File/rc holding the defaults of whoever is running the program, read
after pce<-defaults
and therefore winning over it. The default value is the file("$PCEAPPDATA/Defaults").
@nil reads
none, which is how a program says it is not to depend on the preferences
of its user -- a test suite wants that, and so does an application that
must look the same for everyone.
pce<-defaults
is read either way: it carries the font bindings, so a program without
it would not merely lose preferences, it would look wrong.
Both are read by the first lookup of a class variable,
so this has to be set before then. From SWI-Prolog it is set by the
xpce_defaults Prolog flag, which pce_init/3
hands over while XPCE starts: a file name to read that in place of the
user's, or none to read none. swipl -Dxpce_defaults=none
is the way to say it on the command line.
A runtime application that wishes the defauts to be in the resource
file should do:
resource(pce, defaults, pce('Defaults')).
:- initialization
send(@pce, defaults, rc(pce, defaults)).
