diff --git a/Makefile b/Makefile
index 9263dd08..e5947569 100644
--- a/Makefile
+++ b/Makefile
@@ -174,6 +174,10 @@ core/potion.o: core/potion.c core/potion.h core/config.h core/internal.h \
  core/opcodes.h core/khash.h core/table.h
 	@${ECHO} CC $@ -O0
 	@${CC} -c ${CFLAGS} -O0 ${INCS} -o $@ $<
+core/syntax.o: core/syntax.c core/potion.h core/config.h core/internal.h \
+ core/asm.h core/ast.h tools/greg.h
+	@${ECHO} CC $@
+	@${CC} -c ${CFLAGS} ${INCS} -Itools -o $@ $<
 ifneq (${FPIC},)
 core/callcc.${OPIC}: core/callcc.c core/potion.h core/config.h core/internal.h
 	@${ECHO} CC $@ -O0 +frame-pointer
@@ -182,6 +186,10 @@ core/potion.${OPIC}: core/potion.c core/potion.h core/config.h core/internal.h \
  core/opcodes.h core/khash.h core/table.h
 	@${ECHO} CC $@ -O0
 	@${CC} -c ${CFLAGS} -O0 ${FPIC} ${INCS} -o $@ $<
+core/syntax.${OPIC}: core/syntax.c core/potion.h core/config.h core/internal.h \
+ core/asm.h core/ast.h tools/greg.h
+	@${ECHO} CC $@
+	@${CC} -c ${CFLAGS} ${FPIC} ${INCS} -Itools -o $@ $<
 endif
 
 core/potion.h: core/config.h
@@ -259,7 +267,7 @@ endif
 
 ${GREG}: tools/greg.c tools/compile.c tools/tree.c
 	@${ECHO} CC $@
-	@${CC} ${GREGCFLAGS} -o $@ tools/greg.c tools/compile.c tools/tree.c -Itools
+	@${CC} ${GREGCFLAGS} -Itools -o $@ tools/greg.c tools/compile.c tools/tree.c
 
 bin/potion${EXE}: ${PIC_OBJ_POTION} lib/libpotion${DLL}
 	@${ECHO} LINK $@
diff --git a/core/gc.c b/core/gc.c
index d610985a..30e05050 100644
--- a/core/gc.c
+++ b/core/gc.c
@@ -14,6 +14,7 @@ by Basile Starynkevitch.
 #include "gc.h"
 #include "khash.h"
 #include "table.h"
+#include "../tools/greg.h"
 
 #if defined(DEBUG)
 //mingw32 has struct timeval in sys/time.h
@@ -133,6 +134,56 @@ static inline int NEW_BIRTH_REGION(struct PNMemory *M, void **wb, int sz) {
   return sz;
 }
 
+void potion_gc_minor_parser(PN parser) {
+  if(parser == 0)
+    return;
+
+  struct _GREG *G = (struct _GREG *)parser;
+  struct PNMemory *M = ((Potion *)G->data)->mem;
+  Potion *P = G->data;
+
+  if(PN_IS_PTR(G->ss)) {
+    GC_MINOR_UPDATE(G->ss);
+    potion_mark_minor(G->data, (const struct PNObject *) G->ss);
+  }
+  if(PN_IS_PTR(G->val[0])) {
+    GC_MINOR_UPDATE(G->val[0]);
+    potion_mark_minor(G->data, (const struct PNObject *) G->val[0]);
+  }
+  int c = G->val - G->vals;
+  for(int i = 0; i < c; i++) {
+    if(PN_IS_PTR(G->vals[i])) {
+      GC_MINOR_UPDATE(G->vals[i]);
+      potion_mark_minor(G->data, (const struct PNObject *) G->vals[i]);
+    }
+  }
+}
+
+void potion_gc_major_parser(PN parser) {
+  if(parser == 0)
+    return;
+
+  struct _GREG *G = (struct _GREG *)parser;
+  struct PNMemory *M = ((Potion *)G->data)->mem;
+  Potion *P = G->data;
+
+  if(PN_IS_PTR(G->ss)) {
+    GC_MAJOR_UPDATE(G->ss);
+    potion_mark_major(P, (const struct PNObject *) G->ss);
+  }
+  if(PN_IS_PTR(G->val[0])) {
+    GC_MAJOR_UPDATE(G->val[0]);
+    potion_mark_major(P, (const struct PNObject *) G->val[0]);
+  }
+  int c = G->val - G->vals;
+  for(int i = 0; i < c; i++) {
+    if(G->vals[i] != NULL && PN_IS_PTR(G->vals[i])) {
+      GC_MAJOR_UPDATE(G->vals[i]);
+      potion_mark_major(P, (const struct PNObject *) G->vals[i]);
+    }
+  }
+}
+
 /** \par
   Both this function and potion_gc_major embody a simple
   Cheney loop (also called a "two-finger collector.")
@@ -161,6 +212,7 @@ static int potion_gc_minor(Potion *P, int sz) {
   potion_mark_stack(P, 1);
 
