--- a/absyntax/absyntax.cc	Thu Apr 14 17:35:25 2011 +0100
+++ b/absyntax/absyntax.cc	Thu Apr 14 18:12:59 2011 +0100
@@ -50,22 +50,24 @@
 
 /* The base class of all symbols */
 symbol_c::symbol_c(
-                   int first_line, int first_column, const char *ffile,
-                   int last_line,  int last_column,  const char *lfile) {
+                   int first_line, int first_column, const char *ffile, long int first_order,
+                   int last_line,  int last_column,  const char *lfile, long int last_order ) {
   this->first_file   = ffile,
   this->first_line   = first_line;
   this->first_column = first_column;
+  this->first_order  = first_order;
   this->last_file    = lfile,
   this->last_line    = last_line;
   this->last_column  = last_column;
+  this->last_order   = last_order;
 }
 
 
 
 token_c::token_c(const char *value, 
-                 int fl, int fc, const char *ffile,
-                 int ll, int lc, const char *lfile)
-  :symbol_c(fl, fc, ffile, ll, lc, lfile) {
+                 int fl, int fc, const char *ffile, long int forder,
+                 int ll, int lc, const char *lfile, long int lorder)
+  :symbol_c(fl, fc, ffile, forder, ll, lc, lfile, lorder) {
   this->value = value;
 //  printf("New token: %s\n", value);
 }
@@ -76,17 +78,17 @@
 
 
 list_c::list_c(
-               int fl, int fc, const char *ffile,
-               int ll, int lc, const char *lfile)
-  :symbol_c(fl, fc, ffile, ll, lc, lfile) {
+               int fl, int fc, const char *ffile, long int forder,
+               int ll, int lc, const char *lfile, long int lorder)
+  :symbol_c(fl, fc, ffile, forder, ll, lc, lfile, lorder) {
   n = 0;
   elements = NULL;
 }
 
 list_c::list_c(symbol_c *elem, 
-               int fl, int fc, const char *ffile,
-               int ll, int lc, const char *lfile)
-  :symbol_c(fl, fc, ffile, ll, lc, lfile) {
+               int fl, int fc, const char *ffile, long int forder,
+               int ll, int lc, const char *lfile, long int lorder)
+  :symbol_c(fl, fc, ffile, forder, ll, lc, lfile, lorder) {
   n = 0;
   elements = NULL;
   add_element(elem);
@@ -128,35 +130,35 @@
 
 #define SYM_LIST(class_name_c)									\
 class_name_c::class_name_c(									\
-                           int fl, int fc, const char *ffile,					\
-                           int ll, int lc, const char *lfile)					\
-                        :list_c(fl, fc, ffile, ll, lc, lfile) {}				\
+                           int fl, int fc, const char *ffile, long int forder,			\
+                           int ll, int lc, const char *lfile, long int lorder)			\
+                        :list_c(fl, fc, ffile, forder, ll, lc, lfile, lorder) {}		\
 class_name_c::class_name_c(symbol_c *elem, 							\
-                           int fl, int fc, const char *ffile,					\
-                           int ll, int lc, const char *lfile)					\
-			:list_c(elem, fl, fc, ffile, ll, lc, lfile) {}				\
+                           int fl, int fc, const char *ffile, long int forder,			\
+                           int ll, int lc, const char *lfile, long int lorder)			\
+			:list_c(elem, fl, fc, ffile, forder, ll, lc, lfile, lorder) {}		\
 void *class_name_c::accept(visitor_c &visitor) {return visitor.visit(this);}
 
 #define SYM_TOKEN(class_name_c)									\
 class_name_c::class_name_c(const char *value, 							\
-                           int fl, int fc, const char *ffile,					\
-                           int ll, int lc, const char *lfile)					\
-			:token_c(value, fl, fc, ffile, ll, lc, lfile) {}			\
+                           int fl, int fc, const char *ffile, long int forder,			\
+                           int ll, int lc, const char *lfile, long int lorder)			\
+			:token_c(value, fl, fc, ffile, forder, ll, lc, lfile, lorder) {}	\
 void *class_name_c::accept(visitor_c &visitor) {return visitor.visit(this);}
 
 #define SYM_REF0(class_name_c)									\
 class_name_c::class_name_c(									\
-                           int fl, int fc, const char *ffile,					\
-                           int ll, int lc, const char *lfile)					\
-			  :symbol_c(fl, fc, ffile, ll, lc, lfile) {}				\
+                           int fl, int fc, const char *ffile, long int forder,			\
+                           int ll, int lc, const char *lfile, long int lorder)			\
+			  :symbol_c(fl, fc, ffile, forder, ll, lc, lfile, lorder) {}		\
 void *class_name_c::accept(visitor_c &visitor) {return visitor.visit(this);}
 
