X-Git-Url: https://git.mxchange.org/?a=blobdiff_plain;f=src%2FScripting%2FNasalSys.cxx;h=75c49fbcf5d05d7b262b1de836e01ba9d21569d9;hb=4b59c152eafb5aa52c4562838090f037c07b65e9;hp=0134dcb264ee1a621fb324c26f4e7353add2857e;hpb=b82ea065c34c6ab4f13c76ec481d7ae37caab8b3;p=flightgear.git

diff --git a/src/Scripting/NasalSys.cxx b/src/Scripting/NasalSys.cxx
index 0134dcb26..75c49fbcf 100644
--- a/src/Scripting/NasalSys.cxx
+++ b/src/Scripting/NasalSys.cxx
@@ -3,6 +3,10 @@
 #  include "config.h"
 #endif
 
+#ifdef HAVE_WINDOWS_H
+#include <windows.h>
+#endif
+
 #ifdef HAVE_SYS_TIME_H
 #  include <sys/time.h>  // gettimeofday
 #endif
@@ -19,23 +23,38 @@
 #include <simgear/math/sg_random.h>
 #include <simgear/misc/sg_path.hxx>
 #include <simgear/misc/sg_dir.hxx>
-#include <simgear/misc/interpolator.hxx>
-#include <simgear/scene/material/mat.hxx>
+#include <simgear/misc/SimpleMarkdown.hxx>
 #include <simgear/structure/commands.hxx>
 #include <simgear/math/sg_geodesy.hxx>
 #include <simgear/structure/event_mgr.hxx>
+#include <simgear/debug/BufferedLogCallback.hxx>
+
+#include <simgear/nasal/cppbind/from_nasal.hxx>
+#include <simgear/nasal/cppbind/to_nasal.hxx>
+#include <simgear/nasal/cppbind/Ghost.hxx>
+#include <simgear/nasal/cppbind/NasalHash.hxx>
+
+#include "NasalSGPath.hxx"
+#include "NasalSys.hxx"
+#include "NasalSys_private.hxx"
+#include "NasalAircraft.hxx"
+#include "NasalModelData.hxx"
+#include "NasalPositioned.hxx"
+#include "NasalCanvas.hxx"
+#include "NasalClipboard.hxx"
+#include "NasalCondition.hxx"
+#include "NasalHTTP.hxx"
+#include "NasalString.hxx"
 
-#include <Airports/runways.hxx>
-#include <Airports/simple.hxx>
 #include <Main/globals.hxx>
-#include <Main/fg_props.hxx>
 #include <Main/util.hxx>
-#include <Scenery/scenery.hxx>
-#include <Navaids/navlist.hxx>
-#include <Navaids/procedure.hxx>
+#include <Main/fg_props.hxx>
 
+using std::map;
+using std::string;
+using std::vector;
 
-#include "NasalSys.hxx"
+void postinitNasalGUI(naRef globals, naContext c);
 
 static FGNasalSys* nasalSys = 0;
 
@@ -64,6 +83,100 @@ void FGNasalModuleListener::valueChanged(SGPropertyNode*)
     }
 }
 
+//////////////////////////////////////////////////////////////////////////
+
+
+class TimerObj : public SGReferenced
+{
+public:
+  TimerObj(FGNasalSys* sys, naRef f, naRef self, double interval) :
+    _sys(sys),
+    _func(f),
+    _self(self),
+    _isRunning(false),
+    _interval(interval),
+    _singleShot(false)
+  {
+    char nm[128];
+    snprintf(nm, 128, "nasal-timer-%p", this);
+    _name = nm;
+    _gcRoot =  sys->gcSave(f);
+    _gcSelf = sys->gcSave(self);
+  }
+  
+  virtual ~TimerObj()
+  {
+    stop();
+    _sys->gcRelease(_gcRoot);
+    _sys->gcRelease(_gcSelf);
+  }
+  
+  bool isRunning() const { return _isRunning; }
+    
+  void stop()
+  {
+    if (_isRunning) {
+      globals->get_event_mgr()->removeTask(_name);
+      _isRunning = false;
+    }
+  }
+  
+  void start()
+  {
+    if (_isRunning) {
+      return;
+    }
+    
+    _isRunning = true;
+    if (_singleShot) {
+      globals->get_event_mgr()->addEvent(_name, this, &TimerObj::invoke, _interval);
+    } else {
+      globals->get_event_mgr()->addTask(_name, this, &TimerObj::invoke,
+                                        _interval, _interval /* delay */);
+    }
+  }
+  
+  // stop and then start -
+  void restart(double newInterval)
+  {
+    _interval = newInterval;
+    stop();
+    start();
+  }
+  
+  void invoke()
+  {
+    if( _singleShot )
+      // Callback may restart the timer, so update status before callback is
+      // called (Prevent warnings of deleting not existing tasks from the
+      // event manager).
+      _isRunning = false;
+
+    naRef *args = NULL;
+    _sys->callMethod(_func, _self, 0, args, naNil() /* locals */);
+  }
+  
+  void setSingleShot(bool aSingleShot)
+  {
+    _singleShot = aSingleShot;
+  }
+  
+  bool isSingleShot() const
+  { return _singleShot; }
+private:
+  std::string _name;
+  FGNasalSys* _sys;
+  naRef _func, _self;
+  int _gcRoot, _gcSelf;
+  bool _isRunning;
+  double _interval;
+  bool _singleShot;
+};
+
+typedef SGSharedPtr<TimerObj> TimerObjRef;
+typedef nasal::Ghost<TimerObjRef> NasalTimerObj;
+
+///////////////////////////////////////////////////////////////////////////
 
 // Read and return file contents in a single buffer.  Note use of
 // stat() to get the file size.  This is a win32 function, believe it
@@ -93,14 +206,44 @@ static char* readfile(const char* file, int* lenOut)
     return buf;
 }
 
-FGNasalSys::FGNasalSys()
+FGNasalSys::FGNasalSys() :
+    _inited(false)
 {
     nasalSys = this;
     _context = 0;
     _globals = naNil();
-    _gcHash = naNil();
-    _nextGCKey = 0; // Any value will do
-    _callCount = 0;
+    _string = naNil();
+    _wrappedNodeFunc = naNil();
+    
+    _log = new simgear::BufferedLogCallback(SG_NASAL, SG_INFO);
+    _log->truncateAt(255);
+    sglog().addCallback(_log);
+
+    naSetErrorHandler(&logError);
+}
+
+// Utility.  Sets a named key in a hash by C string, rather than nasal
+// string object.
+void FGNasalSys::hashset(naRef hash, const char* key, naRef val)
+{
+    naRef s = naNewString(_context);
+    naStr_fromdata(s, (char*)key, strlen(key));
+    naHash_set(hash, s, val);
+}
+
+void FGNasalSys::globalsSet(const char* key, naRef val)
+{
+  hashset(_globals, key, val);
+}
+
+naRef FGNasalSys::call(naRef code, int argc, naRef* args, naRef locals)
+{
+  return callMethod(code, naNil(), argc, args, locals);
+}
+
+naRef FGNasalSys::callWithContext(naContext ctx, naRef code, int argc, naRef* args, naRef locals)
+{
+  return callMethodWithContext(ctx, code, naNil(), argc, args, locals);
 }
 