   GC_MINOR_STRINGS();
+  potion_gc_minor_parser(P->parser);
 
   wb = (void **)M->birth_storeptr;
   for (storead = wb; storead < (void **)M->birth_hi; storead++) {
@@ -239,6 +291,7 @@ static int potion_gc_major(Potion *P, int siz) {
   scanptr = 0;
 
   GC_MAJOR_STRINGS();
+  potion_gc_minor_parser(P->parser);
 
   pngc_page_delete((void *)prevoldlo, (char *)prevoldhi - (char *)prevoldlo);
   prevoldlo = 0;
diff --git a/core/potion.h b/core/potion.h
index 008754eb..cc4aee50 100644
--- a/core/potion.h
+++ b/core/potion.h
@@ -653,7 +653,7 @@ struct Potion_State {
   int prec;                ///< double precision
 
   //parser-only:
-  PN input, source;        ///< parser input and output (AST)
+  PN input, source, parser;///< parser input and output (AST)
   int yypos;               ///< parser buffer position
   PNAsm * volatile pbuf;   ///< parser buffer
   PN line;                 ///< currently parsed line (for debug)
diff --git a/core/syntax.y b/core/syntax.y
index c77bc0f8..d9dc9277 100644
--- a/core/syntax.y
+++ b/core/syntax.y
@@ -387,6 +387,7 @@ PN potion_parse(Potion *P, PN code, char *filename) {
   P->yypos = 0;
   P->input = code;
   P->source = PN_NIL;
+  P->parser = (PN)G;
   P->pbuf = potion_asm_new(P);
 #ifdef YY_DEBUG
   yydebug = P->flags;
@@ -449,6 +450,7 @@ PN potion_sig(Potion *P, char *fmt) {
   P->yypos = 0;
   P->input = potion_byte_str(P, fmt);
   P->source = out = PN_TUP0();
+  P->parser = (PN)G;
   P->pbuf = NULL;
 #ifdef YY_DEBUG
   yydebug = P->flags;
diff --git a/tools/compile.c b/tools/compile.c
index 9d7e3596..5a0d103d 100644
--- a/tools/compile.c
+++ b/tools/compile.c
@@ -1,6 +1,6 @@
 /* Copyright (c) 2007 by Ian Piumarta
  * Copyright (c) 2011 by Amos Wenger nddrylliog@gmail.com
- * Copyright (c) 2013 by perl11 org
+ * Copyright (c) 2013,2019 by perl11 org
  * All rights reserved.
  * 
  * Permission is hereby granted, free of charge, to any person obtaining a
@@ -470,7 +470,7 @@ static char *header= "\
 #include <stdio.h>\n\
 #include <stdlib.h>\n\
 #include <string.h>\n\
-struct _GREG;\n\
+#include \"greg.h\"\n\
 ";
 
