plotting lines that break if data break

Hi,

Sometimes data series (not necessarily time series) suffer breaks
where data were expected, but not collected. Often the regular
"lines" command to add such data to a plot is what I want, but other
times I'd like the line to break where the data series is
interrupted, instead of the line jumping to the next point in the
series uninterrupted. Usually my data file contain one value of x but
none of y, but alternatively a break could also appear as a NA value
for both x and y.

I have found I could use the "segments" command instead of "lines",
but this seems to require I manipulate my data (which may or may not
contain breaks, and the number of breaks can vary if there are breaks
at all).

Is there another command that works like "lines" but will break the
line if the data series suffer an interruption?

Sincerely,

Denis Chabot