 // Does a naCall() in a new context.  Wrapped here to make lock
@@ -109,41 +252,40 @@ FGNasalSys::FGNasalSys()
 // drop the lock in every extension function that might call back into
 // Nasal, we keep a stack depth counter here and only unlock/lock
 // around the naCall if it isn't the first one.
-naRef FGNasalSys::call(naRef code, int argc, naRef* args, naRef locals)
+
+naRef FGNasalSys::callMethod(naRef code, naRef self, int argc, naRef* args, naRef locals)
 {
-    naContext ctx = naNewContext();
-    if(_callCount) naModUnlock();
-    _callCount++;
-    naRef result = naCall(ctx, code, argc, args, naNil(), locals);
-    if(naGetError(ctx))
-        logError(ctx);
-    _callCount--;
-    if(_callCount) naModLock();
-    naFreeContext(ctx);
-    return result;
+  return naCallMethod(code, self, argc, args, locals);
+}
+
+naRef FGNasalSys::callMethodWithContext(naContext ctx, naRef code, naRef self, int argc, naRef* args, naRef locals)
+{
+  return naCallMethodCtx(ctx, code, self, argc, args, locals);
 }
 
 FGNasalSys::~FGNasalSys()
 {
+    if (_inited) {
+        SG_LOG(SG_GENERAL, SG_ALERT, "Nasal was not shutdown");
+    }
     nasalSys = 0;
-    map<int, FGNasalListener *>::iterator it, end = _listener.end();
-    for(it = _listener.begin(); it != end; ++it)
-        delete it->second;
-
-    naFreeContext(_context);
-    _globals = naNil();
 }
 
 bool FGNasalSys::parseAndRun(const char* sourceCode)
 {
-    naRef code = parse("FGNasalSys::parseAndRun()", sourceCode,
+    naContext ctx = naNewContext();
+    naRef code = parse(ctx, "FGNasalSys::parseAndRun()", sourceCode,
                        strlen(sourceCode));
-    if(naIsNil(code))
+    if(naIsNil(code)) {
+        naFreeContext(ctx);
         return false;
-    call(code, 0, 0, naNil());
+    }
+    callWithContext(ctx, code, 0, 0, naNil());
+    naFreeContext(ctx);
     return true;
 }
 
+#if 0
 FGNasalScript* FGNasalSys::parseScript(const char* src, const char* name)
 {
     FGNasalScript* script = new FGNasalScript();
@@ -165,36 +307,33 @@ FGNasalScript* FGNasalSys::parseScript(const char* src, const char* name)
     script->_gcKey = gcSave(script->_code);
     return script;
 }
-
-// Utility.  Sets a named key in a hash by C string, rather than nasal
-// string object.
-void FGNasalSys::hashset(naRef hash, const char* key, naRef val)
-{
-    naRef s = naNewString(_context);
-    naStr_fromdata(s, (char*)key, strlen(key));
-    naHash_set(hash, s, val);
-}
+#endif
 
 // The get/setprop functions accept a *list* of strings and walk
 // through the property tree with them to find the appropriate node.
 // This allows a Nasal object to hold onto a property path and use it
 // like a node object, e.g. setprop(ObjRoot, "size-parsecs", 2.02).  This
 // is the utility function that walks the property tree.
-// Future enhancement: support integer arguments to specify array
-// elements.
-static SGPropertyNode* findnode(naContext c, naRef* vec, int len)
+static SGPropertyNode* findnode(naContext c, naRef* vec, int len, bool create=false)
 {
     SGPropertyNode* p = globals->get_props();
     try {
         for(int i=0; i<len; i++) {
             naRef a = vec[i];
-            if(!naIsString(a)) return 0;
-            p = p->getNode(naStr_data(a));
+            if(!naIsString(a)) {
+                naRuntimeError(c, "bad argument to setprop/getprop path: expected a string");
+            }
+            naRef b = i < len-1 ? naNumValue(vec[i+1]) : naNil();
+            if (!naIsNil(b)) {
+                p = p->getNode(naStr_data(a), (int)b.num, create);
+                i++;
+            } else {
+                p = p->getNode(naStr_data(a), create);
+            }
             if(p == 0) return 0;
         }
     } catch (const string& err) {
         naRuntimeError(c, (char *)err.c_str());
-        return 0;
     }
     return p;
 }
@@ -205,7 +344,10 @@ static SGPropertyNode* findnode(naContext c, naRef* vec, int len)
 static naRef f_getprop(naContext c, naRef me, int argc, naRef* args)
 {
     using namespace simgear;
-    const SGPropertyNode* p = findnode(c, args, argc);
+    if (argc < 1) {
+        naRuntimeError(c, "getprop() expects at least 1 argument");
+    }
+    const SGPropertyNode* p = findnode(c, args, argc, false);
     if(!p) return naNil();
 
     switch(p->getType()) {
@@ -214,8 +356,8 @@ static naRef f_getprop(naContext c, naRef me, int argc, naRef* args)
     case props::DOUBLE:
         {
         double dv = p->getDoubleValue();
-        if (osg::isNaN(dv)) {
-          SG_LOG(SG_GENERAL, SG_ALERT, "Nasal getprop: property " << p->getPath() << " is NaN");
+        if (SGMisc<double>::isNaN(dv)) {
+          SG_LOG(SG_NASAL, SG_ALERT, "Nasal getprop: property " << p->getPath() << " is NaN");
           return naNil();
         }
         
@@ -241,45 +383,29 @@ static naRef f_getprop(naContext c, naRef me, int argc, naRef* args)
 // final argument.
 static naRef f_setprop(naContext c, naRef me, int argc, naRef* args)
 {
-#define BUFLEN 1024
-    char buf[BUFLEN + 1];
-    buf[BUFLEN] = 0;
-    char* p = buf;
-    int buflen = BUFLEN;
-    if(argc < 2) naRuntimeError(c, "setprop() expects at least 2 arguments");
-    for(int i=0; i<argc-1; i++) {
-        naRef s = naStringValue(c, args[i]);
-        if(naIsNil(s)) return naNil();
-        strncpy(p, naStr_data(s), buflen);
-        p += naStr_len(s);
-        buflen = BUFLEN - (p - buf);
-        if(i < (argc-2) && buflen > 0) {
-            *p++ = '/';
-            buflen--;
-        }
+    if (argc < 2) {
+        naRuntimeError(c, "setprop() expects at least 2 arguments");
     }
+    naRef val = args[argc - 1];
+    SGPropertyNode* p = findnode(c, args, argc-1, true);
 
-    SGPropertyNode* props = globals->get_props();
-    naRef val = args[argc-1];
     bool result = false;
     try {
-        if(naIsString(val)) result = props->setStringValue(buf, naStr_data(val));
+        if(naIsString(val)) result = p->setStringValue(naStr_data(val));
         else {
-            naRef n = naNumValue(val);
-            if(naIsNil(n))
+            if(!naIsNum(val))
                 naRuntimeError(c, "setprop() value is not string or number");
                 
