argument:
setlistener(<property>, <func> [, <initial=0> [, <persistent=1>]])
This definition defaults to the old behavior. The fourth argument can
be set to zero, in which case the function is only called when the
node value has actually changed. It should really default to zero, but
then all callers would have to be reviewed, which is a bit too dangerous
"shortly" before a release.
0 -> trigger whenever property is written to (even if it's the old value; default)
1 -> like 0, but also trigger the function initially
2 -> trigger initially, but then only on changes
parser. Advantages over xml.nas: (reviewed and OK'ed by Andy)
- faster (33% ... only. I had hoped for more.)
- more standards compliant
- should support UTF
- I don't have to support it. ;-)
Usage: parsexml(<path> [, <start-tag> [, <end-tag> [, <data> [, <pi>]]]]);
<path> is an absolute file path, the rest are optional callback functions.
Example:
parsexml("/tmp/foo.xml", nil, nil, func(d) { print("DATA FOUND: ", d) });
their XML wrapper/animation file. They can access their /ai/models node
via cmdarg() function. Example:
<nasal>
<load>
print("Hi, I'm the Nimitz. My data are under ",
cmdarg().getPath());
</load>
<unload>
...
</unload>
</nasal>
Note, however, that the <unload> block is only called on exit at the moment,
not when the tile is unloaded.
maintainable. The rules are simple (extension functions are called
*with* the lock, which must be dropped before calling naCall(), which
grabs it) but the tracking of when the lock was held was getting a
little confused. Keep a "nasal call depth" count in the subsystem to
figure out whether we are making a sub-call and thus hold the lock.
SGPropertyNode to guarded ones. This is also done for JSBSim/JSBSim.hxx,
for which JSB had given explicit permission a while ago. I postponed that
back then, but now is the time.
used in dialog.cxx to allow XML dialogs access to their own prop tree via
Nasal's cmdarg(). That way dialogs can generate dynamic content, such as
list entries.
implement FGNasalModelData class for execution of XML <load> and <unload>
scripts. modelLoaded() is called by the model loader, and the destructor
on branch removal.
modelmgr.cxx:
tilemgr.cxx:
tileentry.[ch]xx:
make scenery and custom objects run their Nasal scripts on loading
and unloading. Let OBJECT_STATIC object not be cached.
or write to the color properties in /sim/screen/. If this Nasal/GUI
implementation turns out to be too slow, we'll write a generic OpenGL/plib
version simliar to the ATCdisplay code. (OK'ed by Andy and Stuart)
- Provide a Nasal interface to display simple text messages on the screen
like the ATC display. In fact, I copied the code from the ATCDisplay.cxx
and simply shifted it further down the screen.
Erik:
TODO: Integrate the two pieces of code.
replaced with efficient listener callbacks. One use is the new FPS display.
This is reviewed and OK'ed by Andy, relatively trivial and separated from
the rest of Nasal, so problems are quite unlikely and confined to users of
this function.
The callback is executed whenever the property is written to -- even if
the value didn't change. The triggering Node is available via cmdarg().
Examples: _setlistener("/sim/crashed", func {print("haha!")});
_setlistener("/foo/bar", func { print(cmdarg().getPath() ~ " changed")})
- make it public
- enable handleCommand() to execute a binding (or other nasal code defined
in a property system subtree) in a particular namespace (-> "module" child)
interface, and use it to cache FGNasalScript objects returned from
a new parseScript() method.
Added a rand() function.
Added an interpolate() function interface to the new SGInterpolator
subsystem.