 static char *preamble= "\
@@ -564,12 +564,6 @@ static char *preamble= "\
 # define yyprintfvokrule(rule)\n\
 # define yyprintfvfailrule(rule)\n\
 #endif\n\
-#ifndef YYSTYPE\n\
-#define YYSTYPE	int\n\
-#endif\n\
-#ifndef YY_XTYPE\n\
-#define YY_XTYPE void *\n\
-#endif\n\
 #ifndef YY_XVAR\n\
 #define YY_XVAR yyxvar\n\
 #endif\n\
@@ -586,35 +580,9 @@ static char *preamble= "\
 #define yydata G->data\n\
 #define yy G->ss\n\
 \n\
-struct _yythunk; // forward declaration\n\
 typedef void (*yyaction)(struct _GREG *G, char *yytext, int yyleng, struct _yythunk *thunkpos, YY_XTYPE YY_XVAR);\n\
 typedef struct _yythunk { int begin, end;  yyaction  action; const char *name; struct _yythunk *next; } yythunk;\n\
 \n\
-typedef struct _GREG {\n\
-  char *buf;\n\
-  int   buflen;\n\
-  int   offset;\n\
-  int   pos;\n\
-  int   limit;\n\
-  char *text;\n\
-  int	textlen;\n\
-  int	begin;\n\
-  int	end;\n\
-  yythunk *thunks;\n\
-  int	thunkslen;\n\
-  int   thunkpos;\n\
-  int	lineno;\n\
-  char	*filename;\n\
-  FILE  *input;\n\
-  YYSTYPE ss;\n\
-  YYSTYPE *val;\n\
-  YYSTYPE *vals;\n\
-  int valslen;\n\
-  YY_XTYPE data;\n\
-#ifdef YY_DEBUG\n\
-  int debug;\n\
-#endif\n\
-} GREG;\n\
 \n\
 YY_LOCAL(int) yyrefill(GREG *G)\n\
 {\n\
@@ -925,7 +893,8 @@ YY_PARSE(void) YY_NAME(parse_free)(GREG *G)\n\
 
 void Rule_compile_c_header(void)
 {
-  fprintf(output, "/* A recursive-descent parser generated by greg %d.%d.%d */\n", GREG_MAJOR, GREG_MINOR, GREG_LEVEL);
+  fprintf(output, "/* A recursive-descent parser generated by greg %d.%d.%d */\n",
+          GREG_MAJOR, GREG_MINOR, GREG_LEVEL);
   fprintf(output, "\n");
   fprintf(output, "%s", header);
   fprintf(output, "#define YYRULECOUNT %d\n", ruleCount);
diff --git a/tools/greg.c b/tools/greg.c
index 390e8e7e..67b1bc0d 100644
--- a/tools/greg.c
+++ b/tools/greg.c
@@ -1,9 +1,8 @@
-/* A recursive-descent parser generated by greg 0.4.5 */
+/* A recursive-descent parser generated by greg 0.4.6 */
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-struct _GREG;
 #define YYRULECOUNT 38
 
 # include "greg.h"
@@ -129,12 +128,6 @@ int main()\n\
 # define yyprintfvokrule(rule)
 # define yyprintfvfailrule(rule)
 #endif
-#ifndef YYSTYPE
-#define YYSTYPE	int
-#endif
-#ifndef YY_XTYPE
-#define YY_XTYPE void *
-#endif
 #ifndef YY_XVAR
 #define YY_XVAR yyxvar
 #endif
@@ -151,35 +144,9 @@ int main()\n\
 #define yydata G->data
 #define yy G->ss
 
-struct _yythunk; // forward declaration
 typedef void (*yyaction)(struct _GREG *G, char *yytext, int yyleng, struct _yythunk *thunkpos, YY_XTYPE YY_XVAR);
 typedef struct _yythunk { int begin, end;  yyaction  action; const char *name; struct _yythunk *next; } yythunk;
 
-typedef struct _GREG {
-  char *buf;
-  int   buflen;
-  int   offset;
-  int   pos;
-  int   limit;
-  char *text;
-  int	textlen;
-  int	begin;
-  int	end;
-  yythunk *thunks;
-  int	thunkslen;
-  int   thunkpos;
-  int	lineno;
-  char	*filename;
-  FILE  *input;
-  YYSTYPE ss;
-  YYSTYPE *val;
-  YYSTYPE *vals;
-  int valslen;
-  YY_XTYPE data;
-#ifdef YY_DEBUG
-  int debug;
-#endif
-} GREG;
 
 YY_LOCAL(int) yyrefill(GREG *G)
 {
@@ -284,7 +251,7 @@ YY_LOCAL(int) yymatchString(GREG *G, const char *s)
   return 1;
 }
 