-            if (osg::isNaN(n.num)) {
+            if (SGMisc<double>::isNaN(val.num)) {
                 naRuntimeError(c, "setprop() passed a NaN");
             }
             
-            result = props->setDoubleValue(buf, n.num);
+            result = p->setDoubleValue(val.num);
         }
     } catch (const string& err) {
         naRuntimeError(c, (char *)err.c_str());
     }
     return naNum(result);
-#undef BUFLEN
 }
 
 // print() extension function.  Concatenates and prints its arguments
@@ -294,10 +420,35 @@ static naRef f_print(naContext c, naRef me, int argc, naRef* args)
         if(naIsNil(s)) continue;
         buf += naStr_data(s);
     }
-    SG_LOG(SG_GENERAL, SG_ALERT, buf);
+    SG_LOG(SG_NASAL, SG_ALERT, buf);
     return naNum(buf.length());
 }
 
+// logprint() extension function.  Same as above, all arguments after the
+// first argument are concatenated. Argument 0 is the log-level, matching
+// sgDebugPriority.
+static naRef f_logprint(naContext c, naRef me, int argc, naRef* args)
+{
+  if (argc < 1)
+    naRuntimeError(c, "no prioirty argument to logprint()");
+  
+  naRef priority = args[0];
+  string buf;
+  int n = argc;
+  for(int i=1; i<n; i++) {
+    naRef s = naStringValue(c, args[i]);
+    if(naIsNil(s)) continue;
+    buf += naStr_data(s);
+  }
+// use the nasal source file and line for the message location, since
+// that's more useful than the location here!
+  sglog().log(SG_NASAL, (sgDebugPriority)(int) priority.num,
+               naStr_data(naGetSourceFile(c, 0)),
+               naGetLine(c, 0), buf);
+  return naNum(buf.length());
+}
+
+
 // fgcommand() extension function.  Executes a named command via the
 // FlightGear command manager.  Takes a single property node name as
 // an argument.
@@ -325,6 +476,24 @@ static naRef f_settimer(naContext c, naRef me, int argc, naRef* args)
     return naNil();
 }
 
+static naRef f_makeTimer(naContext c, naRef me, int argc, naRef* args)
+{
+  if (!naIsNum(args[0])) {
+    naRuntimeError(c, "bad interval argument to maketimer");
+  }
+    
+  naRef func, self = naNil();
+  if (naIsFunc(args[1])) {
+    func = args[1];
+  } else if ((argc == 3) && naIsFunc(args[2])) {
+    self = args[1];
+    func = args[2];
+  }
+  
+  TimerObj* timerObj = new TimerObj(nasalSys, func, self, args[0].num);
+  return nasal::to_nasal(c, timerObj);
+}
+
 // setlistener(func, property, bool) extension function.  Falls through to
 // FGNasalSys::setListener().  See there for docs.
 static naRef f_setlistener(naContext c, naRef me, int argc, naRef* args)
@@ -352,29 +521,31 @@ static naRef f_cmdarg(naContext c, naRef me, int argc, naRef* args)
 // value/delta numbers.
 static naRef f_interpolate(naContext c, naRef me, int argc, naRef* args)
 {
-    SGPropertyNode* node;
-    naRef prop = argc > 0 ? args[0] : naNil();
-    if(naIsString(prop)) node = fgGetNode(naStr_data(prop), true);
-    else if(naIsGhost(prop)) node = *(SGPropertyNode_ptr*)naGhost_ptr(prop);
-    else return naNil();
-
-    naRef curve = argc > 1 ? args[1] : naNil();
-    if(!naIsVector(curve)) return naNil();
-    int nPoints = naVec_size(curve) / 2;
-    double* values = new double[nPoints];
-    double* deltas = new double[nPoints];
-    for(int i=0; i<nPoints; i++) {
-        values[i] = naNumValue(naVec_get(curve, 2*i)).num;
-        deltas[i] = naNumValue(naVec_get(curve, 2*i+1)).num;
-    }
+  SGPropertyNode* node;
+  naRef prop = argc > 0 ? args[0] : naNil();
+  if(naIsString(prop)) node = fgGetNode(naStr_data(prop), true);
+  else if(naIsGhost(prop)) node = *(SGPropertyNode_ptr*)naGhost_ptr(prop);
+  else return naNil();
 
-    ((SGInterpolator*)globals->get_subsystem_mgr()
-        ->get_group(SGSubsystemMgr::INIT)->get_subsystem("interpolator"))
-        ->interpolate(node, nPoints, values, deltas);
+  naRef curve = argc > 1 ? args[1] : naNil();
+  if(!naIsVector(curve)) return naNil();
+  int nPoints = naVec_size(curve) / 2;
 
-    delete[] values;
-    delete[] deltas;
-    return naNil();
+  simgear::PropertyList value_nodes;
+  value_nodes.reserve(nPoints);
+  double_list deltas;
+  deltas.reserve(nPoints);
+
+  for( int i = 0; i < nPoints; ++i )
+  {
+    SGPropertyNode* val = new SGPropertyNode;
+    val->setDoubleValue(naNumValue(naVec_get(curve, 2*i)).num);
+    value_nodes.push_back(val);
+    deltas.push_back(naNumValue(naVec_get(curve, 2*i+1)).num);
+  }
+
+  node->interpolate("numeric", value_nodes, deltas, "linear");
+  return naNil();
 }
 
 // This is a better RNG than the one in the default Nasal distribution
@@ -429,6 +600,69 @@ static naRef f_resolveDataPath(naContext c, naRef me, int argc, naRef* args)
     return naStr_fromdata(naNewString(c), const_cast<char*>(pdata), strlen(pdata));
 }
 
