{{{  comments
; simulate the tds-operations TOP and BOTTOM, which jump to top and bottom
; of currently OPENED fold.
}}}
nodup
{{{  top
(deffun mtool-top
  (
    if test-end-fold (O_UP) fi
    while and(not(test-begin-fold),not(test-top)) (
      if test-end-fold (mtool-top) fi
      O_UP
    )
  )
)
}}}
{{{  bot
(deffun mtool-bot
  (
    if test-begin-fold (O_DOWN) fi
    while and(not(test-end-fold),not(test-bottom)) (
      if test-begin-fold (mtool-bot) fi
      O_DOWN
    )
  )
)
}}}