diff --git a/panda/src/egg/eggData.cxx b/panda/src/egg/eggData.cxx
index 22b4615f48..4965454be0 100644
--- a/panda/src/egg/eggData.cxx
+++ b/panda/src/egg/eggData.cxx
@@ -28,6 +28,7 @@
 #include "string_utils.h"
 #include "dSearchPath.h"
 #include "virtualFileSystem.h"
+#include "mutexHolder.h"
 #include "zStream.h"
 
 extern int eggyyparse();
@@ -122,16 +123,22 @@ read(istream &in) {
   // it with a copy of ourselves, so that it will get our _coordsys
   // value, if the user set it.
   PT(EggData) data = new EggData(*this);
-  egg_init_parser(in, get_egg_filename(), data, data);
-  eggyyparse();
-  egg_cleanup_parser();
+
+  int error_count;
+  {
+    MutexHolder holder(egg_lock);
+    egg_init_parser(in, get_egg_filename(), data, data);
+    eggyyparse();
+    egg_cleanup_parser();
+    error_count = egg_error_count();
+  }
 
   data->post_read();
 
   steal_children(*data);
   (*this) = *data;
 
-  return (egg_error_count() == 0);
+  return (error_count == 0);
 }
 
 ////////////////////////////////////////////////////////////////////
diff --git a/panda/src/egg/eggNode.cxx b/panda/src/egg/eggNode.cxx
index 1e29ae24c5..c3daec372e 100644
--- a/panda/src/egg/eggNode.cxx
+++ b/panda/src/egg/eggNode.cxx
@@ -257,6 +257,9 @@ parse_egg(const string &egg_syntax) {
   }
 
   istringstream in(egg_syntax);
+
+  MutexHolder holder(egg_lock);
+
   egg_init_parser(in, "", this, group);
 
   if (!egg_start_parse_body()) {
diff --git a/panda/src/egg/lexer.cxx.prebuilt b/panda/src/egg/lexer.cxx.prebuilt
index f580e8bbd5..c9db6986f0 100644
--- a/panda/src/egg/lexer.cxx.prebuilt
+++ b/panda/src/egg/lexer.cxx.prebuilt
@@ -727,16 +727,16 @@ char *yytext;
 ////////////////////////////////////////////////////////////////////
 */
 #line 9 "lexer.lxx"
+#include "pandabase.h"
 #include "lexerDefs.h"
 #include "parserDefs.h"
 #include "config_egg.h"
 #include "parser.h"
-
 #include "indent.h"
 #include "pnotify.h"
+#include "pmutex.h"
 
 #include <math.h>
-#include "pandabase.h"
 
 extern "C" int eggyywrap(void);  // declared below.
 
@@ -747,6 +747,9 @@ static int yyinput(void);        // declared by flex.
 // Static variables
 ////////////////////////////////////////////////////////////////////
 
+// This mutex protects all of these global variables. 
+Mutex egg_lock; 
+
 // We'll increment line_number and col_number as we parse the file, so
 // that we can report the position of an error.
 static int line_number = 0;
@@ -771,7 +774,6 @@ static string egg_filename;
 // the yacc grammar to start from initial points.
 static int initial_token;
 
-
 ////////////////////////////////////////////////////////////////////
 // Defining the interface to the lexer.
 ////////////////////////////////////////////////////////////////////
@@ -1002,7 +1004,7 @@ INLINE void accept() {
   col_number += yyleng;
 }
 
-#line 1007 "lex.yy.c"
+#line 1009 "lex.yy.c"
 
 /* Macros after this point can all be overridden by user definitions in
  * section 1.
@@ -1164,7 +1166,7 @@ YY_DECL
 	register char *yy_cp, *yy_bp;
 	register int yy_act;
 
-#line 290 "lexer.lxx"
+#line 292 "lexer.lxx"
 
 
 
@@ -1175,7 +1177,7 @@ YY_DECL
   }
 
 
-#line 1180 "lex.yy.c"
+#line 1182 "lex.yy.c"
 
 	if ( yy_init )
 		{
@@ -1260,7 +1262,7 @@ do_action:	/* This label is used only to access EOF actions. */
 