+static naRef f_findDataDir(naContext c, naRef me, int argc, naRef* args)
+{
+    if(argc != 1 || !naIsString(args[0]))
+        naRuntimeError(c, "bad arguments to findDataDir()");
+    
+    SGPath p = globals->find_data_dir(naStr_data(args[0]));
+    const char* pdata = p.c_str();
+    return naStr_fromdata(naNewString(c), const_cast<char*>(pdata), strlen(pdata));
+}
+
+class NasalCommand : public SGCommandMgr::Command
+{
+public:
+    NasalCommand(FGNasalSys* sys, naRef f, const std::string& name) :
+        _sys(sys),
+        _func(f),
+        _name(name)
+    {
+        globals->get_commands()->addCommandObject(_name, this);
+        _gcRoot =  sys->gcSave(f);
+    }
+    
+    virtual ~NasalCommand()
+    {
+        _sys->gcRelease(_gcRoot);
+    }
+    
+    virtual bool operator()(const SGPropertyNode* aNode)
+    {
+        _sys->setCmdArg(const_cast<SGPropertyNode*>(aNode));
+        naRef args[1];
+        args[0] = _sys->wrappedPropsNode(const_cast<SGPropertyNode*>(aNode));
+    
+        _sys->callMethod(_func, naNil(), 1, args, naNil() /* locals */);
+
+        return true;
+    }
+    
+private:
+    FGNasalSys* _sys;
+    naRef _func;
+    int _gcRoot;
+    std::string _name;
+};
+
+static naRef f_addCommand(naContext c, naRef me, int argc, naRef* args)
+{
+    if(argc != 2 || !naIsString(args[0]) || !naIsFunc(args[1]))
+        naRuntimeError(c, "bad arguments to addcommand()");
+    
+    nasalSys->addCommand(args[1], naStr_data(args[0]));
+    return naNil();
+}
+
+static naRef f_removeCommand(naContext c, naRef me, int argc, naRef* args)
+{
+    if ((argc < 1) || !naIsString(args[0]))
+        naRuntimeError(c, "bad argument to removecommand()");
+    
+    globals->get_commands()->removeCommand(naStr_data(args[0]));
+    return naNil();
+}
+
 // Parse XML file.
 //     parsexml(<path> [, <start-tag> [, <end-tag> [, <data> [, <pi>]]]]);
 //
@@ -467,6 +701,35 @@ static naRef f_parsexml(naContext c, naRef me, int argc, naRef* args)
     return naStr_fromdata(naNewString(c), const_cast<char*>(file), strlen(file));
 }
 
+/**
+ * Parse very simple and small subset of markdown
+ *
+ * parse_markdown(src)
+ */
+static naRef f_parse_markdown(naContext c, naRef me, int argc, naRef* args)
+{
+  nasal::CallContext ctx(c, me, argc, args);
+  return ctx.to_nasal(
+    simgear::SimpleMarkdown::parse(ctx.requireArg<std::string>(0))
+  );
+}
+
+/**
+ * Create md5 hash from given string
+ *
+ * md5(str)
+ */
+static naRef f_md5(naContext c, naRef me, int argc, naRef* args)
+{
+  if( argc != 1 || !naIsString(args[0]) )
+    naRuntimeError(c, "md5(): wrong type or number of arguments");
+
+  return nasal::to_nasal(
+    c,
+    simgear::strutils::md5(naStr_data(args[0]), naStr_len(args[0]))
+  );
+}
+
 // Return UNIX epoch time in seconds.
 static naRef f_systime(naContext c, naRef me, int argc, naRef* args)
 {
@@ -483,314 +746,19 @@ static naRef f_systime(naContext c, naRef me, int argc, naRef* args)
 #endif
 }
 