 
 #define SYM_REF1(class_name_c, ref1)								\
 class_name_c::class_name_c(symbol_c *ref1,							\
-                           int fl, int fc, const char *ffile,					\
-                           int ll, int lc, const char *lfile)					\
-			  :symbol_c(fl, fc, ffile, ll, lc, lfile) {				\
+                           int fl, int fc, const char *ffile, long int forder,			\
+                           int ll, int lc, const char *lfile, long int lorder)			\
+			  :symbol_c(fl, fc, ffile, forder, ll, lc, lfile, lorder) {		\
   this->ref1 = ref1;										\
 }												\
 void *class_name_c::accept(visitor_c &visitor) {return visitor.visit(this);}
@@ -165,9 +167,9 @@
 #define SYM_REF2(class_name_c, ref1, ref2)							\
 class_name_c::class_name_c(symbol_c *ref1,							\
 			   symbol_c *ref2,							\
-                           int fl, int fc, const char *ffile,					\
-                           int ll, int lc, const char *lfile)					\
-			  :symbol_c(fl, fc, ffile, ll, lc, lfile) {				\
+                           int fl, int fc, const char *ffile, long int forder,			\
+                           int ll, int lc, const char *lfile, long int lorder)			\
+			  :symbol_c(fl, fc, ffile, forder, ll, lc, lfile, lorder) {		\
   this->ref1 = ref1;										\
   this->ref2 = ref2;										\
 }												\
@@ -178,9 +180,9 @@
 class_name_c::class_name_c(symbol_c *ref1,							\
 			   symbol_c *ref2,							\
 			   symbol_c *ref3,							\
-                           int fl, int fc, const char *ffile,					\
-                           int ll, int lc, const char *lfile)					\
-			  :symbol_c(fl, fc, ffile, ll, lc, lfile) {				\
+                           int fl, int fc, const char *ffile, long int forder,			\
+                           int ll, int lc, const char *lfile, long int lorder)			\
+			  :symbol_c(fl, fc, ffile, forder, ll, lc, lfile, lorder) {		\
   this->ref1 = ref1;										\
   this->ref2 = ref2;										\
   this->ref3 = ref3;										\
@@ -193,9 +195,9 @@
 			   symbol_c *ref2,							\
 			   symbol_c *ref3,							\
 			   symbol_c *ref4,							\
-                           int fl, int fc, const char *ffile,					\
-                           int ll, int lc, const char *lfile)					\
-			  :symbol_c(fl, fc, ffile, ll, lc, lfile) {				\
+                           int fl, int fc, const char *ffile, long int forder,			\
+                           int ll, int lc, const char *lfile, long int lorder)			\
+			  :symbol_c(fl, fc, ffile, forder, ll, lc, lfile, lorder) {		\
   this->ref1 = ref1;										\
   this->ref2 = ref2;										\
   this->ref3 = ref3;										\
@@ -210,9 +212,9 @@
 			   symbol_c *ref3,							\
 			   symbol_c *ref4,							\
 			   symbol_c *ref5,							\
-                           int fl, int fc, const char *ffile,					\
-                           int ll, int lc, const char *lfile)					\
-			  :symbol_c(fl, fc, ffile, ll, lc, lfile) {				\
+                           int fl, int fc, const char *ffile, long int forder,			\
+                           int ll, int lc, const char *lfile, long int lorder)			\
+			  :symbol_c(fl, fc, ffile, forder, ll, lc, lfile, lorder) {		\
   this->ref1 = ref1;										\
   this->ref2 = ref2;										\
   this->ref3 = ref3;										\
@@ -230,9 +232,9 @@
 			   symbol_c *ref4,							\
 			   symbol_c *ref5,							\
 			   symbol_c *ref6,							\
-                           int fl, int fc, const char *ffile,					\
-                           int ll, int lc, const char *lfile)					\
-			  :symbol_c(fl, fc, ffile, ll, lc, lfile) {				\
+                           int fl, int fc, const char *ffile, long int forder,			\
+                           int ll, int lc, const char *lfile, long int lorder)			\
+			  :symbol_c(fl, fc, ffile, forder, ll, lc, lfile, lorder) {		\
   this->ref1 = ref1;										\
   this->ref2 = ref2;										\
   this->ref3 = ref3;										\