-YY_LOCAL(int) yymatchClass(GREG *G, const unsigned char *bits, char *cclass)
+YY_LOCAL(int) yymatchClass(GREG *G, unsigned char *bits, char *cclass)
 {
   int c;
   if (G->pos >= G->limit && !yyrefill(G)) return 0;
@@ -799,35 +766,35 @@ YY_RULE(int) yy_char(GREG *G)
   {
     int yypos23= G->pos, yythunkpos23= G->thunkpos;
     if (!yymatchChar(G, '\\')) goto l24;
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\204\040\000\000\000\000\000\070\146\100\124\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "-abefnrtv'\"\\[\\]\\\\")) goto l24;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\204\040\000\000\000\000\000\070\146\100\124\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "-abefnrtv'\"\\[\\]\\\\")) goto l24;
     goto l23;
     l24:
     G->pos= yypos23; G->thunkpos= yythunkpos23;
     if (!yymatchChar(G, '\\')) goto l25;
     if (!yymatchChar(G, 'x')) goto l25;
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\000\000\377\003\176\000\000\000\176\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-9A-Fa-f")) goto l25;
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\000\000\377\003\176\000\000\000\176\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-9A-Fa-f")) goto l25;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\000\000\377\003\176\000\000\000\176\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-9A-Fa-f")) goto l25;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\000\000\377\003\176\000\000\000\176\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-9A-Fa-f")) goto l25;
     goto l23;
     l25:
     G->pos= yypos23; G->thunkpos= yythunkpos23;
     if (!yymatchChar(G, '\\')) goto l26;
     if (!yymatchChar(G, 'x')) goto l26;
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\000\000\377\003\176\000\000\000\176\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-9A-Fa-f")) goto l26;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\000\000\377\003\176\000\000\000\176\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-9A-Fa-f")) goto l26;
     goto l23;
     l26:
     G->pos= yypos23; G->thunkpos= yythunkpos23;
     if (!yymatchChar(G, '\\')) goto l27;
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\000\000\017\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-3")) goto l27;
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\000\000\377\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-7")) goto l27;
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\000\000\377\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-7")) goto l27;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\000\000\017\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-3")) goto l27;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\000\000\377\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-7")) goto l27;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\000\000\377\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-7")) goto l27;
     goto l23;
     l27:
     G->pos= yypos23; G->thunkpos= yythunkpos23;
     if (!yymatchChar(G, '\\')) goto l28;
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\000\000\377\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-7")) goto l28;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\000\000\377\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-7")) goto l28;
     {
       int yypos30= G->pos, yythunkpos30= G->thunkpos;
-      if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\000\000\377\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-7")) goto l30;
+      if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\000\000\377\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "0-7")) goto l30;
       goto l29;
       l30:
       G->pos= yypos30; G->thunkpos= yythunkpos30;
@@ -950,7 +917,7 @@ YY_RULE(int) yy_literal(GREG *G)
   yyprintfv((stderr, "%s\n", "literal"));
   {
     int yypos40= G->pos, yythunkpos40= G->thunkpos;
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "'")) goto l41;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "'")) goto l41;
     yyText(G, G->begin, G->end);
     {
       #define yytext G->text
@@ -966,7 +933,7 @@ YY_RULE(int) yy_literal(GREG *G)
       int yypos43= G->pos, yythunkpos43= G->thunkpos;
       {
         int yypos44= G->pos, yythunkpos44= G->thunkpos;
-        if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "'")) goto l44;
+        if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "'")) goto l44;
         goto l43;
         l44:
         G->pos= yypos44; G->thunkpos= yythunkpos44;
@@ -985,12 +952,12 @@ YY_RULE(int) yy_literal(GREG *G)
       #undef yyleng
     }
 
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "'")) goto l41;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\200\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "'")) goto l41;
     if (!yy__(G))     goto l41;
     goto l40;
     l41:
     G->pos= yypos40; G->thunkpos= yythunkpos40;
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "\"")) goto l39;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "\"")) goto l39;
     yyText(G, G->begin, G->end);
     {
       #define yytext G->text
@@ -1006,7 +973,7 @@ YY_RULE(int) yy_literal(GREG *G)
       int yypos46= G->pos, yythunkpos46= G->thunkpos;
       {
         int yypos47= G->pos, yythunkpos47= G->thunkpos;
-        if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "\"")) goto l47;
+        if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "\"")) goto l47;
         goto l46;
         l47:
         G->pos= yypos47; G->thunkpos= yythunkpos47;
@@ -1025,7 +992,7 @@ YY_RULE(int) yy_literal(GREG *G)
       #undef yyleng
     }
 