 case 1:
 YY_RULE_SETUP
-#line 300 "lexer.lxx"
+#line 302 "lexer.lxx"
 {
   // New line.  Save a copy of the line so we can print it out for the
   // benefit of the user in case we get an error.
@@ -1277,7 +1279,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 2:
 YY_RULE_SETUP
-#line 314 "lexer.lxx"
+#line 316 "lexer.lxx"
 { 
   // Eat whitespace.
   accept();
@@ -1285,7 +1287,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 3:
 YY_RULE_SETUP
-#line 319 "lexer.lxx"
+#line 321 "lexer.lxx"
 { 
   // Eat C++-style comments.
   accept();
@@ -1293,7 +1295,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 4:
 YY_RULE_SETUP
-#line 324 "lexer.lxx"
+#line 326 "lexer.lxx"
 {
   // Eat C-style comments.
   accept();
@@ -1302,7 +1304,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 5:
 YY_RULE_SETUP
-#line 330 "lexer.lxx"
+#line 332 "lexer.lxx"
 {
   // Send curly braces as themselves.
   accept(); 
@@ -1311,7 +1313,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 6:
 YY_RULE_SETUP
-#line 338 "lexer.lxx"
+#line 340 "lexer.lxx"
 {
   accept();
   return BEZIERCURVE;
@@ -1319,7 +1321,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 7:
 YY_RULE_SETUP
-#line 342 "lexer.lxx"
+#line 344 "lexer.lxx"
 {
   accept();
   return BFACE;
@@ -1327,7 +1329,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 8:
 YY_RULE_SETUP
-#line 346 "lexer.lxx"
+#line 348 "lexer.lxx"
 {
   accept();
   return BILLBOARD;
@@ -1335,7 +1337,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 9:
 YY_RULE_SETUP
-#line 350 "lexer.lxx"
+#line 352 "lexer.lxx"
 {
   accept();
   return BILLBOARDCENTER;
@@ -1343,7 +1345,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 10:
 YY_RULE_SETUP
-#line 354 "lexer.lxx"
+#line 356 "lexer.lxx"
 {
   accept();
   return BINORMAL;
@@ -1351,7 +1353,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 11:
 YY_RULE_SETUP
-#line 358 "lexer.lxx"
+#line 360 "lexer.lxx"
 {
   accept();
   return BUNDLE;
@@ -1359,7 +1361,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 12:
 YY_RULE_SETUP
-#line 362 "lexer.lxx"
+#line 364 "lexer.lxx"
 {
   accept();
   return SCALAR;
@@ -1367,7 +1369,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 13:
 YY_RULE_SETUP
-#line 366 "lexer.lxx"
+#line 368 "lexer.lxx"
 {
   accept();
   return CLOSED;
@@ -1375,7 +1377,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 14:
 YY_RULE_SETUP
-#line 370 "lexer.lxx"
+#line 372 "lexer.lxx"
 {
   accept();
   return COLLIDE;
@@ -1383,7 +1385,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 15:
 YY_RULE_SETUP
-#line 374 "lexer.lxx"
+#line 376 "lexer.lxx"
 {
   accept();
   return COMMENT;
@@ -1391,7 +1393,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 16:
 YY_RULE_SETUP
-#line 378 "lexer.lxx"
+#line 380 "lexer.lxx"
 {
   accept();
   return COMPONENT;
@@ -1399,7 +1401,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 17:
 YY_RULE_SETUP
-#line 382 "lexer.lxx"
+#line 384 "lexer.lxx"
 {
   accept();
   return COORDSYSTEM;
@@ -1407,7 +1409,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 18:
 YY_RULE_SETUP
-#line 386 "lexer.lxx"
+#line 388 "lexer.lxx"
 {
   accept();
   return CV;
@@ -1415,7 +1417,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 19:
 YY_RULE_SETUP
-#line 390 "lexer.lxx"
+#line 392 "lexer.lxx"
 {
   accept();
   return DART;
@@ -1423,7 +1425,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 20:
 YY_RULE_SETUP
-#line 394 "lexer.lxx"
+#line 396 "lexer.lxx"
 {
   accept();
   return DNORMAL;
@@ -1431,7 +1433,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 21:
 YY_RULE_SETUP
-#line 398 "lexer.lxx"
+#line 400 "lexer.lxx"
 {
   accept();
   return DRGBA;
@@ -1439,7 +1441,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 22:
 YY_RULE_SETUP
-#line 402 "lexer.lxx"
+#line 404 "lexer.lxx"
 {
   accept();
   return DUV;
@@ -1447,7 +1449,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 23:
 YY_RULE_SETUP
-#line 406 "lexer.lxx"
+#line 408 "lexer.lxx"
 {
   accept();
   return DXYZ;
@@ -1455,7 +1457,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 24:
 YY_RULE_SETUP
-#line 410 "lexer.lxx"
+#line 412 "lexer.lxx"
 {
   accept();
   return DCS;
@@ -1463,7 +1465,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 25:
 YY_RULE_SETUP
-#line 414 "lexer.lxx"
+#line 416 "lexer.lxx"
 {
   accept();
   return DISTANCE;
@@ -1471,7 +1473,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 26:
 YY_RULE_SETUP
-#line 418 "lexer.lxx"
+#line 420 "lexer.lxx"
 {
   accept();
   return DTREF;
@@ -1479,7 +1481,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 27:
 YY_RULE_SETUP
-#line 422 "lexer.lxx"
+#line 424 "lexer.lxx"
 {
   accept();
   return DYNAMICVERTEXPOOL;
@@ -1487,7 +1489,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 28:
 YY_RULE_SETUP
-#line 426 "lexer.lxx"
+#line 428 "lexer.lxx"
 {
   accept();
   return EXTERNAL_FILE;
@@ -1495,7 +1497,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 29:
 YY_RULE_SETUP
-#line 430 "lexer.lxx"
+#line 432 "lexer.lxx"
 {
   accept();
   return FLIGHT;
@@ -1503,7 +1505,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 30:
 YY_RULE_SETUP
-#line 434 "lexer.lxx"
+#line 436 "lexer.lxx"
 {
   accept();
   return GROUP;
@@ -1511,7 +1513,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 31:
 YY_RULE_SETUP
-#line 438 "lexer.lxx"
+#line 440 "lexer.lxx"
 {
   accept();
   return HIP;
@@ -1519,7 +1521,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 32:
 YY_RULE_SETUP
-#line 442 "lexer.lxx"
+#line 444 "lexer.lxx"
 {
   accept();
   return INTANGENT;
@@ -1527,7 +1529,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 33:
 YY_RULE_SETUP
-#line 446 "lexer.lxx"
+#line 448 "lexer.lxx"