--- a/absyntax/absyntax.hh	Thu Apr 14 17:35:25 2011 +0100
+++ b/absyntax/absyntax.hh	Thu Apr 14 18:12:59 2011 +0100
@@ -71,14 +71,16 @@
     int first_line;
     int first_column;
     const char *first_file;  /* filename referenced by first line/column */
+    long int first_order;    /* relative order in which it is read by lexcial analyser */
     int last_line;
     int last_column;
     const char *last_file;  /* filename referenced by last line/column */
+    long int last_order;    /* relative order in which it is read by lexcial analyser */
 
   public:
     /* default constructor */
-    symbol_c(int fl = 0, int fc = 0, const char *ffile = NULL /* filename */,
-             int ll = 0, int lc = 0, const char *lfile = NULL /* filename */
+    symbol_c(int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0, /* order in which it is read by lexcial analyser */
+             int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0  /* order in which it is read by lexcial analyser */
             );
 
     /* default destructor */
@@ -96,8 +98,8 @@
 
   public:
     token_c(const char *value, 
-            int fl = 0, int fc = 0, const char *ffile = NULL /* filename */,
-            int ll = 0, int lc = 0, const char *lfile = NULL /* filename */
+            int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0, /* order in which it is read by lexcial analyser */
+            int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0  /* order in which it is read by lexcial analyser */
            );
 };
 
@@ -109,13 +111,13 @@
     symbol_c **elements;
 
   public:
-    list_c(int fl = 0, int fc = 0, const char *ffile = NULL /* filename */,
-           int ll = 0, int lc = 0, const char *lfile = NULL /* filename */
+    list_c(int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0, /* order in which it is read by lexcial analyser */
+           int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0  /* order in which it is read by lexcial analyser */
           );
 
     list_c(symbol_c *elem, 
-	   int fl = 0, int fc = 0, const char *ffile = NULL /* filename */,
-           int ll = 0, int lc = 0, const char *lfile = NULL /* filename */
+           int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0, /* order in which it is read by lexcial analyser */
+           int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0  /* order in which it is read by lexcial analyser */
           );
      /* insert a new element */
     virtual void add_element(symbol_c *elem);
@@ -128,11 +130,11 @@
 class class_name_c:	public list_c {											\
   public:														\
     class_name_c(													\
-                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, 					\
-                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */);					\
+                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0,			\
+                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0);			\
     class_name_c(symbol_c *elem, 											\
-                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, 					\
-                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */);					\
+                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0,			\
+                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0);			\
     virtual void *accept(visitor_c &visitor);										\
 };
 
@@ -141,8 +143,8 @@
 class class_name_c: 	public token_c {										\
   public:														\
     class_name_c(const char *value, 											\
-                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, 					\
-                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */);					\
+                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0,			\
+                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0);			\
     virtual void *accept(visitor_c &visitor);										\
 };
 
@@ -151,8 +153,8 @@
 class class_name_c: public symbol_c {											\
   public:														\
     class_name_c(		 											\
-                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, 					\
-                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */);					\
+                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0,			\
+                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0);			\
     virtual void *accept(visitor_c &visitor);										\
 };
 
@@ -163,8 +165,8 @@
     symbol_c *ref1;													\
   public:														\
     class_name_c(symbol_c *ref1,											\
-                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, 					\
-                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */);					\
+                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0,			\
+                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0);			\
     virtual void *accept(visitor_c &visitor);										\
 };
 
@@ -177,8 +179,8 @@
   public:														\
     class_name_c(symbol_c *ref1,											\
 		 symbol_c *ref2 = NULL,											\
-                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, 					\
-                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */);					\
+                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0,			\
+                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0);			\
     virtual void *accept(visitor_c &visitor);										\
 };
 
@@ -193,8 +195,8 @@
     class_name_c(symbol_c *ref1,											\
 		 symbol_c *ref2,											\
 		 symbol_c *ref3,											\
-                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, 					\
-                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */);					\
+                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0,			\
+                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0);			\
     virtual void *accept(visitor_c &visitor);										\
 };
 
@@ -211,8 +213,8 @@
 		 symbol_c *ref2,											\
 		 symbol_c *ref3,											\
 		 symbol_c *ref4 = NULL,											\
-                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, 					\
-                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */);					\
+                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0,			\
+                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0);			\
     virtual void *accept(visitor_c &visitor);										\
 };
 
@@ -231,8 +233,8 @@
 		 symbol_c *ref3,											\
 		 symbol_c *ref4,											\
 		 symbol_c *ref5,											\
-                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, 					\
-                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */);					\
+                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0,			\
+                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0);			\
     virtual void *accept(visitor_c &visitor);										\
 };
 
