- Added more fine-grained control for the associativity of tupling:

--tupling=n	* 0: right-associative; 1: left-associative; others are
  reserved for future use.
  --ra-tupling	* Sets the default, but is there for symmetry.

src/switches.c

@@ -39,7 +39,7 @@ switchesInit (int argc, char **argv)
   switches.engine = POR_ENGINE;	// default is partial ordering engine
   switches.match = 0;		// default matching
   switches.clp = 0;
-  switches.la_tupling = false;
+  switches.tupling = 0;
 
   // Pruning and Bounding
   switches.prune = 2;		// default pruning method
@@ -379,21 +379,52 @@ switcher (const int process, int index)
 	}
     }
 
+  if (detect (' ', "ra-tupling", 0))
+    {
+      if (!process)
+	{
+	  /* for experts only
+	     helptext ("--ra-tupling", "compile using right-associative tupling");
+	   */
+	}
+      else
+	{
+	  switches.tupling = 0;
+	  return index;
+	}
+    }
+
   if (detect (' ', "la-tupling", 0))
     {
       if (!process)
 	{
-	  /* not very important
+	  /* for experts only
 	     helptext ("--la-tupling", "compile using left-associative tupling");
 	   */
 	}
       else
 	{
-	  switches.la_tupling = true;
+	  switches.tupling = 1;
 	  return index;
 	}
     }
 
+  if (detect (' ', "tupling", 1))
+    {
+      if (!process)
+	{
+	  /* for experts only
+	     helptext ("--tupling", "tupling type to use");
+	   */
+	}
+      else
+	{
+	  switches.tupling = integer_argument ();
+	  return index;
+	}
+    }
+
+
   /* ==================
    *  Modelchecker only
    */

src/switches.h

@@ -18,7 +18,7 @@ struct switchdata
   int engine;			//!< Engine type (POR_ENGINE,ARACHNE_ENGINE)
   int match;			//!< Matching type.
   int clp;			//!< Do we use clp?
-  int la_tupling;		//!< Tupling is by default right-associative, optionally left-associative.
+  int tupling;			//!< Tupling is by default 0: right-associative, optionally 1: left-associative.
 
   // Pruning and Bounding
   int prune;			//!< Type of pruning.

src/tac.c

@@ -167,17 +167,19 @@ tacTuple (Tac taclist)
     }
   else
     {
-      if (switches.la_tupling)
+      switch (switches.tupling)
-	{
-	  /* switch --la-tupling */
-	  /* left-associative */
-	  return tacTupleLa (taclist);
-	}
-      else
 	{
+	case 0:
+	  /* case 0: as well as */
 	  /* DEFAULT behaviour */
 	  /* right-associative */
 	  return tacTupleRa (taclist);
+	case 1:
+	  /* switch --la-tupling */
+	  /* left-associative */
+	  return tacTupleLa (taclist);
+	default:
+	  error ("Unknown tupling mode (--tupling=%i)", switches.tupling);
 	}
     }
 }