 {
   accept();
   return JOINT;
@@ -1535,7 +1537,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 34:
 YY_RULE_SETUP
-#line 450 "lexer.lxx"
+#line 452 "lexer.lxx"
 {
   accept();
   return KNOTS;
@@ -1543,7 +1545,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 35:
 YY_RULE_SETUP
-#line 454 "lexer.lxx"
+#line 456 "lexer.lxx"
 {
   accept();
   return INCLUDE;
@@ -1551,7 +1553,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 36:
 YY_RULE_SETUP
-#line 458 "lexer.lxx"
+#line 460 "lexer.lxx"
 {
   accept();
   return INSTANCE;
@@ -1559,7 +1561,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 37:
 YY_RULE_SETUP
-#line 462 "lexer.lxx"
+#line 464 "lexer.lxx"
 {
   accept();
   return LINE;
@@ -1567,7 +1569,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 38:
 YY_RULE_SETUP
-#line 466 "lexer.lxx"
+#line 468 "lexer.lxx"
 {
   accept();
   return LOOP;
@@ -1575,7 +1577,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 39:
 YY_RULE_SETUP
-#line 470 "lexer.lxx"
+#line 472 "lexer.lxx"
 {
   accept();
   return MATERIAL;
@@ -1583,7 +1585,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 40:
 YY_RULE_SETUP
-#line 474 "lexer.lxx"
+#line 476 "lexer.lxx"
 {
   accept();
   return MATRIX3;
@@ -1591,7 +1593,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 41:
 YY_RULE_SETUP
-#line 478 "lexer.lxx"
+#line 480 "lexer.lxx"
 {
   accept();
   return MATRIX4;
@@ -1599,7 +1601,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 42:
 YY_RULE_SETUP
-#line 482 "lexer.lxx"
+#line 484 "lexer.lxx"
 {
   accept();
   return MODEL;
@@ -1607,7 +1609,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 43:
 YY_RULE_SETUP
-#line 486 "lexer.lxx"
+#line 488 "lexer.lxx"
 {
   accept();
   return MREF;
@@ -1615,7 +1617,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 44:
 YY_RULE_SETUP
-#line 490 "lexer.lxx"
+#line 492 "lexer.lxx"
 {
   accept();
   return NORMAL;
@@ -1623,7 +1625,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 45:
 YY_RULE_SETUP
-#line 494 "lexer.lxx"
+#line 496 "lexer.lxx"
 {
   accept();
   return NURBSCURVE;
@@ -1631,7 +1633,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 46:
 YY_RULE_SETUP
-#line 498 "lexer.lxx"
+#line 500 "lexer.lxx"
 {
   accept();
   return NURBSSURFACE;
@@ -1639,7 +1641,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 47:
 YY_RULE_SETUP
-#line 502 "lexer.lxx"
+#line 504 "lexer.lxx"
 {
   accept();
   return OBJECTTYPE;
@@ -1647,7 +1649,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 48:
 YY_RULE_SETUP
-#line 506 "lexer.lxx"
+#line 508 "lexer.lxx"
 {
   accept();
   return ORDER;
@@ -1655,7 +1657,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 49:
 YY_RULE_SETUP
-#line 510 "lexer.lxx"
+#line 512 "lexer.lxx"
 {
   accept();
   return OUTTANGENT;
@@ -1663,7 +1665,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 50:
 YY_RULE_SETUP
-#line 514 "lexer.lxx"
+#line 516 "lexer.lxx"
 {
   accept();
   return POINTLIGHT;
@@ -1671,7 +1673,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 51:
 YY_RULE_SETUP
-#line 518 "lexer.lxx"
+#line 520 "lexer.lxx"
 {
   accept();
   return POLYGON;
@@ -1679,7 +1681,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 52:
 YY_RULE_SETUP
-#line 522 "lexer.lxx"
+#line 524 "lexer.lxx"
 {
   accept();
   return REF;
@@ -1687,7 +1689,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 53:
 YY_RULE_SETUP
-#line 526 "lexer.lxx"
+#line 528 "lexer.lxx"
 {
   accept();
   return RGBA;
@@ -1695,7 +1697,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 54:
 YY_RULE_SETUP
-#line 530 "lexer.lxx"
+#line 532 "lexer.lxx"
 {
   accept();
   return ROTATE;
@@ -1703,7 +1705,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 55:
 YY_RULE_SETUP
-#line 534 "lexer.lxx"
+#line 536 "lexer.lxx"
 {
   accept();
   return ROTX;
@@ -1711,7 +1713,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 56:
 YY_RULE_SETUP
-#line 538 "lexer.lxx"
+#line 540 "lexer.lxx"
 {
   accept();
   return ROTY;
@@ -1719,7 +1721,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 57:
 YY_RULE_SETUP
-#line 542 "lexer.lxx"
+#line 544 "lexer.lxx"
 {
   accept();
   return ROTZ;
@@ -1727,7 +1729,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 58:
 YY_RULE_SETUP
-#line 546 "lexer.lxx"
+#line 548 "lexer.lxx"
 {
   accept();
   return SANIM;
@@ -1735,7 +1737,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 59:
 YY_RULE_SETUP
-#line 550 "lexer.lxx"
+#line 552 "lexer.lxx"
 {
   accept();
   return SCALAR;
@@ -1743,7 +1745,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 60:
 YY_RULE_SETUP
-#line 554 "lexer.lxx"
+#line 556 "lexer.lxx"
 {
   accept();
   return SCALE;
@@ -1751,7 +1753,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 61:
 YY_RULE_SETUP
-#line 558 "lexer.lxx"
+#line 560 "lexer.lxx"
 {
   accept();
   return SEQUENCE;
@@ -1759,7 +1761,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 62:
 YY_RULE_SETUP
-#line 562 "lexer.lxx"
+#line 564 "lexer.lxx"
 {
   accept();
   return SHADING;
@@ -1767,7 +1769,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 63:
 YY_RULE_SETUP
-#line 566 "lexer.lxx"
+#line 568 "lexer.lxx"
 {
   accept();
   return SWITCH;
@@ -1775,7 +1777,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 64:
 YY_RULE_SETUP
-#line 570 "lexer.lxx"
+#line 572 "lexer.lxx"
 {
   accept();
   return SWITCHCONDITION;
@@ -1783,7 +1785,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 65:
 YY_RULE_SETUP
-#line 574 "lexer.lxx"
+#line 576 "lexer.lxx"
 {
   accept();
   return TABLE;
@@ -1791,7 +1793,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 66:
 YY_RULE_SETUP
-#line 578 "lexer.lxx"
+#line 580 "lexer.lxx"
 {
   accept();
   return TABLE_V;