@@ -253,8 +255,8 @@
 		 symbol_c *ref4,											\
 		 symbol_c *ref5,											\
 		 symbol_c *ref6 = NULL,											\
-                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, 					\
-                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */);					\
+                 int fl = 0, int fc = 0, const char *ffile = NULL /* filename */, long int forder=0,			\
+                 int ll = 0, int lc = 0, const char *lfile = NULL /* filename */, long int lorder=0);			\
     virtual void *accept(visitor_c &visitor);										\
 };
 

--- a/stage1_2/iec.flex	Thu Apr 14 17:35:25 2011 +0100
+++ b/stage1_2/iec.flex	Thu Apr 14 18:12:59 2011 +0100
@@ -179,18 +179,33 @@
       result = YY_NULL;\
     }
 
+
+/* A counter to track the order by which each token is processed.
+ * NOTE: This counter is not exactly linear (i.e., it does not get incremented by 1 for each token).
+ *       i.e.. it may get incremented by more than one between two consecutive tokens.
+ *       This is due to the fact that the counter gets incremented every 'user action' in flex,
+ *       however not every user action will result in a token being passed to bison.
+ *       Nevertheless this is still OK, as we are only interested in the relative
+ *       ordering of tokens...
+ */
+static long int current_order = 0;
+
+
 /* Macro that is executed for every action.
  * We use it to pass the location of the token
  * back to the bison parser...
  */
 #define YY_USER_ACTION {\
-	yylloc.first_line = current_tracking->lineNumber;\
-	yylloc.first_column = current_tracking->currentTokenStart;\
-	yylloc.first_file = current_filename;\
-	yylloc.last_line = current_tracking->lineNumber;\
-	yylloc.last_column = current_tracking->currentChar - 1;\
-	yylloc.last_file = current_filename;\
-	current_tracking->currentTokenStart = current_tracking->currentChar;\
+	yylloc.first_line = current_tracking->lineNumber;			\
+	yylloc.first_column = current_tracking->currentTokenStart;		\
+	yylloc.first_file = current_filename;					\
+	yylloc.first_order = current_order;					\
+	yylloc.last_line = current_tracking->lineNumber;			\
+	yylloc.last_column = current_tracking->currentChar - 1;			\
+	yylloc.last_file = current_filename;					\
+	yylloc.last_order = current_order;					\
+	current_tracking->currentTokenStart = current_tracking->currentChar;	\
+	current_order++;							\
 	}
 
 

--- a/stage1_2/iec.y	Thu Apr 14 17:35:25 2011 +0100
+++ b/stage1_2/iec.y	Thu Apr 14 18:12:59 2011 +0100
@@ -116,9 +116,9 @@
 /* Macros used to pass the line and column locations when
  * creating a new object for the abstract syntax tree.
  */
-#define locloc(foo) foo.first_line, foo.first_column, foo.first_file, foo.last_line, foo.last_column, foo.last_file
-#define   locf(foo) foo.first_line, foo.first_column, foo.first_file
-#define   locl(foo) foo.last_line,  foo.last_column, foo.last_file
+#define locloc(foo) foo.first_line, foo.first_column, foo.first_file, foo.first_order, foo.last_line, foo.last_column, foo.last_file, foo.last_order
+#define   locf(foo) foo.first_line, foo.first_column, foo.first_file, foo.first_order
+#define   locl(foo) foo.last_line,  foo.last_column,  foo.last_file,  foo.last_order
 
 /* Redefine the default action to take for each rule, so that the filenames are correctly processed... */
 # define YYLLOC_DEFAULT(Current, Rhs, N)                                \
@@ -128,9 +128,11 @@
                (Current).first_line   = YYRHSLOC(Rhs, 1).first_line;         \
                (Current).first_column = YYRHSLOC(Rhs, 1).first_column;       \
                (Current).first_file   = YYRHSLOC(Rhs, 1).first_file;         \
+               (Current).first_order  = YYRHSLOC(Rhs, 1).first_order;        \
                (Current).last_line    = YYRHSLOC(Rhs, N).last_line;          \
                (Current).last_column  = YYRHSLOC(Rhs, N).last_column;        \
                (Current).last_file    = YYRHSLOC(Rhs, 1).last_file;          \
+               (Current).last_order   = YYRHSLOC(Rhs, 1).last_order;         \
              }                                                               \
            else                                                              \
              {                                                               \
@@ -140,6 +142,8 @@
                  YYRHSLOC(Rhs, 0).last_column;                               \
                (Current).first_file   = (Current).last_file   =              \
                  YYRHSLOC(Rhs, 0).last_file;                                 \
+               (Current).first_order  = (Current).last_order  =              \
+                 YYRHSLOC(Rhs, 0).last_order;                                \
              }                                                               \
          while (0)
 