-// Convert a cartesian point to a geodetic lat/lon/altitude.
-static naRef f_carttogeod(naContext c, naRef me, int argc, naRef* args)
-{
-    double lat, lon, alt, xyz[3];
-    if(argc != 3) naRuntimeError(c, "carttogeod() expects 3 arguments");
-    for(int i=0; i<3; i++)
-        xyz[i] = naNumValue(args[i]).num;
-    sgCartToGeod(xyz, &lat, &lon, &alt);
-    lat *= SG_RADIANS_TO_DEGREES;
-    lon *= SG_RADIANS_TO_DEGREES;
-    naRef vec = naNewVector(c);
-    naVec_append(vec, naNum(lat));
-    naVec_append(vec, naNum(lon));
-    naVec_append(vec, naNum(alt));
-    return vec;
-}
-
-// Convert a geodetic lat/lon/altitude to a cartesian point.
-static naRef f_geodtocart(naContext c, naRef me, int argc, naRef* args)
-{
-    if(argc != 3) naRuntimeError(c, "geodtocart() expects 3 arguments");
-    double lat = naNumValue(args[0]).num * SG_DEGREES_TO_RADIANS;
-    double lon = naNumValue(args[1]).num * SG_DEGREES_TO_RADIANS;
-    double alt = naNumValue(args[2]).num;
-    double xyz[3];
-    sgGeodToCart(lat, lon, alt, xyz);
-    naRef vec = naNewVector(c);
-    naVec_append(vec, naNum(xyz[0]));
-    naVec_append(vec, naNum(xyz[1]));
-    naVec_append(vec, naNum(xyz[2]));
-    return vec;
-}
-
-// For given geodetic point return array with elevation, and a material data
-// hash, or nil if there's no information available (tile not loaded). If
-// information about the material isn't available, then nil is returned instead
-// of the hash.
-static naRef f_geodinfo(naContext c, naRef me, int argc, naRef* args)
-{
-#define HASHSET(s,l,n) naHash_set(matdata, naStr_fromdata(naNewString(c),s,l),n)
-    if(argc < 2 || argc > 3)
-        naRuntimeError(c, "geodinfo() expects 2 or 3 arguments: lat, lon [, maxalt]");
-    double lat = naNumValue(args[0]).num;
-    double lon = naNumValue(args[1]).num;
-    double elev = argc == 3 ? naNumValue(args[2]).num : 10000;
-    const SGMaterial *mat;
-    SGGeod geod = SGGeod::fromDegM(lon, lat, elev);
-    if(!globals->get_scenery()->get_elevation_m(geod, elev, &mat))
-        return naNil();
-    naRef vec = naNewVector(c);
-    naVec_append(vec, naNum(elev));
-    naRef matdata = naNil();
-    if(mat) {
-        matdata = naNewHash(c);
-        naRef names = naNewVector(c);
-        const vector<string> n = mat->get_names();
-        for(unsigned int i=0; i<n.size(); i++)
-            naVec_append(names, naStr_fromdata(naNewString(c),
-                    const_cast<char*>(n[i].c_str()), n[i].size()));
-        HASHSET("names", 5, names);
-        HASHSET("solid", 5, naNum(mat->get_solid()));
-        HASHSET("friction_factor", 15, naNum(mat->get_friction_factor()));
-        HASHSET("rolling_friction", 16, naNum(mat->get_rolling_friction()));
-        HASHSET("load_resistance", 15, naNum(mat->get_load_resistance()));
-        HASHSET("bumpiness", 9, naNum(mat->get_bumpiness()));
-        HASHSET("light_coverage", 14, naNum(mat->get_light_coverage()));
-    }
-    naVec_append(vec, matdata);
-    return vec;
-#undef HASHSET
-}
-
-
-class AirportInfoFilter : public FGAirport::AirportFilter
-{
-public:
-    AirportInfoFilter() : type(FGPositioned::AIRPORT) {
-    }
-
-    virtual FGPositioned::Type minType() const {
-        return type;
-    }
-
-    virtual FGPositioned::Type maxType() const {
-        return type;
-    }
-
-    FGPositioned::Type type;
-};
-
-// Returns data hash for particular or nearest airport of a <type>, or nil
-// on error.
-//
-// airportinfo(<id>);                   e.g. "KSFO"
-// airportinfo(<type>);                 type := ("airport"|"seaport"|"heliport")
-// airportinfo()                        same as  airportinfo("airport")
-// airportinfo(<lat>, <lon> [, <type>]);
-static naRef f_airportinfo(naContext c, naRef me, int argc, naRef* args)
-{
-    static SGConstPropertyNode_ptr latn = fgGetNode("/position/latitude-deg", true);
-    static SGConstPropertyNode_ptr lonn = fgGetNode("/position/longitude-deg", true);
-    SGGeod pos;
-    FGAirport* apt = NULL;
-
-    if(argc >= 2 && naIsNum(args[0]) && naIsNum(args[1])) {
-        pos = SGGeod::fromDeg(args[1].num, args[0].num);
-        args += 2;
-        argc -= 2;
-    } else {
-        pos = SGGeod::fromDeg(lonn->getDoubleValue(), latn->getDoubleValue());
-    }
-
-    double maxRange = 10000.0; // expose this? or pick a smaller value?
-
-    AirportInfoFilter filter; // defaults to airports only
-
-    if(argc == 0) {
-        // fall through and use AIRPORT
-    } else if(argc == 1 && naIsString(args[0])) {
-        const char *s = naStr_data(args[0]);
-        if(!strcmp(s, "airport")) filter.type = FGPositioned::AIRPORT;
-        else if(!strcmp(s, "seaport")) filter.type = FGPositioned::SEAPORT;
-        else if(!strcmp(s, "heliport")) filter.type = FGPositioned::HELIPORT;
-        else {
-            // user provided an <id>, hopefully
-            apt = FGAirport::findByIdent(s);
-            if (!apt) {
-                // return nil here, but don't raise a runtime error; this is a
-                // legitamate way to validate an ICAO code, for example in a
-                // dialog box or similar.
-                return naNil();
-            }
-        }
-    } else {
-        naRuntimeError(c, "airportinfo() with invalid function arguments");
-        return naNil();
-    }
-
-    if(!apt) {
-        apt = FGAirport::findClosest(pos, maxRange, &filter);
-        if(!apt) return naNil();
-    }
-
-    string id = apt->ident();
-    string name = apt->name();
-
-    // set runway hash
-    naRef rwys = naNewHash(c);
-    for(unsigned int r=0; r<apt->numRunways(); ++r) {
-        FGRunway* rwy(apt->getRunwayByIndex(r));
-
-        naRef rwyid = naStr_fromdata(naNewString(c),
-                      const_cast<char *>(rwy->ident().c_str()),
-                      rwy->ident().length());
-
-        naRef rwydata = naNewHash(c);
-#define HASHSET(s,l,n) naHash_set(rwydata, naStr_fromdata(naNewString(c),s,l),n)
-        HASHSET("id", 2, rwyid);
-        HASHSET("lat", 3, naNum(rwy->latitude()));
-        HASHSET("lon", 3, naNum(rwy->longitude()));
-        HASHSET("heading", 7, naNum(rwy->headingDeg()));
-        HASHSET("length", 6, naNum(rwy->lengthM()));
-        HASHSET("width", 5, naNum(rwy->widthM()));
-        HASHSET("threshold", 9, naNum(rwy->displacedThresholdM()));
-        HASHSET("stopway", 7, naNum(rwy->stopwayM()));
-        
-        if (rwy->ILS()) {
-          HASHSET("ils_frequency_mhz", 17, naNum(rwy->ILS()->get_freq() / 100.0));
-        }
-        
-        std::vector<flightgear::SID*> sids(rwy->getSIDs());
-        naRef sidVec = naNewVector(c);
-        
-        for (unsigned int s=0; s < sids.size(); ++s) {
-          naRef procId = naStr_fromdata(naNewString(c),
-                    const_cast<char *>(sids[s]->ident().c_str()),
-                    sids[s]->ident().length());
-          naVec_append(sidVec, procId);
-        }
-        HASHSET("sids", 4, sidVec); 
-        
-        std::vector<flightgear::STAR*> stars(rwy->getSTARs());
-        naRef starVec = naNewVector(c);
-      
-        for (unsigned int s=0; s < stars.size(); ++s) {
-          naRef procId = naStr_fromdata(naNewString(c),
-                    const_cast<char *>(stars[s]->ident().c_str()),
-                    stars[s]->ident().length());
-          naVec_append(starVec, procId);
-        }
-        HASHSET("stars", 5, starVec); 
-
-#undef HASHSET
-        naHash_set(rwys, rwyid, rwydata);
-    }
-
-    // set airport hash
-    naRef aptdata = naNewHash(c);
-#define HASHSET(s,l,n) naHash_set(aptdata, naStr_fromdata(naNewString(c),s,l),n)
-    HASHSET("id", 2, naStr_fromdata(naNewString(c),
-            const_cast<char *>(id.c_str()), id.length()));
-    HASHSET("name", 4, naStr_fromdata(naNewString(c),
-            const_cast<char *>(name.c_str()), name.length()));
-    HASHSET("lat", 3, naNum(apt->getLatitude()));
-    HASHSET("lon", 3, naNum(apt->getLongitude()));
-    HASHSET("elevation", 9, naNum(apt->getElevation() * SG_FEET_TO_METER));
-    HASHSET("has_metar", 9, naNum(apt->getMetar()));
-    HASHSET("runways", 7, rwys);
-#undef HASHSET
-    return aptdata;
-}
-
-
-// Returns vector of data hash for navaid of a <type>, nil on error
-// navaids sorted by ascending distance 
-// navinfo([<lat>,<lon>],[<type>],[<id>])
-// lat/lon (numeric): use latitude/longitude instead of ac position
-// type:              ("fix"|"vor"|"ndb"|"ils"|"dme"|"tacan"|"any")
-// id:                (partial) id of the fix
-// examples:
-// navinfo("vor")     returns all vors
-// navinfo("HAM")     return all navaids who's name start with "HAM"
-// navinfo("vor", "HAM") return all vor who's name start with "HAM"
-//navinfo(34,48,"vor","HAM") return all vor who's name start with "HAM" 
-//                           sorted by distance relative to lat=34, lon=48
-static naRef f_navinfo(naContext c, naRef me, int argc, naRef* args)
-{
-    static SGConstPropertyNode_ptr latn = fgGetNode("/position/latitude-deg", true);
-    static SGConstPropertyNode_ptr lonn = fgGetNode("/position/longitude-deg", true);
-    SGGeod pos;
-
-    if(argc >= 2 && naIsNum(args[0]) && naIsNum(args[1])) {
-        pos = SGGeod::fromDeg(args[1].num, args[0].num);
-        args += 2;
-        argc -= 2;
-    } else {
-        pos = SGGeod::fromDeg(lonn->getDoubleValue(), latn->getDoubleValue());
-    }
-
-    FGPositioned::Type type = FGPositioned::INVALID;
-    nav_list_type navlist;
-    const char * id = "";
-
-    if(argc > 0 && naIsString(args[0])) {
-        const char *s = naStr_data(args[0]);
-        if(!strcmp(s, "any")) type = FGPositioned::INVALID;
-        else if(!strcmp(s, "fix")) type = FGPositioned::FIX;
-        else if(!strcmp(s, "vor")) type = FGPositioned::VOR;
-        else if(!strcmp(s, "ndb")) type = FGPositioned::NDB;
-        else if(!strcmp(s, "ils")) type = FGPositioned::ILS;
-        else if(!strcmp(s, "dme")) type = FGPositioned::DME;
-        else if(!strcmp(s, "tacan")) type = FGPositioned::TACAN;
-        else id = s; // this is an id
-        ++args;
-        --argc;
-    } 
-
-    if(argc > 0 && naIsString(args[0])) {
-        if( *id != 0 ) {
-            naRuntimeError(c, "navinfo() called with navaid id");
-            return naNil();
-        }
-        id = naStr_data(args[0]);
-        ++args;
-        --argc;
-    }
-
-    if( argc > 0 ) {
-        naRuntimeError(c, "navinfo() called with too many arguments");
-        return naNil();
-    }
-
-    navlist = globals->get_navlist()->findByIdentAndFreq( pos, id, 0.0, type );
-
-    naRef reply = naNewVector(c);
-    for( nav_list_type::const_iterator it = navlist.begin(); it != navlist.end(); ++it ) {
-        const FGNavRecord * nav = *it;
-
-        // set navdata hash
-        naRef navdata = naNewHash(c);
-#define HASHSET(s,l,n) naHash_set(navdata, naStr_fromdata(naNewString(c),s,l),n)
-        HASHSET("id", 2, naStr_fromdata(naNewString(c),
-            const_cast<char *>(nav->ident().c_str()), nav->ident().length()));
-        HASHSET("name", 4, naStr_fromdata(naNewString(c),
-            const_cast<char *>(nav->name().c_str()), nav->name().length()));
-        HASHSET("frequency", 9, naNum(nav->get_freq()));
-        HASHSET("lat", 3, naNum(nav->get_lat()));
-        HASHSET("lon", 3, naNum(nav->get_lon()));
-        HASHSET("elevation", 9, naNum(nav->get_elev_ft() * SG_FEET_TO_METER));
-        HASHSET("type", 4, naStr_fromdata(naNewString(c),
-            const_cast<char *>(nav->nameForType(nav->type())), strlen(nav->nameForType(nav->type()))));
-        HASHSET("distance", 8, naNum(SGGeodesy::distanceNm( pos, nav->geod() ) * SG_NM_TO_METER ) );
-        HASHSET("bearing", 7, naNum(SGGeodesy::courseDeg( pos, nav->geod() ) ) );
-#undef HASHSET
-        naVec_append( reply, navdata );
-    }
-    return reply;
-}
-
 // Table of extension functions.  Terminate with zeros.
 static struct { const char* name; naCFunction func; } funcs[] = {
     { "getprop",   f_getprop },
     { "setprop",   f_setprop },
     { "print",     f_print },
+    { "logprint",  f_logprint },
     { "_fgcommand", f_fgcommand },
     { "settimer",  f_settimer },
+    { "maketimer", f_makeTimer },
     { "_setlistener", f_setlistener },
     { "removelistener", f_removelistener },
+    { "addcommand", f_addCommand },
+    { "removecommand", f_removeCommand },
     { "_cmdarg",  f_cmdarg },
     { "_interpolate",  f_interpolate },
     { "rand",  f_rand },
@@ -798,13 +766,11 @@ static struct { const char* name; naCFunction func; } funcs[] = {
     { "abort", f_abort },
     { "directory", f_directory },
     { "resolvepath", f_resolveDataPath },
+    { "finddata", f_findDataDir },
     { "parsexml", f_parsexml },
+    { "parse_markdown", f_parse_markdown },
+    { "md5", f_md5 },
     { "systime", f_systime },
-    { "carttogeod", f_carttogeod },
-    { "geodtocart", f_geodtocart },
-    { "geodinfo", f_geodinfo },
-    { "airportinfo", f_airportinfo },
-    { "navinfo", f_navinfo },
     { 0, 0 }
 };
 
