Re: irreversibly reversing range

[Daniel J S. <dan...@ie...>]

I see there is new behavior for the option "reverse" for gnuplot version 
4.7+.  It seems to me the change is that "{no}reverse" now only applies 
to autoscaling.  (In fact, the documentation ostensibly says that.)

Could someone write a one or two sentence summary of why the change. 
E.g., the previous behavior was too confusing or caused a conflict?  I 
just want to be able to explain why the change if asked.

Reverse axes aren't used real often, except in the case of y-axis and 
images where it is quite common to see the origin in the upper left 
corner of a plot.  (Octave will need a change to address this.)

I also want to confirm that the new behavior is really what is desired. 
  If there is something that may have been wrong with the previous 
behavior it is that the old syntax was too flexible.  I think it was 
Ethan that pointed out controlling the axis from within the plot command 
itself was problematic, e.g.,

plot [0:500] x

I see the point in the sense that multiple items with different range 
settings can be a conflict.  Maybe we shouldn't think of the range 
specified within the plot command as "axis range".

Perhaps it is the fact that range setting itself can control the 
orientation of an axes, i.e., [500:0].  If that were disallowed, then 
there would still be an ability to control range within the plot 
command, but not be able to control the orientation of the axis.

So rather than the change "reverse only applies to autoscaling", another 
change could have been "range limits no longer control orientation".  So 
that would mean

set xrange [0:500]
set xrange [500:0]
plot [0:500]
plot [500:0]

all mean the same thing, i.e., the xaxis range is from 0 to 500 using 
the typical Cartesian orientation.  Also

set xrange [0:500] reverse
set xrange [500:0] reverse
set xrange reverse
plot [0:500]
set xrange reverse
plot [500:0]

would all mean the same thing, i.e., the xaxis range is from 0 to 500 
but using the reverse orientation.

Dan