How to make a new option default during upgrade? (gnuplot/aquaterm)

[Mojca Miklavec]

Hello,

After the discussion about transition from "no_x11" to "x11" and the
need for the following lines

if {[variant_isset no_x11]} {
    default_variants -x11
} else {
    default_variants +x11
}

the following question popped up in my mind. In this suggested patch:
    http://trac.macports.org/attachment/ticket/34423/gnuplot-use-aqt-framework-extra-option.patch
I added a new default option "+aquaterm". This option should be used
by everyone except when explicitly disabled with "-aquaterm". During
upgrade the option +aquaterm should automatically be used.

My question is: how can I add the +aquaterm option and:
- make sure that "port upgrade gnuplot" won't delete aquaterm
- make sure that "port install gnuplot -aquaterm" & "port upgrade
gnuplot" won't install aquaterm

At the same time it might be nice to replace no_x11 with x11 ... and
all those flags & transitional "if"s look like a mess ;)

As far as a new +aquaterm option is concerned, the reason why I
suggested its addition is that removing aquaterm support is a
"quick-and-dirty" solution to make a different terminal the default
one. With working x11/qt/wxt there are a lot of options to choose
from, and there is reasonable number of people wanting to change the
default.

An alternative to "+aquaterm" is to add a patch (rejected by gnuplot
developers last time when I asked) which would enable setting the
default terminal. So instead of

    [+]aqua, [+]luaterm, (legacy) no_x11, [+]pangocairo, qt, tutorial,
universal, wxwidgets, wxwidgets_devel, [+]x11

one would end up with

    [+]default_aqua, default_x11, default_qt, default_wxt, [+]luaterm,
(legacy) no_x11, [+]pangocairo, qt, tutorial, universal, wxwidgets,
wxwidgets_devel, [+]x11

Maybe that option is better after all.

Thank you,
    Mojca