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "\"")) goto l39;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\004\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "\"")) goto l39;
     if (!yy__(G))     goto l39;
   }
 
@@ -1469,12 +1436,12 @@ YY_RULE(int) yy_identifier(GREG *G)
     #undef yyleng
   }
 
-  if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\000\040\000\000\376\377\377\207\376\377\377\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "-a-zA-Z_")) goto l95;
+  if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\000\040\000\000\376\377\377\207\376\377\377\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "-a-zA-Z_")) goto l95;
 
   l96:
   {
     int yypos97= G->pos, yythunkpos97= G->thunkpos;
-    if (!yymatchClass(G, (const unsigned char *)"\000\000\000\000\000\040\377\003\376\377\377\207\376\377\377\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "-a-zA-Z_0-9")) goto l97;
+    if (!yymatchClass(G, (unsigned char *)"\000\000\000\000\000\040\377\003\376\377\377\207\376\377\377\007\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000\000", "-a-zA-Z_0-9")) goto l97;
     goto l96;
     l97:
     G->pos= yypos97; G->thunkpos= yythunkpos97;
@@ -1729,18 +1696,19 @@ typedef int (*yyrule)(GREG *G);
 YY_PARSE(int) YY_NAME(parse_from)(GREG *G, yyrule yystart)
 {
   int yyok;
-  if (!G->buflen) {
-    G->buflen= YY_BUFFER_START_SIZE;
-    G->buf= (char*)YY_ALLOC(G->buflen, G->data);
-    G->textlen= YY_BUFFER_START_SIZE;
-    G->text= (char*)YY_ALLOC(G->textlen, G->data);
-    G->thunkslen= YY_STACK_SIZE;
-    G->thunks= (yythunk*)YY_ALLOC(sizeof(yythunk) * G->thunkslen, G->data);
-    G->valslen= YY_STACK_SIZE;
-    G->vals= (YYSTYPE*)YY_ALLOC(sizeof(YYSTYPE) * G->valslen, G->data);
-    G->begin= G->end= G->pos= G->limit= G->thunkpos= 0;
-  }
-  G->pos= 0;
+  if (!G->buflen)
+    {
+      G->buflen= YY_BUFFER_START_SIZE;
+      G->buf= (char*)YY_ALLOC(G->buflen, G->data);
+      G->textlen= YY_BUFFER_START_SIZE;
+      G->text= (char*)YY_ALLOC(G->textlen, G->data);
+      G->thunkslen= YY_STACK_SIZE;
+      G->thunks= (yythunk*)YY_ALLOC(sizeof(yythunk) * G->thunkslen, G->data);
+      G->valslen= YY_STACK_SIZE;
+      G->vals= (YYSTYPE*)YY_ALLOC(sizeof(YYSTYPE) * G->valslen, G->data);
+      G->begin= G->end= G->pos= G->limit= G->thunkpos= 0;
+    }
+  G->pos = 0;
   G->begin= G->end= G->pos;
   G->thunkpos= 0;
   G->val= G->vals;
@@ -1748,7 +1716,6 @@ YY_PARSE(int) YY_NAME(parse_from)(GREG *G, yyrule yystart)
   if (yyok) yyDone(G);
   yyCommit(G);
   return yyok;
-  
   (void)yyrefill;
   (void)yymatchDot;
   (void)yymatchChar;
diff --git a/tools/greg.h b/tools/greg.h
index 43b24823..16a1cd4d 100644
--- a/tools/greg.h
+++ b/tools/greg.h
@@ -15,7 +15,7 @@
  * 
  * THE SOFTWARE IS PROVIDED 'AS IS'.  USE ENTIRELY AT YOUR OWN RISK.
  * 
- * Last edited: 2013-04-11 11:10:34 rurban
+ * Last edited: 2019-02-06 12:05:37 rurban
  */
 
 #include <stdio.h>
@@ -26,9 +26,11 @@
 
 #define GREG_MAJOR	0
 #define GREG_MINOR	4
-#define GREG_LEVEL	5
+#define GREG_LEVEL	6
 
