--- a/stage1_2/iec.flex	Sun Oct 28 20:15:54 2007 +0100
+++ b/stage1_2/iec.flex	Sun Oct 28 22:03:27 2007 +0100
@@ -753,8 +753,17 @@
 
 <<EOF>>			{
 			  if (--include_stack_ptr < 0) {
+			      /* yyterminate() terminates the scanner and returns a 0 to the 
+			       * scanner's  caller, indicating "all done".
+			       *	
+			       * Our syntax parser (written with bison) has the token	
+			       * END_OF_INPUT associated to the value 0, so even though
+			       * we don't explicitly return the token END_OF_INPUT
+			       * calling yyterminate() is equivalent to doing that. 
+			       */ 	
 			    yyterminate();
-			  } else {
+			  }      
+ else {
 			    yy_delete_buffer(YY_CURRENT_BUFFER);
 			    yy_switch_to_buffer((include_stack[include_stack_ptr]).buffer_state);
 			    yylineno = include_stack[include_stack_ptr].lineno;
@@ -1203,6 +1212,7 @@
 	 *       ANDN and &N)!
 	 */
  /* The following tokens clash with ST expression operators and Standard Functions */
+ /* They are also keywords! */
 AND		return AND;
 MOD		return MOD;
 OR		return OR;
@@ -1210,6 +1220,7 @@
 NOT		return NOT;
 
  /* The following tokens clash with Standard Functions */
+<il_state>{
 ADD		return ADD;
 DIV		return DIV;
 EQ		return EQ;
@@ -1220,15 +1231,19 @@
 MUL		return MUL;
 NE		return NE;
 SUB		return SUB;
+}
 
  /* The following tokens clash with SFC action qualifiers */
+<il_state>{
 S		return S;
 R		return R;
+}
 
  /* The following tokens clash with ST expression operators */
 &		return AND2;
 
  /* The following tokens have no clashes */
+<il_state>{
 LD		return LD;
 LDN		return LDN;
 ST		return ST;
@@ -1254,7 +1269,7 @@
 JMP		return JMP;
 JMPC		return JMPC;
 JMPCN		return JMPCN;
-
+}
 
 	/***********************/
 	/* B 3.1 - Expressions */

--- a/stage1_2/iec.y	Sun Oct 28 20:15:54 2007 +0100
+++ b/stage1_2/iec.y	Sun Oct 28 22:03:27 2007 +0100
@@ -206,6 +206,15 @@
 /*****************************/
 /* Prelimenary constructs... */
 /*****************************/
+/* A token used to identify the very end of the input file
+ * after all includes have already been processed.
+ *
+ * Flex automatically returns the token with value 0
+ * at the end of the file. We therefore specify
+ * a token with that exact same value here.
+ */
+%token END_OF_INPUT 0
+
 /* A bogus token that, in principle, flex MUST NEVER generate */
 /* USE 1:
  * ======
@@ -1384,7 +1393,7 @@
 	}
 | library library_element_declaration
 	{$$ = $1; $$->add_element($2);}
-| library error
+| library error END_OF_INPUT
 	{$$ = NULL;
 	 print_err_msg(current_filename, @2.first_line, "unknown error.");
 	 yyerrok;
@@ -1517,10 +1526,14 @@
  * this list MUST be kept consistent!!
  */
 /**/
+/*
 | PRIORITY		{$$ = new identifier_c(strdup("PRIORITY"), locloc(@$));}
 | SINGLE		{$$ = new identifier_c(strdup("SINGLE"), locloc(@$));}
 | INTERVAL		{$$ = new identifier_c(strdup("INTERVAL"), locloc(@$));}
+*/
 /**/
+/* NOTE: AND, NOT, MOD, OR and XOR are keywords, so should not appear on this list... */
+/*
 | LD_operator		{$$ = il_operator_c_2_identifier_c($1);}
 | LDN_operator		{$$ = il_operator_c_2_identifier_c($1);}
 | ST_operator		{$$ = il_operator_c_2_identifier_c($1);}
@@ -1536,11 +1549,12 @@
 | IN_operator		{$$ = il_operator_c_2_identifier_c($1);}
 | PT_operator		{$$ = il_operator_c_2_identifier_c($1);}
 | ANDN_operator		{$$ = il_operator_c_2_identifier_c($1);}
+*/
 /* NOTE: ANDN2_operator corresponds to the string '&N' in the source code!
  *       This is __not__ a valid name, so it is omitted from this list!!
  *| ANDN2_operator		{$$ = il_operator_c_2_identifier_c($1);}
  */
-/* NOTE: 'AND' is a keyword, so should not appear on this list... */
+/*
 | ORN_operator		{$$ = il_operator_c_2_identifier_c($1);}
 | XORN_operator		{$$ = il_operator_c_2_identifier_c($1);}
 | ADD_operator		{$$ = il_operator_c_2_identifier_c($1);}
@@ -1562,6 +1576,7 @@
 | JMP_operator		{$$ = il_operator_c_2_identifier_c($1);}
 | JMPC_operator		{$$ = il_operator_c_2_identifier_c($1);}
 | JMPCN_operator	{$$ = il_operator_c_2_identifier_c($1);}
+*/
 ;
 
 /*********************/
@@ -5369,7 +5384,7 @@
 const char *standard_function_block_names[] = {
 // 2.5.2.3.1  Bistable elements
 //   Table 34 - Standard bistable function blocks
-//"SR","RS",
+"SR","RS",
 // 2.5.2.3.2  Edge detection
 //   Table 35 - Standard edge detection function blocks
 "R_TRIG","F_TRIG",