@@ -1799,7 +1801,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 67:
 YY_RULE_SETUP
-#line 582 "lexer.lxx"
+#line 584 "lexer.lxx"
 {
   accept();
   return TAG;
@@ -1807,7 +1809,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 68:
 YY_RULE_SETUP
-#line 586 "lexer.lxx"
+#line 588 "lexer.lxx"
 {
   accept();
   return TANGENT;
@@ -1815,7 +1817,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 69:
 YY_RULE_SETUP
-#line 590 "lexer.lxx"
+#line 592 "lexer.lxx"
 {
   accept();
   return TEXLIST;
@@ -1823,7 +1825,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 70:
 YY_RULE_SETUP
-#line 594 "lexer.lxx"
+#line 596 "lexer.lxx"
 {
   accept();
   return TEXTURE;
@@ -1831,7 +1833,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 71:
 YY_RULE_SETUP
-#line 598 "lexer.lxx"
+#line 600 "lexer.lxx"
 {
   accept();
   return TLENGTHS;
@@ -1839,7 +1841,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 72:
 YY_RULE_SETUP
-#line 602 "lexer.lxx"
+#line 604 "lexer.lxx"
 {
   accept();
   return TRANSFORM;
@@ -1847,7 +1849,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 73:
 YY_RULE_SETUP
-#line 606 "lexer.lxx"
+#line 608 "lexer.lxx"
 {
   accept();
   return TRANSLATE;
@@ -1855,7 +1857,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 74:
 YY_RULE_SETUP
-#line 610 "lexer.lxx"
+#line 612 "lexer.lxx"
 {
   accept();
   return TREF;
@@ -1863,7 +1865,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 75:
 YY_RULE_SETUP
-#line 614 "lexer.lxx"
+#line 616 "lexer.lxx"
 {
   accept();
   return TRIANGLEFAN;
@@ -1871,7 +1873,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 76:
 YY_RULE_SETUP
-#line 618 "lexer.lxx"
+#line 620 "lexer.lxx"
 {
   accept();
   return TRIANGLESTRIP;
@@ -1879,7 +1881,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 77:
 YY_RULE_SETUP
-#line 622 "lexer.lxx"
+#line 624 "lexer.lxx"
 {
   accept();
   return TRIM;
@@ -1887,7 +1889,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 78:
 YY_RULE_SETUP
-#line 626 "lexer.lxx"
+#line 628 "lexer.lxx"
 {
   accept();
   return TXT;
@@ -1895,7 +1897,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 79:
 YY_RULE_SETUP
-#line 630 "lexer.lxx"
+#line 632 "lexer.lxx"
 {
   accept();
   return UKNOTS;
@@ -1903,7 +1905,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 80:
 YY_RULE_SETUP
-#line 634 "lexer.lxx"
+#line 636 "lexer.lxx"
 {
   accept();
   return UKNOTS;
@@ -1911,7 +1913,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 81:
 YY_RULE_SETUP
-#line 638 "lexer.lxx"
+#line 640 "lexer.lxx"
 {
   accept();
   return UV;
@@ -1919,7 +1921,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 82:
 YY_RULE_SETUP
-#line 642 "lexer.lxx"
+#line 644 "lexer.lxx"
 {
   accept();
   return VKNOTS;
@@ -1927,7 +1929,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 83:
 YY_RULE_SETUP
-#line 646 "lexer.lxx"
+#line 648 "lexer.lxx"
 {
   accept();
   return VKNOTS;
@@ -1935,7 +1937,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 84:
 YY_RULE_SETUP
-#line 650 "lexer.lxx"
+#line 652 "lexer.lxx"
 {
   accept();
   return VERTEX;
@@ -1943,7 +1945,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 85:
 YY_RULE_SETUP
-#line 654 "lexer.lxx"
+#line 656 "lexer.lxx"
 {
   accept();
   return VERTEXANIM;
@@ -1951,7 +1953,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 86:
 YY_RULE_SETUP
-#line 658 "lexer.lxx"
+#line 660 "lexer.lxx"
 {
   accept();
   return VERTEXPOOL;
@@ -1959,7 +1961,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 87:
 YY_RULE_SETUP
-#line 662 "lexer.lxx"
+#line 664 "lexer.lxx"
 {
   accept();
   return VERTEXREF;
@@ -1967,7 +1969,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 88:
 YY_RULE_SETUP
-#line 666 "lexer.lxx"
+#line 668 "lexer.lxx"
 {
   accept();
   return XFMANIM;
@@ -1975,7 +1977,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 89:
 YY_RULE_SETUP
-#line 670 "lexer.lxx"
+#line 672 "lexer.lxx"
 {
   accept();
   return XFMSANIM;
@@ -1983,7 +1985,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 90:
 YY_RULE_SETUP
-#line 677 "lexer.lxx"
+#line 679 "lexer.lxx"
 { 
   // An integer or floating-point number.
   accept(); 
@@ -1994,7 +1996,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 91:
 YY_RULE_SETUP
-#line 685 "lexer.lxx"
+#line 687 "lexer.lxx"
 {
   // A hexadecimal integer number.
   accept(); 
@@ -2005,7 +2007,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 92:
 YY_RULE_SETUP
-#line 693 "lexer.lxx"
+#line 695 "lexer.lxx"
 {
   // A binary integer number.
   accept(); 
@@ -2016,7 +2018,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 93:
 YY_RULE_SETUP
-#line 701 "lexer.lxx"
+#line 703 "lexer.lxx"
 {
   // not-a-number.  These sometimes show up in egg files accidentally.
   accept(); 
@@ -2028,7 +2030,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 94:
 YY_RULE_SETUP
-#line 710 "lexer.lxx"
+#line 712 "lexer.lxx"
 { 
   // infinity.  As above.
   accept(); 
@@ -2039,7 +2041,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 95:
 YY_RULE_SETUP
-#line 718 "lexer.lxx"
+#line 720 "lexer.lxx"
 {
   // minus infinity.  As above.
   accept(); 
@@ -2050,7 +2052,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 96:
 YY_RULE_SETUP
-#line 727 "lexer.lxx"
+#line 729 "lexer.lxx"
 {
   // Quoted string.
   accept();
@@ -2060,7 +2062,7 @@ YY_RULE_SETUP
 	YY_BREAK
 case 97:
 YY_RULE_SETUP
-#line 734 "lexer.lxx"
+#line 736 "lexer.lxx"
 { 
   // Unquoted string.
   accept();
@@ -2070,10 +2072,10 @@ YY_RULE_SETUP
 	YY_BREAK
 case 98:
 YY_RULE_SETUP
-#line 740 "lexer.lxx"
+#line 742 "lexer.lxx"
 ECHO;
 	YY_BREAK
-#line 2078 "lex.yy.c"
+#line 2080 "lex.yy.c"
 case YY_STATE_EOF(INITIAL):
 	yyterminate();
 