@@ -205,9 +209,11 @@
 void print_err_msg(int first_line,
                    int first_column,
                    const char *first_filename,
+                   long int first_order,
                    int last_line,
                    int last_column,
                    const char *last_filename,
+                   long int last_order,
                    const char *additional_error_msg);
 %}
 
@@ -245,12 +251,14 @@
  */
 #if ! defined YYLTYPE && ! defined YYLTYPE_IS_DECLARED
   typedef struct {
-    int first_line;
-    int first_column;
+    int         first_line;
+    int         first_column;
     const char *first_file;
-    int last_line;
-    int last_column;
+    long int    first_order;
+    int         last_line;
+    int         last_column;
     const char *last_file;
+    long int    last_order;
   } yyltype__local;
   #define YYLTYPE yyltype__local
 #endif
@@ -7892,9 +7900,11 @@
 void print_err_msg(int first_line,
                    int first_column,
                    const char *first_filename,
+                   long int first_order,
                    int last_line,
                    int last_column,
                    const char *last_filename,
+                   long int last_order,
                    const char *additional_error_msg) {
 
   const char *unknown_file = "<unknown_file>";
@@ -8000,9 +8010,11 @@
                          il_operator->first_line,
                          il_operator->first_column,
                          il_operator->first_file,
+                         il_operator->first_order,
                          il_operator->last_line,
                          il_operator->last_column,
-                         il_operator->last_file
+                         il_operator->last_file,
+                         il_operator->last_order
                         );
   free(il_operator);
   return res;

--- a/stage3/visit_expression_type.cc	Thu Apr 14 17:35:25 2011 +0100
+++ b/stage3/visit_expression_type.cc	Thu Apr 14 18:12:59 2011 +0100
@@ -43,25 +43,8 @@
 #include <string.h>
 #include <strings.h>
 
+
 /*
-static inline symbol_c * FIRST_(symbol_c *symbol1, symbol_c *symbol2) {
-  if (symbol1->first_file  == symbol2->first_file)   return symbol1;
-
-  if (symbol1->first_line   < symbol2->first_line)   return symbol1;
-  if (symbol1->first_line   > symbol2->first_line)   return symbol2;
-  if (symbol1->first_column < symbol2->first_column) return symbol1;
-  if (symbol1->first_column > symbol2->first_column) return symbol2;
-  return symbol1;
-}
-
-#define FIRST_(symbol1, symbol2) (((symbol1)->last_file   == (symbol2)->first_file)   ? (symbol1) :    \
-                                  ((symbol1)->first_file  == (symbol2)->last_file)    ? (symbol2) :    \
-                                  ((symbol1)->first_line   < (symbol2)->first_line)   ? (symbol1) :    \
-                                  ((symbol1)->first_line   > (symbol2)->first_line)   ? (symbol2) :    \
-                                  ((symbol1)->first_column < (symbol2)->first_column) ? (symbol1) :    \
-                                  ((symbol1)->first_column > (symbol2)->first_column) ? (symbol2) :    \
-                                  (symbol1))
-*/
 #define FIRST_(symbol1, symbol2) (((symbol1)->first_line   < (symbol2)->first_line)   ? (symbol1) :    \
                                   ((symbol1)->first_line   > (symbol2)->first_line)   ? (symbol2) :    \
                                   ((symbol1)->first_column < (symbol2)->first_column) ? (symbol1) :    \
@@ -73,6 +56,9 @@
                                   ((symbol1)->last_column  < (symbol2)->last_column)  ? (symbol2) :    \
                                   ((symbol1)->last_column  > (symbol2)->last_column)  ? (symbol1) :    \
                                   (symbol1))
+*/
+#define FIRST_(symbol1, symbol2) (((symbol1)->first_order < (symbol2)->first_order)   ? (symbol1) : (symbol2))
+#define  LAST_(symbol1, symbol2) (((symbol1)->last_order  > (symbol2)->last_order)    ? (symbol1) : (symbol2))
 
 #define STAGE3_ERROR(symbol1, symbol2, msg) {                                          \
     fprintf(stderr, "%s:(%d:%d) .. %s(%d:%d): %s\n",                                   \