"open-ended" plot limits?

Hi Folks,
Maybe I've missed it already being available somehow,
but if the following isn't available I'd like to suggest it.

If you're happy to let plot() choose its own limits,
then of course plot(x,y) will do it.

If you know what limits you want, then
  plot(x,y,xlim=c(x0,x1),ylim(y0,y1)
will do it.

But sometimes one would like to
a) make sure that (e.g.) the y-axis has a lower limit (say) 0
b) let plot() choose the upper limit.

In that case, something like

  plot(x,y,ylim=c(0,NA))

would be a natural way of specifying it. But of course that
does not work.

I would like to suggest that this possibility should be available.
What do people think?

Best wishes,
Ted.

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E-Mail: (Ted Harding) <Ted.Harding at manchester.ac.uk>
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Date: 05-Feb-09                                       Time: 20:48:30
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