@@ -2962,4 +2964,4 @@ int main()
 	return 0;
 	}
 #endif
-#line 740 "lexer.lxx"
+#line 742 "lexer.lxx"
diff --git a/panda/src/egg/lexer.lxx b/panda/src/egg/lexer.lxx
index 81070053cc..515ddce0da 100644
--- a/panda/src/egg/lexer.lxx
+++ b/panda/src/egg/lexer.lxx
@@ -6,16 +6,16 @@
 */
 
 %{
+#include "pandabase.h"
 #include "lexerDefs.h"
 #include "parserDefs.h"
 #include "config_egg.h"
 #include "parser.h"
-
 #include "indent.h"
 #include "pnotify.h"
+#include "pmutex.h"
 
 #include <math.h>
-#include "pandabase.h"
 
 extern "C" int eggyywrap(void);  // declared below.
 
@@ -26,6 +26,9 @@ static int yyinput(void);        // declared by flex.
 // Static variables
 ////////////////////////////////////////////////////////////////////
 
+// This mutex protects all of these global variables. 
+Mutex egg_lock; 
+
 // We'll increment line_number and col_number as we parse the file, so
 // that we can report the position of an error.
 static int line_number = 0;
@@ -50,7 +53,6 @@ static string egg_filename;
 // the yacc grammar to start from initial points.
 static int initial_token;
 
-
 ////////////////////////////////////////////////////////////////////
 // Defining the interface to the lexer.
 ////////////////////////////////////////////////////////////////////
diff --git a/panda/src/egg/parser.cxx.prebuilt b/panda/src/egg/parser.cxx.prebuilt
index b55133f753..c82a56f30e 100644
--- a/panda/src/egg/parser.cxx.prebuilt
+++ b/panda/src/egg/parser.cxx.prebuilt
@@ -1,7 +1,7 @@
-/* A Bison parser, made by GNU Bison 2.0.  */
+/* A Bison parser, made by GNU Bison 2.1.  */
 
 /* Skeleton parser for Yacc-like parsing with Bison,
-   Copyright (C) 1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -15,8 +15,8 @@
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
+   Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
 
 /* As a special exception, when this file is copied by Bison into a
    Bison output file, you may use that output file without restriction.
@@ -36,6 +36,9 @@
 /* Identify Bison output.  */
 #define YYBISON 1
 
+/* Bison version.  */
+#define YYBISON_VERSION "2.1"
+
 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
 
@@ -151,6 +154,7 @@
      START_PRIMITIVE_BODY = 345
    };
 #endif
+/* Tokens.  */
 #define EGG_NUMBER 258
 #define EGG_ULONG 259
 #define EGG_STRING 260
@@ -397,6 +401,11 @@ egg_cleanup_parser() {
 # define YYERROR_VERBOSE 0
 #endif
 
+/* Enabling the token table.  */
+#ifndef YYTOKEN_TABLE
+# define YYTOKEN_TABLE 0
+#endif
+
 #if ! defined (YYSTYPE) && ! defined (YYSTYPE_IS_DECLARED)
 typedef int YYSTYPE;
 # define yystype YYSTYPE /* obsolescent; will be withdrawn */
@@ -409,18 +418,37 @@ typedef int YYSTYPE;
 /* Copy the second part of user declarations.  */
 
 
-/* Line 213 of yacc.c.  */
-#line 414 "y.tab.c"
+/* Line 219 of yacc.c.  */
+#line 423 "y.tab.c"
+
+#if ! defined (YYSIZE_T) && defined (__SIZE_TYPE__)
+# define YYSIZE_T __SIZE_TYPE__
+#endif
+#if ! defined (YYSIZE_T) && defined (size_t)
+# define YYSIZE_T size_t
+#endif
+#if ! defined (YYSIZE_T) && (defined (__STDC__) || defined (__cplusplus))
+# include <stddef.h> /* INFRINGES ON USER NAME SPACE */
+# define YYSIZE_T size_t
+#endif
+#if ! defined (YYSIZE_T)
+# define YYSIZE_T unsigned int
+#endif
+
+#ifndef YY_
+# if YYENABLE_NLS
+#  if ENABLE_NLS
+#   include <libintl.h> /* INFRINGES ON USER NAME SPACE */
+#   define YY_(msgid) dgettext ("bison-runtime", msgid)
+#  endif
+# endif
+# ifndef YY_
+#  define YY_(msgid) msgid
+# endif
+#endif
 
 #if ! defined (yyoverflow) || YYERROR_VERBOSE
 
-# ifndef YYFREE
-#  define YYFREE free
-# endif
-# ifndef YYMALLOC
-#  define YYMALLOC malloc
-# endif
-
 /* The parser invokes alloca or malloc; define the necessary symbols.  */
 
 # ifdef YYSTACK_USE_ALLOCA
@@ -429,6 +457,10 @@ typedef int YYSTYPE;
 #    define YYSTACK_ALLOC __builtin_alloca
 #   else
 #    define YYSTACK_ALLOC alloca
+#    if defined (__STDC__) || defined (__cplusplus)
+#     include <stdlib.h> /* INFRINGES ON USER NAME SPACE */
+#     define YYINCLUDED_STDLIB_H
+#    endif
 #   endif
 #  endif
 # endif
@@ -436,13 +468,39 @@ typedef int YYSTYPE;
 # ifdef YYSTACK_ALLOC
    /* Pacify GCC's `empty if-body' warning. */
 #  define YYSTACK_FREE(Ptr) do { /* empty */; } while (0)
-# else
-#  if defined (__STDC__) || defined (__cplusplus)
-#   include <stdlib.h> /* INFRINGES ON USER NAME SPACE */
-#   define YYSIZE_T size_t
+#  ifndef YYSTACK_ALLOC_MAXIMUM
+    /* The OS might guarantee only one guard page at the bottom of the stack,
+       and a page size can be as small as 4096 bytes.  So we cannot safely
+       invoke alloca (N) if N exceeds 4096.  Use a slightly smaller number
+       to allow for a few compiler-allocated temporary stack slots.  */
+#   define YYSTACK_ALLOC_MAXIMUM 4032 /* reasonable circa 2005 */
 #  endif
+# else
 #  define YYSTACK_ALLOC YYMALLOC
 #  define YYSTACK_FREE YYFREE
+#  ifndef YYSTACK_ALLOC_MAXIMUM
+#   define YYSTACK_ALLOC_MAXIMUM ((YYSIZE_T) -1)
+#  endif
+#  ifdef __cplusplus
+extern "C" {
+#  endif
+#  ifndef YYMALLOC
+#   define YYMALLOC malloc
+#   if (! defined (malloc) && ! defined (YYINCLUDED_STDLIB_H) \
+	&& (defined (__STDC__) || defined (__cplusplus)))
+void *malloc (YYSIZE_T); /* INFRINGES ON USER NAME SPACE */
+#   endif
+#  endif
+#  ifndef YYFREE
+#   define YYFREE free
+#   if (! defined (free) && ! defined (YYINCLUDED_STDLIB_H) \
+	&& (defined (__STDC__) || defined (__cplusplus)))
+void free (void *); /* INFRINGES ON USER NAME SPACE */
+#   endif
+#  endif
+#  ifdef __cplusplus
+}
+#  endif
 # endif
 #endif /* ! defined (yyoverflow) || YYERROR_VERBOSE */
 
