"set term" between plots

[Mojca M. <moj...@gm...>]

Hello,

this is not problematic for "clever users", but it might sometimes
lead to unexpected results.

Suppose that the user says:

set output "something.ps"
set term post (or some other terminal)
plot sin(x)
plot cos(x)
set term post color
plot erf(x)

png & friends simply overwrite the existing image file, but PostScript
driver writes out a file that could probably be considered "broken".

"set term post" finishes the old file and writes the header of a "new
file" to the same document. I would expect gnuplot to either:
- do some changes between the two plots (change color setting in that
case) and then continue plotting with new settings (but that requires
heavy changes in terminal sources): so it would draw all the three
graphs
- start from scratch (overwrite the existing plot): so it would only draw erf(x)

I'm asking because my terminal would currently behave really strange
in such a situation. For the example above
- in one (standalone) mode it would only draw sin(x) and cos(x) and
exit (I can't do anything about it)
- in the other mode it would currently draw erf(x) and cos(x), both in
color; I can and would probably change it to draw erf(x) only, but I
still find that behaviour a bit confusing

Any suggestions?

Thanks,
    Mojca