@@ -813,8 +779,16 @@ naRef FGNasalSys::cmdArgGhost()
     return propNodeGhost(_cmdArg);
 }
 
+void FGNasalSys::setCmdArg(SGPropertyNode* aNode)
+{
+    _cmdArg = aNode;
+}
+
 void FGNasalSys::init()
 {
+    if (_inited) {
+        SG_LOG(SG_GENERAL, SG_ALERT, "duplicate init of Nasal");
+    }
     int i;
 
     _context = naNewContext();
@@ -841,11 +815,26 @@ void FGNasalSys::init()
     // And our SGPropertyNode wrapper
     hashset(_globals, "props", genPropsModule());
 
-    // Make a "__gcsave" hash to hold the naRef objects which get
-    // passed to handles outside the interpreter (to protect them from
-    // begin garbage-collected).
-    _gcHash = naNewHash(_context);
-    hashset(_globals, "__gcsave", _gcHash);
+    // Add string methods
+    _string = naInit_string(_context);
+    naSave(_context, _string);
+    initNasalString(_globals, _string, _context);
+
+    initNasalPositioned(_globals, _context);
+    initNasalPositioned_cppbind(_globals, _context);
+    initNasalAircraft(_globals, _context);
+    NasalClipboard::init(this);
+    initNasalCanvas(_globals, _context);
+    initNasalCondition(_globals, _context);
+    initNasalHTTP(_globals, _context);
+    initNasalSGPath(_globals, _context);
+  
+    NasalTimerObj::init("Timer")
+      .method("start", &TimerObj::start)
+      .method("stop", &TimerObj::stop)
+      .method("restart", &TimerObj::restart)
+      .member("singleShot", &TimerObj::isSingleShot, &TimerObj::setSingleShot)
+      .member("isRunning", &TimerObj::isRunning);
 
     // Now load the various source files in the Nasal directory
     simgear::Dir nasalDir(SGPath(globals->get_fg_root(), "Nasal"));
@@ -864,20 +853,102 @@ void FGNasalSys::init()
     const char *s = "nasal-dir-initialized";
     SGPropertyNode *signal = fgGetNode("/sim/signals", true);
     signal->setBoolValue(s, true);
-    signal->removeChildren(s, false);
+    signal->removeChildren(s);
 