@@ -477,7 +535,7 @@ union yyalloc
 #   define YYCOPY(To, From, Count)		\
       do					\
 	{					\
-	  register YYSIZE_T yyi;		\
+	  YYSIZE_T yyi;				\
 	  for (yyi = 0; yyi < (Count); yyi++)	\
 	    (To)[yyi] = (From)[yyi];		\
 	}					\
@@ -527,7 +585,7 @@ union yyalloc
 #define YYUNDEFTOK  2
 #define YYMAXUTOK   345
 
-#define YYTRANSLATE(YYX) 						\
+#define YYTRANSLATE(YYX)						\
   ((unsigned int) (YYX) <= YYMAXUTOK ? yytranslate[YYX] : YYUNDEFTOK)
 
 /* YYTRANSLATE[YYLEX] -- Bison symbol number corresponding to YYLEX.  */
@@ -756,8 +814,8 @@ static const unsigned short int yyrline[] =
 };
 #endif
 
-#if YYDEBUG || YYERROR_VERBOSE
-/* YYTNME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
+#if YYDEBUG || YYERROR_VERBOSE || YYTOKEN_TABLE
+/* YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
    First, the terminals, then, starting at YYNTOKENS, nonterminals. */
 static const char *const yytname[] =
 {
@@ -1444,22 +1502,6 @@ static const unsigned char yystos[] =
      206,   206
 };
 
-#if ! defined (YYSIZE_T) && defined (__SIZE_TYPE__)
-# define YYSIZE_T __SIZE_TYPE__
-#endif
-#if ! defined (YYSIZE_T) && defined (size_t)
-# define YYSIZE_T size_t
-#endif
-#if ! defined (YYSIZE_T)
-# if defined (__STDC__) || defined (__cplusplus)
-#  include <stddef.h> /* INFRINGES ON USER NAME SPACE */
-#  define YYSIZE_T size_t
-# endif
-#endif
-#if ! defined (YYSIZE_T)
-# define YYSIZE_T unsigned int
-#endif
-
 #define yyerrok		(yyerrstatus = 0)
 #define yyclearin	(yychar = YYEMPTY)
 #define YYEMPTY		(-2)
@@ -1489,8 +1531,8 @@ do								\
       goto yybackup;						\
     }								\
   else								\
-    { 								\
-      yyerror ("syntax error: cannot back up");\
+    {								\
+      yyerror (YY_("syntax error: cannot back up")); \
       YYERROR;							\
     }								\
 while (0)
@@ -1569,7 +1611,7 @@ do {								\
   if (yydebug)							\
     {								\
       YYFPRINTF (stderr, "%s ", Title);				\
-      yysymprint (stderr, 					\
+      yysymprint (stderr,					\
                   Type, Value);	\
       YYFPRINTF (stderr, "\n");					\
     }								\
@@ -1617,13 +1659,13 @@ yy_reduce_print (yyrule)
 #endif
 {
   int yyi;
-  unsigned int yylno = yyrline[yyrule];
-  YYFPRINTF (stderr, "Reducing stack by rule %d (line %u), ",
+  unsigned long int yylno = yyrline[yyrule];
+  YYFPRINTF (stderr, "Reducing stack by rule %d (line %lu), ",
              yyrule - 1, yylno);
   /* Print the symbols being reduced, and their result.  */
   for (yyi = yyprhs[yyrule]; 0 <= yyrhs[yyi]; yyi++)
-    YYFPRINTF (stderr, "%s ", yytname [yyrhs[yyi]]);
-  YYFPRINTF (stderr, "-> %s\n", yytname [yyr1[yyrule]]);
+    YYFPRINTF (stderr, "%s ", yytname[yyrhs[yyi]]);
+  YYFPRINTF (stderr, "-> %s\n", yytname[yyr1[yyrule]]);
 }
 
 # define YY_REDUCE_PRINT(Rule)		\
@@ -1652,7 +1694,7 @@ int yydebug;
    if the built-in stack extension method is used).
 
    Do not make this value too large; the results are undefined if
-   SIZE_MAX < YYSTACK_BYTES (YYMAXDEPTH)
+   YYSTACK_ALLOC_MAXIMUM < YYSTACK_BYTES (YYMAXDEPTH)
    evaluated with infinite-precision integer arithmetic.  */
 
 #ifndef YYMAXDEPTH
@@ -1676,7 +1718,7 @@ yystrlen (yystr)
      const char *yystr;
 #   endif
 {
-  register const char *yys = yystr;
+  const char *yys = yystr;
 
   while (*yys++ != '\0')
     continue;
@@ -1701,8 +1743,8 @@ yystpcpy (yydest, yysrc)
      const char *yysrc;
 #   endif
 {
-  register char *yyd = yydest;
-  register const char *yys = yysrc;
+  char *yyd = yydest;
+  const char *yys = yysrc;
 
   while ((*yyd++ = *yys++) != '\0')
     continue;
@@ -1712,7 +1754,55 @@ yystpcpy (yydest, yysrc)
 #  endif
 # endif
 
-#endif /* !YYERROR_VERBOSE */
+# ifndef yytnamerr
+/* Copy to YYRES the contents of YYSTR after stripping away unnecessary
+   quotes and backslashes, so that it's suitable for yyerror.  The
+   heuristic is that double-quoting is unnecessary unless the string
+   contains an apostrophe, a comma, or backslash (other than
+   backslash-backslash).  YYSTR is taken from yytname.  If YYRES is
+   null, do not copy; instead, return the length of what the result
+   would have been.  */
+static YYSIZE_T
+yytnamerr (char *yyres, const char *yystr)
+{
+  if (*yystr == '"')
+    {
+      size_t yyn = 0;
+      char const *yyp = yystr;
+
+      for (;;)
+	switch (*++yyp)
+	  {
+	  case '\'':
+	  case ',':
+	    goto do_not_strip_quotes;
+
+	  case '\\':
+	    if (*++yyp != '\\')
+	      goto do_not_strip_quotes;
+	    /* Fall through.  */
+	  default:
+	    if (yyres)
+	      yyres[yyn] = *yyp;
+	    yyn++;
+	    break;
+
+	  case '"':
+	    if (yyres)
+	      yyres[yyn] = '\0';
+	    return yyn;
+	  }
+    do_not_strip_quotes: ;
+    }
+
+  if (! yyres)
+    return yystrlen (yystr);
+
+  return yystpcpy (yyres, yystr) - yyres;
+}
+# endif
+
+#endif /* YYERROR_VERBOSE */
 
