> There is more to externalising than speed.
Agreed. And the string solution is not even slow...
> ...
> You would have done better to argue for a strstream solution in your
> original proposal so we could just add a strstream operator<< and
> operator>> for data objects like PrinterParams etc.
Well, using strings means using stringstreams for conversion. I was not
arguing for anything else. Maybe a year ago I'd have used strstreams,
but that's solved now... I am growing up, too.
> or delete a variable from the data structure. We could add the type_info
> within the operator<< like this to get some extra checking (assuming my
> imagined stream operators exist) or just use a string name:
>
> stringstream & operator<< (stringstream & ss, PrinterParams const & pp)
^^^^^^^^^^^^ this should work with any ostream.
> {
> // can we export type_info to a stream?
> return ss << type_info(pp) ...
This is possible but not acceptable for anything external since type_info
can/will depend on compiler and platform.
I can see, however, no problem with your alternative 'a string name' as in
return ss << "printerparam " << ...
> stringstream & operator>> (stringstream & ss, PrinterParams & pp)
> {
> Assert (ss[0] == type_info(pp))
> // how do you extract the type_info from a stream?
If you pass strings around instead of streams, you simply check the first
"word" in the string. Streams are inherently write/read once, everything
else is a kludge.
Another option to uniformaly pass complex information around is some data
structure that resembles XML, i.e.
struct info
{
string name_; // "printerparam"
map<string, string> parameters_; // "target"->"..", "duplex"->"1"...
string contents_; // empty in this case
vector<string> nested_; // empty in this case
}
with content similar to lyxtext, i.e. "normal text" with a special marker
for the nested elements (aka "LyX Insets"). This can be made pretty
fast, I use variations of this in Real Live (i.e. the programming I do to
earn a living). In the context of a heavy user interface (like LyX) it is
not even noticable.
Andre'
> P.S. I see you wrote this on Friday so I guess I've taken your flame bait
It was just a small bait, but the time was certainly right ;-)
I am much more relaxed about LyX development nowadays than I was some
time ago. Maybe this is because I haven't used LyX much lately, so I can
consider looking at the sources as a mere hobby and not as "fixing a tool I
desperately need for work". Or, maybe it is because I see progress in a
direction that I like. I don't really know...
--
Andre' Poenitz ........................................ [EMAIL PROTECTED]