     // Pull scripts out of the property tree, too
     loadPropertyScripts();
+  
+    // now Nasal modules are loaded, we can do some delayed work
+    postinitNasalPositioned(_globals, _context);
+    postinitNasalGUI(_globals, _context);
+    
+    _inited = true;
+}
+
+void FGNasalSys::shutdown()
+{
+    if (!_inited) {
+        return;
+    }
+    
+    shutdownNasalPositioned();
+    
+    map<int, FGNasalListener *>::iterator it, end = _listener.end();
+    for(it = _listener.begin(); it != end; ++it)
+        delete it->second;
+    _listener.clear();
+    
+    NasalCommandDict::iterator j = _commands.begin();
+    for (; j != _commands.end(); ++j) {
+        globals->get_commands()->removeCommand(j->first);
+    }
+    _commands.clear();
+    
+    std::vector<FGNasalModuleListener*>::iterator k = _moduleListeners.begin();
+    for(; k!= _moduleListeners.end(); ++k)
+        delete *k;
+    _moduleListeners.clear();
+    
+    naClearSaved();
+    
+    _string = naNil(); // will be freed by _context
+    naFreeContext(_context);
+   
+    //setWatchedRef(_globals);
+    
+    // remove the recursive reference in globals
+    hashset(_globals, "globals", naNil());
+    _globals = naNil();    
+    
+    naGC();
+    _inited = false;
+}
+
+naRef FGNasalSys::wrappedPropsNode(SGPropertyNode* aProps)
+{
+    if (naIsNil(_wrappedNodeFunc)) {
+        nasal::Hash props = getGlobals().get<nasal::Hash>("props");
+        _wrappedNodeFunc = props.get("wrapNode");
+    }
+    
+    naRef args[1];
+    args[0] = propNodeGhost(aProps);
+    naContext ctx = naNewContext();
+    naRef wrapped = naCall(ctx, _wrappedNodeFunc, 1, args, naNil(), naNil());
+    naFreeContext(ctx);
+    return wrapped;
 }
 
 void FGNasalSys::update(double)
 {
+    if( NasalClipboard::getInstance() )
+        NasalClipboard::getInstance()->update();
+
     if(!_dead_listener.empty()) {
         vector<FGNasalListener *>::iterator it, end = _dead_listener.end();
         for(it = _dead_listener.begin(); it != end; ++it) delete *it;
         _dead_listener.clear();
     }
 
+    if (!_loadList.empty())
+    {
+        if( _delay_load )
+          _delay_load = false;
+        else
+          // process Nasal load hook (only one per update loop to avoid excessive lags)
+          _loadList.pop()->load();
+    }
+    else
+    if (!_unloadList.empty())
+    {
+        // process pending Nasal unload hooks after _all_ load hooks were processed
+        // (only unload one per update loop to avoid excessive lags)
+        _unloadList.pop()->unload();
+    }
+
+    // Destroy all queued ghosts
+    nasal::ghostProcessDestroyList();
+
     // The global context is a legacy thing.  We use dynamically
     // created contexts for naCall() now, so that we can call them
     // recursively.  But there are still spots that want to use it for
@@ -901,10 +972,8 @@ bool pathSortPredicate(const SGPath& p1, const SGPath& p2)
 void FGNasalSys::loadScriptDirectory(simgear::Dir nasalDir)
 {
     simgear::PathList scripts = nasalDir.children(simgear::Dir::TYPE_FILE, ".nas");
-    // sort scripts, avoid loading sequence effects due to file system's
-    // random directory order
-    std::sort(scripts.begin(), scripts.end(), pathSortPredicate);
-
+    // Note: simgear::Dir already reports file entries in a deterministic order,
+    // so a fixed loading sequence is guaranteed (same for every user)
     for (unsigned int i=0; i<scripts.size(); ++i) {
       SGPath fullpath(scripts[i]);
       SGPath file = fullpath.file();
@@ -915,7 +984,7 @@ void FGNasalSys::loadScriptDirectory(simgear::Dir nasalDir)
 // Create module with list of scripts
 void FGNasalSys::addModule(string moduleName, simgear::PathList scripts)
 {
-    if (scripts.size()>0)
+    if (! scripts.empty())
     {
         SGPropertyNode* nasal = globals->get_props()->getNode("nasal");
         SGPropertyNode* module_node = nasal->getChild(moduleName,0,true);
@@ -1004,6 +1073,7 @@ void FGNasalSys::loadPropertyScripts(SGPropertyNode* n)
         if (enable)
         {
             FGNasalModuleListener* listener = new FGNasalModuleListener(n);
+            _moduleListeners.push_back(listener);
             enable->addChangeListener(listener, false);
         }
     }
@@ -1015,12 +1085,14 @@ void FGNasalSys::loadPropertyScripts(SGPropertyNode* n)
 // Logs a runtime error, with stack trace, to the FlightGear log stream
 void FGNasalSys::logError(naContext context)
 {
-    SG_LOG(SG_NASAL, SG_ALERT,
-           "Nasal runtime error: " << naGetError(context));
+    SG_LOG(SG_NASAL, SG_ALERT, "Nasal runtime error: " << naGetError(context));
+    int stack_depth = naStackDepth(context);
+    if( stack_depth < 1 )
+      return;
     SG_LOG(SG_NASAL, SG_ALERT,
            "  at " << naStr_data(naGetSourceFile(context, 0)) <<
            ", line " << naGetLine(context, 0));
-    for(int i=1; i<naStackDepth(context); i++)
+    for(int i=1; i<stack_depth; i++)
         SG_LOG(SG_NASAL, SG_ALERT,
                "  called from: " << naStr_data(naGetSourceFile(context, i)) <<
                ", line " << naGetLine(context, i));
@@ -1054,66 +1126,85 @@ bool FGNasalSys::createModule(const char* moduleName, const char* fileName,
                               const SGPropertyNode* cmdarg,
                               int argc, naRef* args)
 {
-    naRef code = parse(fileName, src, len);
-    if(naIsNil(code))
+    naContext ctx = naNewContext();
+    naRef code = parse(ctx, fileName, src, len);
+    if(naIsNil(code)) {
+        naFreeContext(ctx);
         return false;
+    }
 
+    
     // See if we already have a module hash to use.  This allows the
     // user to, for example, add functions to the built-in math
     // module.  Make a new one if necessary.
     naRef locals;
-    naRef modname = naNewString(_context);
+    naRef modname = naNewString(ctx);
     naStr_fromdata(modname, (char*)moduleName, strlen(moduleName));
     if(!naHash_get(_globals, modname, &locals))
-        locals = naNewHash(_context);
+        locals = naNewHash(ctx);
 
     _cmdArg = (SGPropertyNode*)cmdarg;
 
-    call(code, argc, args, locals);
+    callWithContext(ctx, code, argc, args, locals);
     hashset(_globals, moduleName, locals);
+    
+    naFreeContext(ctx);
     return true;
 }
 
 void FGNasalSys::deleteModule(const char* moduleName)
 {
-    naRef modname = naNewString(_context);
+    if (!_inited) {
+        // can occur on shutdown due to us being shutdown first, but other
+        // subsystems having Nasal objects.
+        return;
+    }
+    
+    naContext ctx = naNewContext();
+    naRef modname = naNewString(ctx);
     naStr_fromdata(modname, (char*)moduleName, strlen(moduleName));
     naHash_delete(_globals, modname);
+    naFreeContext(ctx);
 }
 
-naRef FGNasalSys::parse(const char* filename, const char* buf, int len)
+naRef FGNasalSys::parse(naContext ctx, const char* filename, const char* buf, int len)
 {
     int errLine = -1;
-    naRef srcfile = naNewString(_context);
+    naRef srcfile = naNewString(ctx);
     naStr_fromdata(srcfile, (char*)filename, strlen(filename));
-    naRef code = naParseCode(_context, srcfile, 1, (char*)buf, len, &errLine);
+    naRef code = naParseCode(ctx, srcfile, 1, (char*)buf, len, &errLine);
     if(naIsNil(code)) {
         SG_LOG(SG_NASAL, SG_ALERT,
-               "Nasal parse error: " << naGetError(_context) <<
+               "Nasal parse error: " << naGetError(ctx) <<
                " in "<< filename <<", line " << errLine);
         return naNil();
     }
 
