Re: MISSING and UNDEFINED

[Ethan A M. <merritt@u.washington.edu>]

On Sunday 18 June 2006 11:19 am, Daniel J Sebald wrote:
> There are about four bug reports related to handling of 
> MISSING and/or UNDEFINED data points in a file.

This was explicitly listed in my original summary of 
"What's left for a 4.2 release?".

> I think the patch I sent yesterday is close to a solution.

The main problem is that there is no clear agreement on
what the behavior is *supposed* to be.  Without such a 
statement, it's pointless to produce patches.

Version 4.0 does not behave as the docs state.
Is this a bug in the code, or in the docs?
Which do we want to fix?

Disregarding what the docs say, is the handling of
missing/undefined/garbage data consistent in all code paths?

FWIW, my own feeling is that a data line containing a field marked
MISSING  (i.e. it matches the string set by `set datafile missing "X"`)
should be treated as if the entire line were not there at all, 
save maybe for incrementing the line count.  This is not necessarily
the same as treating it as "undefined" or "garbage in the input field".
In other words, I think the description in the docs should be changed.
That is not to say that the code is bug-free, however. 

> Ethan, could you please have a look at that and maybe 
> we can clear out several bug reports with one patch.    

That has been the idea since the beginning.
But first I'd like to see if the "one patch" can be a
patch to gnuplot.doc, or whether we need to patch the
code anyway.


-- 
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle 98195-7742