[pstricks] Accessing data in files on disk

[Alan Ristow]

Hi,

I am trying to write some highly customized plotting routines. Ideally,
my data would be stored in a text file on disk, and could come in one,
two, or more columns. Is there a simple way to access this data, one
point at a time, after it has been read by \readdata? Clearly PSTricks
does this somehow in pst-plot, but after poring over the code for awhile
I can't figure out how. I'm going to continue looking at it this
evening, but in the meantime I'd appreciate any pointers that anybody
might be able to offer. Thanks!

alan