# HG changeset patch
# User Mario de Sousa <msousa@fe.up.pt>
# Date 1343734744 -3600
# Node ID 0c7663fdc8d319ff12408c699280dbdfbd1a1158
# Parent  509b79602f7c30a37935d311a581f3269a39bce3
Aloow use of SFC STEPs as variables.

diff -r 509b79602f7c -r 0c7663fdc8d3 absyntax_utils/search_varfb_instance_type.cc
--- a/absyntax_utils/search_varfb_instance_type.cc	Sat Jul 28 09:07:55 2012 +0100
+++ b/absyntax_utils/search_varfb_instance_type.cc	Tue Jul 31 12:39:04 2012 +0100
@@ -142,8 +142,12 @@
   /* What if the variable has not been declared?  Then this should not be a compiler error! 
    * However, currently stage 2 of the compiler already detects when variables have not been delcared,
    * so if the variable's declaration is not found, then that means that we have an internal compiler error!
+   * 
+   * Actually, the above is not true anymore. See the use of the any_symbolic_variable in iec_bison.yy
+   *  - when defining the delay of a delayed action association in SFC
+   *  - in program connections inside configurations (will this search_varfb_instance_type_c class be called to handle this??)
    */
-  if (NULL == current_type_id) ERROR; 
+  // if (NULL == current_type_id) ERROR; 
 
   return NULL;
 }
diff -r 509b79602f7c -r 0c7663fdc8d3 stage1_2/iec_bison.yy
--- a/stage1_2/iec_bison.yy	Sat Jul 28 09:07:55 2012 +0100
+++ b/stage1_2/iec_bison.yy	Tue Jul 31 12:39:04 2012 +0100
@@ -5139,7 +5139,9 @@
 initial_step:
   INITIAL_STEP step_name ':' action_association_list END_STEP
 //  INITIAL_STEP identifier ':' action_association_list END_STEP
-	{$$ = new initial_step_c($2, $4, locloc(@$));}
+	{$$ = new initial_step_c($2, $4, locloc(@$));
+	 variable_name_symtable.insert($2, prev_declared_variable_name_token); // A step name may later be used as a structured variable!!
+	}
 /* ERROR_CHECK_BEGIN */
 | INITIAL_STEP ':' action_association_list END_STEP
   {$$ = NULL; print_err_msg(locf(@1), locl(@2), "no step name defined in initial step declaration."); yynerrs++;}
@@ -5159,7 +5161,9 @@
 step:
   STEP step_name ':' action_association_list END_STEP
 //  STEP identifier ':' action_association_list END_STEP
-	{$$ = new step_c($2, $4, locloc(@$));}
+	{$$ = new step_c($2, $4, locloc(@$));
+	 variable_name_symtable.insert($2, prev_declared_variable_name_token); // A step name may later be used as a structured variable!!
+	}
 /* ERROR_CHECK_BEGIN */
 | STEP ':' action_association_list END_STEP
   {$$ = NULL; print_err_msg(locl(@1), locf(@2), "no step name defined in step declaration."); yynerrs++;}
@@ -5261,9 +5265,58 @@
 | SL		{$$ = new timed_qualifier_c(strdup("SL"), locloc(@$));}
 ;
 
+/* NOTE: A step_name may be used as a structured vaqriable, in order to access the status bit (e.g. Step1.X) 
+ *       or the time it has been active (e.g. Step1.T). 
+ *       In order to allow the step name to be used as a variable inside ST expressions (only ST expressions ??)
+ *       when defining transitions, we need to add the step_name to the list of previously declared variables.
+ *       This allows the step name to be used as a variable inside all transition expressions, as the user
+ *       can clearly define the transition _after_ the step itself has been defined/declared, so the 
+ *       'variable' is previously 'declared'.
+ *
+ *       However, when defining/declaring a step, a variable name can also be used to define a timed
+ *       action association. In this case, we may have a circular reference:
+ *        e.g.
+ *            ...
+ *             STEP step1:
+ *                action1 (D,t#100ms);
+ *             end_step
+ *
+ *             STEP step2:
+ *                action1 (D,step3.T);  <---- forward reference to step3.T !!!!!!
+ *             end_step
+ *
+ *             STEP step3:
+ *                action1 (D,step2.T);  <---- back reference to step2.T
+ *             end_step
+ *
+ *
+ *         There is no way the user can always use the step3.T variable only after it has
+ *         been 'declared'. So adding the steps to the list of previously declared variables 
+ *         when the steps are declared is not a solution to the above situation.
+ *
+ *         Fortunately, the standard does not allow ST expressions in the above syntax
+ *         (i.e. when defining the delay of a timed actions), but only either a 
+ *         Time literal, or a variable.
+ *         This is why we change the definition of action_time from
+ *         action_time:
+ *           duration
+ *         | variable
+ *         ;
+ *
+ *         to:
+ *         action_time:
+ *           duration
+ *         | any_symbolic_variable
+ *         ;
+ *
+ *       NOTE that this same problem does not occur with the 'indicator_name': it does not
+ *       make sense to set/indicate a step1.X variable, as these variables are read-only!
+ */     
+    
 action_time:
   duration
-| variable
+//| variable
+  | any_symbolic_variable
 ;
 
 indicator_name: variable;
diff -r 509b79602f7c -r 0c7663fdc8d3 stage1_2/iec_flex.ll
--- a/stage1_2/iec_flex.ll	Sat Jul 28 09:07:55 2012 +0100
+++ b/stage1_2/iec_flex.ll	Tue Jul 31 12:39:04 2012 +0100
@@ -1616,8 +1616,8 @@
 {fixed_point}ms		{yylval.ID=strdup(yytext); yylval.ID[yyleng-2] = '\0'; return fixed_point_ms_token;}
 
 _			/* do nothing - eat it up!*/
-\#			{/*fprintf(stderr, "poping from time_literal_state (###)\n");*/ yy_pop_state(); return end_interval_token;}
-.			{ERROR;}
+\#			{/*fprintf(stderr, "popping from time_literal_state (###)\n");*/ yy_pop_state(); return end_interval_token;}
+.			{/*fprintf(stderr, "time_literal_state: found invalid character '%s'. Aborting!\n", yytext);*/ ERROR;}
 \n			{ERROR;}
 }
 	/*******************************/