 
 
@@ -1832,13 +1922,13 @@ yyparse (void)
 #else
 int
 yyparse ()
-
+    ;
 #endif
 #endif
 {
   
-  register int yystate;
-  register int yyn;
+  int yystate;
+  int yyn;
   int yyresult;
   /* Number of tokens to shift before error messages enabled.  */
   int yyerrstatus;
@@ -1856,12 +1946,12 @@ yyparse ()
   /* The state stack.  */
   short int yyssa[YYINITDEPTH];
   short int *yyss = yyssa;
-  register short int *yyssp;
+  short int *yyssp;
 
   /* The semantic value stack.  */
   YYSTYPE yyvsa[YYINITDEPTH];
   YYSTYPE *yyvs = yyvsa;
-  register YYSTYPE *yyvsp;
+  YYSTYPE *yyvsp;
 
 
 
@@ -1893,9 +1983,6 @@ yyparse ()
   yyssp = yyss;
   yyvsp = yyvs;
 
-
-  yyvsp[0] = yylval;
-
   goto yysetstate;
 
 /*------------------------------------------------------------.
@@ -1928,7 +2015,7 @@ yyparse ()
 	   data in use in that stack, in bytes.  This used to be a
 	   conditional around just the two extra args, but that might
 	   be undefined if yyoverflow is a macro.  */
-	yyoverflow ("parser stack overflow",
+	yyoverflow (YY_("memory exhausted"),
 		    &yyss1, yysize * sizeof (*yyssp),
 		    &yyvs1, yysize * sizeof (*yyvsp),
 
@@ -1939,11 +2026,11 @@ yyparse ()
       }
 #else /* no yyoverflow */
 # ifndef YYSTACK_RELOCATE
-      goto yyoverflowlab;
+      goto yyexhaustedlab;
 # else
       /* Extend the stack our own way.  */
       if (YYMAXDEPTH <= yystacksize)
-	goto yyoverflowlab;
+	goto yyexhaustedlab;
       yystacksize *= 2;
       if (YYMAXDEPTH < yystacksize)
 	yystacksize = YYMAXDEPTH;
@@ -1953,7 +2040,7 @@ yyparse ()
 	union yyalloc *yyptr =
 	  (union yyalloc *) YYSTACK_ALLOC (YYSTACK_BYTES (yystacksize));
 	if (! yyptr)
-	  goto yyoverflowlab;
+	  goto yyexhaustedlab;
 	YYSTACK_RELOCATE (yyss);
 	YYSTACK_RELOCATE (yyvs);
 
@@ -4356,10 +4443,11 @@ yyreduce:
     break;
 
 
+      default: break;
     }
 
-/* Line 1037 of yacc.c.  */
-#line 4363 "y.tab.c"
+/* Line 1126 of yacc.c.  */
+#line 4451 "y.tab.c"
 
   yyvsp -= yylen;
   yyssp -= yylen;
@@ -4398,12 +4486,36 @@ yyerrlab:
 
       if (YYPACT_NINF < yyn && yyn < YYLAST)
 	{
-	  YYSIZE_T yysize = 0;
 	  int yytype = YYTRANSLATE (yychar);
-	  const char* yyprefix;
-	  char *yymsg;
+	  YYSIZE_T yysize0 = yytnamerr (0, yytname[yytype]);
+	  YYSIZE_T yysize = yysize0;
+	  YYSIZE_T yysize1;
+	  int yysize_overflow = 0;
+	  char *yymsg = 0;
+#	  define YYERROR_VERBOSE_ARGS_MAXIMUM 5
+	  char const *yyarg[YYERROR_VERBOSE_ARGS_MAXIMUM];
 	  int yyx;
 
+#if 0
+	  /* This is so xgettext sees the translatable formats that are
+	     constructed on the fly.  */
+	  YY_("syntax error, unexpected %s");
+	  YY_("syntax error, unexpected %s, expecting %s");
+	  YY_("syntax error, unexpected %s, expecting %s or %s");
+	  YY_("syntax error, unexpected %s, expecting %s or %s or %s");
+	  YY_("syntax error, unexpected %s, expecting %s or %s or %s or %s");
+#endif
+	  char *yyfmt;
+	  char const *yyf;
+	  static char const yyunexpected[] = "syntax error, unexpected %s";
+	  static char const yyexpecting[] = ", expecting %s";
+	  static char const yyor[] = " or %s";
+	  char yyformat[sizeof yyunexpected
+			+ sizeof yyexpecting - 1
+			+ ((YYERROR_VERBOSE_ARGS_MAXIMUM - 2)
+			   * (sizeof yyor - 1))];
+	  char const *yyprefix = yyexpecting;
+
 	  /* Start YYX at -YYN if negative to avoid negative indexes in
 	     YYCHECK.  */
 	  int yyxbegin = yyn < 0 ? -yyn : 0;
@@ -4411,48 +4523,68 @@ yyerrlab:
 	  /* Stay within bounds of both yycheck and yytname.  */
 	  int yychecklim = YYLAST - yyn;
 	  int yyxend = yychecklim < YYNTOKENS ? yychecklim : YYNTOKENS;
-	  int yycount = 0;
+	  int yycount = 1;
+
+	  yyarg[0] = yytname[yytype];
+	  yyfmt = yystpcpy (yyformat, yyunexpected);
 
-	  yyprefix = ", expecting ";
 	  for (yyx = yyxbegin; yyx < yyxend; ++yyx)
 	    if (yycheck[yyx + yyn] == yyx && yyx != YYTERROR)
 	      {
-		yysize += yystrlen (yyprefix) + yystrlen (yytname [yyx]);
-		yycount += 1;
-		if (yycount == 5)
+		if (yycount == YYERROR_VERBOSE_ARGS_MAXIMUM)
 		  {
-		    yysize = 0;
+		    yycount = 1;
+		    yysize = yysize0;
+		    yyformat[sizeof yyunexpected - 1] = '\0';
 		    break;
 		  }
+		yyarg[yycount++] = yytname[yyx];
+		yysize1 = yysize + yytnamerr (0, yytname[yyx]);
+		yysize_overflow |= yysize1 < yysize;
+		yysize = yysize1;
+		yyfmt = yystpcpy (yyfmt, yyprefix);
+		yyprefix = yyor;
 	      }
-	  yysize += (sizeof ("syntax error, unexpected ")
-		     + yystrlen (yytname[yytype]));
-	  yymsg = (char *) YYSTACK_ALLOC (yysize);
-	  if (yymsg != 0)
-	    {
-	      char *yyp = yystpcpy (yymsg, "syntax error, unexpected ");
-	      yyp = yystpcpy (yyp, yytname[yytype]);
 
