iter: False
              body: (DoGroup children:[(C {(eval)} {(${ VSub_Name cmd)})] spids:[4454])
              spids: [33 42]
            )
          ]
          spids: [25]
        )
      spids: [21 24]
    )
    (FuncDef
      name: atexit
      body: 
        (BraceGroup
          children: [
            (Assignment
              keyword: Assign_Local
              pairs: [
                (assign_pair
                  lhs: (LhsName name:length)
                  op: Equal
                  rhs: 
                    {
                      (BracedVarSub
                        token: <VSub_Name __atexit_cmds>
                        prefix_op: VSub_Pound
                        bracket_op: (WholeArray op_id:Arith_Star)
                        spids: [76 82]
                      )
                    }
                  spids: [75]
                )
              ]
              spids: [73]
            )
            (C 
              {(__atexit_cmds) (Lit_Other "[") (${ VSub_Name length) (Lit_Other "]") (Lit_Other "=") 
                (DQ (${ VSub_Star "*"))
              }
            )
            (If
              arms: [
                (if_arm
                  cond: [
                    (Sentence
                      child: 
                        (DBracket
                          expr: 
                            (BoolBinary
                              op_id: BoolBinary_eq
                              left: {(${ VSub_Name length)}
                              right: {(0)}
                            )
                        )
                      terminator: <Op_Semi ";">
                    )
                  ]
                  action: [(C {(trap)} {(__atexit)} {(EXIT)})]
                  spids: [-1 124]
                )
              ]
              spids: [-1 134]
            )
          ]
          spids: [66]
        )
      spids: [62 65]
    )
  ]
)