-typedef enum { Freed = -1, Unknown= 0, Rule, Variable, Name, Dot, Character, String, Class, Action, Predicate, Error, Alternate, Sequence, PeekFor, PeekNot, Query, Star, Plus, Any } NodeType;
+typedef enum { Freed = -1, Unknown= 0, Rule, Variable, Name, Dot, Character, String,
+               Class, Action, Predicate, Error, Alternate, Sequence, PeekFor, PeekNot,
+               Query, Star, Plus, Any } NodeType;
 
 enum {
   RuleUsed	= 1<<0,
@@ -38,26 +40,59 @@ enum {
 typedef union Node Node;
 
 #define NODE_COMMON NodeType type;  Node *next
-struct Rule	 { NODE_COMMON; char *name; Node *variables;  Node *expression;  int id;  int flags;	};
-struct Variable	 { NODE_COMMON; char *name; Node *value;  int offset;					};
-struct Name	 { NODE_COMMON; Node *rule; Node *variable;						};
-struct Dot	 { NODE_COMMON;										};
-struct Character { NODE_COMMON; char *value;								};
-struct String	 { NODE_COMMON; char *value;								};
-struct Class	 { NODE_COMMON; unsigned char *value;							};
-struct Action	 { NODE_COMMON; char *text;  Node *list;  char *name;  Node *rule;			};
-struct Predicate { NODE_COMMON; char *text;								};
-struct Error     { NODE_COMMON; Node *element; char *text;						};
-struct Alternate { NODE_COMMON; Node *first;  Node *last;						};
-struct Sequence	 { NODE_COMMON; Node *first;  Node *last;						};
-struct PeekFor	 { NODE_COMMON; Node *element;								};
-struct PeekNot	 { NODE_COMMON; Node *element;								};
-struct Query	 { NODE_COMMON; Node *element;								};
-struct Star	 { NODE_COMMON; Node *element;								};
-struct Plus	 { NODE_COMMON; Node *element;								};
-struct Any	 { NODE_COMMON;										};
+struct Rule	 { NODE_COMMON; char *name; Node *variables; Node *expression; int id; int flags; };
+struct Variable	 { NODE_COMMON; char *name; Node *value;  int offset;		   };
+struct Name	 { NODE_COMMON; Node *rule; Node *variable;			   };
+struct Dot	 { NODE_COMMON;							   };
+struct Character { NODE_COMMON; char *value;					   };
+struct String	 { NODE_COMMON; char *value;					   };
+struct Class	 { NODE_COMMON; unsigned char *value;				   };
+struct Action	 { NODE_COMMON; char *text;  Node *list;  char *name;  Node *rule; };
+struct Predicate { NODE_COMMON; char *text;					   };
+struct Error     { NODE_COMMON; Node *element; char *text;			   };
+struct Alternate { NODE_COMMON; Node *first;  Node *last;			   };
+struct Sequence	 { NODE_COMMON; Node *first;  Node *last;			   };
+struct PeekFor	 { NODE_COMMON; Node *element;					   };
+struct PeekNot	 { NODE_COMMON; Node *element;					   };
+struct Query	 { NODE_COMMON; Node *element;					   };
+struct Star	 { NODE_COMMON; Node *element;					   };
+struct Plus	 { NODE_COMMON; Node *element;					   };
+struct Any	 { NODE_COMMON;							   };
 #undef NODE_COMMON
 
+#ifndef YYSTYPE
+#define YYSTYPE	int
+#endif
+#ifndef YY_XTYPE
+#define YY_XTYPE void *
+#endif
+struct _yythunk; // forward declaration
+typedef struct _GREG {
+  char *buf;
+  int   buflen;
+  int   offset;
+  int   pos;
+  int   limit;
+  char *text;
+  int	textlen;
+  int	begin;
+  int	end;
+  struct _yythunk *thunks;
+  int	thunkslen;
+  int   thunkpos;
+  int	lineno;
+  char	*filename;
+  FILE  *input;
+  YYSTYPE ss;
+  YYSTYPE *val;
+  YYSTYPE *vals;
+  int valslen;
+  YY_XTYPE data;
+#ifdef YY_DEBUG
+  int debug;
+#endif
+} GREG;
+
 union Node
 {
   NodeType		type;