-	      if (yycount < 5)
+	  yyf = YY_(yyformat);
+	  yysize1 = yysize + yystrlen (yyf);
+	  yysize_overflow |= yysize1 < yysize;
+	  yysize = yysize1;
+
+	  if (!yysize_overflow && yysize <= YYSTACK_ALLOC_MAXIMUM)
+	    yymsg = (char *) YYSTACK_ALLOC (yysize);
+	  if (yymsg)
+	    {
+	      /* Avoid sprintf, as that infringes on the user's name space.
+		 Don't have undefined behavior even if the translation
+		 produced a string with the wrong number of "%s"s.  */
+	      char *yyp = yymsg;
+	      int yyi = 0;
+	      while ((*yyp = *yyf))
 		{
-		  yyprefix = ", expecting ";
-		  for (yyx = yyxbegin; yyx < yyxend; ++yyx)
-		    if (yycheck[yyx + yyn] == yyx && yyx != YYTERROR)
-		      {
-			yyp = yystpcpy (yyp, yyprefix);
-			yyp = yystpcpy (yyp, yytname[yyx]);
-			yyprefix = " or ";
-		      }
+		  if (*yyp == '%' && yyf[1] == 's' && yyi < yycount)
+		    {
+		      yyp += yytnamerr (yyp, yyarg[yyi++]);
+		      yyf += 2;
+		    }
+		  else
+		    {
+		      yyp++;
+		      yyf++;
+		    }
 		}
 	      yyerror (yymsg);
 	      YYSTACK_FREE (yymsg);
 	    }
 	  else
-	    yyerror ("syntax error; also virtual memory exhausted");
+	    {
+	      yyerror (YY_("syntax error"));
+	      goto yyexhaustedlab;
+	    }
 	}
       else
 #endif /* YYERROR_VERBOSE */
-	yyerror ("syntax error");
+	yyerror (YY_("syntax error"));
     }
 
 
@@ -4464,18 +4596,9 @@ yyerrlab:
 
       if (yychar <= YYEOF)
         {
-          /* If at end of input, pop the error token,
-	     then the rest of the stack, then return failure.  */
+	  /* Return failure if at end of input.  */
 	  if (yychar == YYEOF)
-	     for (;;)
-	       {
-
-		 YYPOPSTACK;
-		 if (yyssp == yyss)
-		   YYABORT;
-		 yydestruct ("Error: popping",
-                             yystos[*yyssp], yyvsp);
-	       }
+	    YYABORT;
         }
       else
 	{
@@ -4494,12 +4617,11 @@ yyerrlab:
 `---------------------------------------------------*/
 yyerrorlab:
 
-#ifdef __GNUC__
-  /* Pacify GCC when the user code never invokes YYERROR and the label
-     yyerrorlab therefore never appears in user code.  */
+  /* Pacify compilers like GCC when the user code never invokes
+     YYERROR and the label yyerrorlab therefore never appears in user
+     code.  */
   if (0)
      goto yyerrorlab;
-#endif
 
 yyvsp -= yylen;
   yyssp -= yylen;
@@ -4562,23 +4684,29 @@ yyacceptlab:
 | yyabortlab -- YYABORT comes here.  |
 `-----------------------------------*/
 yyabortlab:
-  yydestruct ("Error: discarding lookahead",
-              yytoken, &yylval);
-  yychar = YYEMPTY;
   yyresult = 1;
   goto yyreturn;
 
 #ifndef yyoverflow
-/*----------------------------------------------.
-| yyoverflowlab -- parser overflow comes here.  |
-`----------------------------------------------*/
-yyoverflowlab:
-  yyerror ("parser stack overflow");
+/*-------------------------------------------------.
+| yyexhaustedlab -- memory exhaustion comes here.  |
+`-------------------------------------------------*/
+yyexhaustedlab:
+  yyerror (YY_("memory exhausted"));
   yyresult = 2;
   /* Fall through.  */
 #endif
 
 yyreturn:
+  if (yychar != YYEOF && yychar != YYEMPTY)
+     yydestruct ("Cleanup: discarding lookahead",
+		 yytoken, &yylval);
+  while (yyssp != yyss)
+    {
+      yydestruct ("Cleanup: popping",
+		  yystos[*yyssp], yyvsp);
+      YYPOPSTACK;
+    }
 #ifndef yyoverflow
   if (yyss != yyssa)
     YYSTACK_FREE (yyss);
diff --git a/panda/src/egg/parser.h.prebuilt b/panda/src/egg/parser.h.prebuilt
index 58b83cc12a..e0087d67a1 100644
--- a/panda/src/egg/parser.h.prebuilt
+++ b/panda/src/egg/parser.h.prebuilt
@@ -1,7 +1,7 @@
-/* A Bison parser, made by GNU Bison 2.0.  */
+/* A Bison parser, made by GNU Bison 2.1.  */
 
 /* Skeleton parser for Yacc-like parsing with Bison,
-   Copyright (C) 1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
+   Copyright (C) 1984, 1989, 1990, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -15,8 +15,8 @@
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
-   Foundation, Inc., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
+   Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
 
 /* As a special exception, when this file is copied by Bison into a
    Bison output file, you may use that output file without restriction.
@@ -119,6 +119,7 @@
      START_PRIMITIVE_BODY = 345
    };
 #endif
+/* Tokens.  */
 #define EGG_NUMBER 258
 #define EGG_ULONG 259
 #define EGG_STRING 260
diff --git a/panda/src/egg/parserDefs.h b/panda/src/egg/parserDefs.h
index 8aa6a11fe3..0318104abe 100644
--- a/panda/src/egg/parserDefs.h
+++ b/panda/src/egg/parserDefs.h
@@ -30,6 +30,9 @@
 #include <string>
 
 class EggGroupNode;
+class Mutex;
+
+extern Mutex egg_lock;
 
 void egg_init_parser(istream &in, const string &filename,
                      EggObject *tos, EggGroupNode *egg_top_node);