     // Bind to the global namespace before returning
-    return naBindFunction(_context, code, _globals);
+    return naBindFunction(ctx, code, _globals);
 }
 
-bool FGNasalSys::handleCommand(const SGPropertyNode* arg)
+bool FGNasalSys::handleCommand( const char* moduleName,
+                                const char* fileName,
+                                const char* src,
+                                const SGPropertyNode* arg )
 {
-    const char* nasal = arg->getStringValue("script");
-    const char* moduleName = arg->getStringValue("module");
-    naRef code = parse(arg->getPath(true).c_str(), nasal, strlen(nasal));
-    if(naIsNil(code)) return false;
+    naContext ctx = naNewContext();
+    naRef code = parse(ctx, fileName, src, strlen(src));
+    if(naIsNil(code)) {
+        naFreeContext(ctx);
+        return false;
+    }
 
     // Commands can be run "in" a module.  Make sure that module
     // exists, and set it up as the local variables hash for the
     // command.
     naRef locals = naNil();
     if(moduleName[0]) {
-        naRef modname = naNewString(_context);
+        naRef modname = naNewString(ctx);
         naStr_fromdata(modname, (char*)moduleName, strlen(moduleName));
         if(!naHash_get(_globals, modname, &locals)) {
-            locals = naNewHash(_context);
+            locals = naNewHash(ctx);
             naHash_set(_globals, modname, locals);
         }
     }
@@ -1123,10 +1214,22 @@ bool FGNasalSys::handleCommand(const SGPropertyNode* arg)
     // code doesn't need it.
     _cmdArg = (SGPropertyNode*)arg;
 
-    call(code, 0, 0, locals);
+    callWithContext(ctx, code, 0, 0, locals);
+    naFreeContext(ctx);
     return true;
 }
 
+bool FGNasalSys::handleCommand(const SGPropertyNode* arg)
+{
+  const char* src = arg->getStringValue("script");
+  const char* moduleName = arg->getStringValue("module");
+
+  return handleCommand( moduleName,
+                        arg->getPath(true).c_str(),
+                        src,
+                        arg );
+}
+
 // settimer(func, dt, simtime) extension function.  The first argument
 // is a Nasal function to call, the second is a delta time (from now),
 // in seconds.  The third, if present, is a boolean value indicating
@@ -1173,14 +1276,12 @@ void FGNasalSys::handleTimer(NasalTimer* t)
 
 int FGNasalSys::gcSave(naRef r)
 {
-    int key = _nextGCKey++;
-    naHash_set(_gcHash, naNum(key), r);
-    return key;
+    return naGCSave(r);
 }
 
 void FGNasalSys::gcRelease(int key)
 {
-    naHash_delete(_gcHash, naNum(key));
+    naGCRelease(key);
 }
 
 void FGNasalSys::NasalTimer::timerExpired()
@@ -1251,8 +1352,43 @@ naRef FGNasalSys::removeListener(naContext c, int argc, naRef* args)
     return naNum(_listener.size());
 }
 
+void FGNasalSys::registerToLoad(FGNasalModelData *data)
+{
+  if( _loadList.empty() )
+    _delay_load = true;
+  _loadList.push(data);
+}
 
+void FGNasalSys::registerToUnload(FGNasalModelData *data)
+{
+    _unloadList.push(data);
+}
 
+void FGNasalSys::addCommand(naRef func, const std::string& name)
+{
+    if (_commands.find(name) != _commands.end()) {
+        SG_LOG(SG_NASAL, SG_WARN, "duplicate add of command:" << name);
+        return;
+    }
+    
+    NasalCommand* cmd = new NasalCommand(this, func, name);
+    _commands[name] = cmd;
+}
+
+void FGNasalSys::removeCommand(const std::string& name)
+{
+    NasalCommandDict::iterator it = _commands.find(name);
+    if (it == _commands.end()) {
+        SG_LOG(SG_NASAL, SG_WARN, "remove of unknwon command:" << name);
+        return;
+    }
+
+    // will delete the NasalCommand instance
+    globals->get_commands()->removeCommand(name);
+    _commands.erase(it);
+}
+
+//////////////////////////////////////////////////////////////////////////
 // FGNasalListener class.
 
 FGNasalListener::FGNasalListener(SGPropertyNode *node, naRef code,
@@ -1283,7 +1419,6 @@ FGNasalListener::~FGNasalListener()
 void FGNasalListener::call(SGPropertyNode* which, naRef mode)
 {
     if(_active || _dead) return;
-    SG_LOG(SG_NASAL, SG_DEBUG, "trigger listener #" << _id);
     _active++;
     naRef arg[4];
     arg[0] = _nas->propNodeGhost(which);
@@ -1349,62 +1484,6 @@ bool FGNasalListener::changed(SGPropertyNode* node)
     }
 }
 
-
-
-// FGNasalModelData class.  If sgLoad3DModel() is called with a pointer to
-// such a class, then it lets modelLoaded() run the <load> script, and the
-// destructor the <unload> script. The latter happens when the model branch
-// is removed from the scene graph.
-
-unsigned int FGNasalModelData::_module_id = 0;
-
-void FGNasalModelData::modelLoaded(const string& path, SGPropertyNode *prop,
-                                   osg::Node *)
-{
-    if(!prop)
-        return;
-    SGPropertyNode *nasal = prop->getNode("nasal");
-    if(!nasal)
-        return;
-
-    SGPropertyNode *load = nasal->getNode("load");
-    _unload = nasal->getNode("unload");
-    if(!load && !_unload)
-        return;
-
-    std::stringstream m;
-    m << "__model" << _module_id++;
-    _module = m.str();
-
-    const char *s = load ? load->getStringValue() : "";
-
-    naRef arg[2];
-    arg[0] = nasalSys->propNodeGhost(_root);
-    arg[1] = nasalSys->propNodeGhost(prop);
-    nasalSys->createModule(_module.c_str(), path.c_str(), s, strlen(s),
-                           _root, 2, arg);
-}
-
-FGNasalModelData::~FGNasalModelData()
-{
-    if(_module.empty())
-        return;
-
-    if(!nasalSys) {
-        SG_LOG(SG_NASAL, SG_WARN, "Trying to run an <unload> script "
-                "without Nasal subsystem present.");
-        return;
-    }
-
-    if(_unload) {
-        const char *s = _unload->getStringValue();
-        nasalSys->createModule(_module.c_str(), _module.c_str(), s, strlen(s), _root);
-    }
-    nasalSys->deleteModule(_module.c_str());
-}
-
-
-
 // NasalXMLVisitor class: handles EasyXML visitor callback for parsexml()
 //
 NasalXMLVisitor::NasalXMLVisitor(naContext c, int argc, naRef* args) :