fixed Inhibitor arcs, misc fixes/improvements

@@ -1637,22 +1637,23 @@ class Inhibitor (Test) :
     def __hash__ (self) :
     def __hash__ (self) :
         return hash(("inhibitor", self._annotation, self._condition))
         return hash(("inhibitor", self._annotation, self._condition))
     def bind (self, binding) :
     def bind (self, binding) :
-        """Return the value of the annotation evaluated through
-        `binding`, or raise `ValueError` of this binding does not
-        validate the condition.
+        """Return no tokens since arc corresponds to an absence of tokens.
+        Raise `ValueError` if this binding does not validate the
+        condition.
 
 
         >>> Inhibitor(Expression('x+1'), Expression('x>0')).bind(Substitution(x=2))
         >>> Inhibitor(Expression('x+1'), Expression('x>0')).bind(Substitution(x=2))
-        Token(3)
+        ()
         >>> try : Inhibitor(Expression('x+1'), Expression('x<0')).bind(Substitution(x=2))
         >>> try : Inhibitor(Expression('x+1'), Expression('x<0')).bind(Substitution(x=2))
         ... except ValueError : print(sys.exc_info()[1])
         ... except ValueError : print(sys.exc_info()[1])
         condition not True for {x -> 2}
         condition not True for {x -> 2}
 
 
         @param binding: a substitution
         @param binding: a substitution
         @type binding: `Substitution`
         @type binding: `Substitution`
-        @return: a value
+        @return: empty tuple
+
         """
         """
         if self._condition(binding) :
         if self._condition(binding) :
-            return self._annotation.bind(binding)
+            return ()
         else :
         else :
             raise ValueError("condition not True for %s" % str(binding))
             raise ValueError("condition not True for %s" % str(binding))
     def modes (self, values) :
     def modes (self, values) :
@@ -2731,6 +2732,9 @@ class Marking (hdict) :
         """
         """
         return cls(((child["id"], child.child("tokens").child().to_obj())
         return cls(((child["id"], child.child("tokens").child().to_obj())
                     for child in tree.get_children("place")))
                     for child in tree.get_children("place")))
+    def __str__ (self) :
+        base = "{%s}" % ", ".join("%s=%s" % pair for pair in sorted(self.items()))
+        return base.replace("={dot}", "")
     def __call__ (self, place) :
     def __call__ (self, place) :
         """Return the marking of `place`. The empty multiset is
         """Return the marking of `place`. The empty multiset is
         returned if `place` is not explicitely given in the marking.
         returned if `place` is not explicitely given in the marking.

@@ -105,7 +105,7 @@ class Graph (Cluster) :
     def dot (self) :
     def dot (self) :
         self.done = set()
         self.done = set()
         return "\n".join(self._dot_text(["digraph {",
         return "\n".join(self._dot_text(["digraph {",
-                                         'charset="UTF-8"',
+#                                         'charset="UTF-8"',
                                          ['node [label="N",'
                                          ['node [label="N",'
                                           ' fillcolor="#FFFFFF",'
                                           ' fillcolor="#FFFFFF",'
                                           ' fontcolor="#000000",'
                                           ' fontcolor="#000000",'
@@ -120,7 +120,9 @@ class Graph (Cluster) :
             return text
             return text
         else :
         else :
             return '"%s"' % text.replace('"', r'\"')
             return '"%s"' % text.replace('"', r'\"')
-    def render (self, filename, engine="dot", debug=False) :
+    def render (self, filename, engine=None, debug=False) :
+        if engine is None :
+            engine = getattr(self, "engine", "dot")
         if engine not in ("dot", "neato", "twopi", "circo", "fdp") :
         if engine not in ("dot", "neato", "twopi", "circo", "fdp") :
             raise ValueError("unknown GraphViz engine %r" % engine)
             raise ValueError("unknown GraphViz engine %r" % engine)
         with codecs.open(filename + ".dot", "w", "utf-8") as outfile :
         with codecs.open(filename + ".dot", "w", "utf-8") as outfile :
@@ -134,12 +136,15 @@ class Graph (Cluster) :
                                     "-o" + filename, outfile.name],
                                     "-o" + filename, outfile.name],
                                    stdin=subprocess.PIPE,
                                    stdin=subprocess.PIPE,
                                    stdout=subprocess.PIPE,
                                    stdout=subprocess.PIPE,
-                                   stderr=subprocess.PIPE)
-        dot.communicate()
+                                   stderr=subprocess.STDOUT)
+        stdout, stderr = dot.communicate()
         if not debug :
         if not debug :
             os.unlink(outfile.name)
             os.unlink(outfile.name)
         if dot.returncode != 0 :
         if dot.returncode != 0 :
-            raise IOError("%s exited with status %s" % (engine, dot.returncode))
+            if stdout.strip() + stderr.strip() :
+                stdout = "\n*** Original error message follows ***\n " + stdout
+            raise IOError("%s exited with status %s%s"
+                          % (engine, dot.returncode, stdout))
     def layout (self, engine="dot", debug=False) :
     def layout (self, engine="dot", debug=False) :
         if engine not in ("dot", "neato", "twopi", "circo", "fdp") :
         if engine not in ("dot", "neato", "twopi", "circo", "fdp") :
             raise ValueError("unknown GraphViz engine %r" % engine)
             raise ValueError("unknown GraphViz engine %r" % engine)
@@ -226,6 +231,7 @@ def extend (module) :
                            for num, node in enumerate(self.node()))
                            for num, node in enumerate(self.node()))
             g = self._copy(nodemap, self.clusters, cluster_attr,
             g = self._copy(nodemap, self.clusters, cluster_attr,
                            place_attr, trans_attr)
                            place_attr, trans_attr)
+            g.engine = engine
             self._copy_edges(nodemap, g, arc_attr)
             self._copy_edges(nodemap, g, arc_attr)
             if graph_attr :
             if graph_attr :
                 graph_attr(self, g.attr)
                 graph_attr(self, g.attr)

@@ -90,8 +90,11 @@ class Builder (object) :
         """raise an exception with appropriate location
         """raise an exception with appropriate location
         """
         """
         if self.stack :
         if self.stack :
-            pos = "[%s:%s]: " % (self.stack[-1].lineno,
-                                 self.stack[-1].col_offset)
+            try :
+                pos = "[%s:%s]: " % (self.stack[-1].lineno,
+                                     self.stack[-1].col_offset)
+            except :
+                pos = ""
         else :
         else :
             pos = ""
             pos = ""
         raise error(pos+message)
         raise error(pos+message)

@@ -297,8 +297,13 @@ def main (args=sys.argv[1:], src=None) :
     if options.check :
     if options.check :
         lineno, trace = Checker(net).run()
         lineno, trace = Checker(net).run()
     if options.simul :
     if options.simul :
+        engine = "dot"
+        for eng in gv_engines :
+            if getattr(options, "gv%s" % eng) :
+                engine = eng
+                break
         try :
         try :
-            simul = Simulator(node, net, draw(net, None), options.port)
+            simul = Simulator(node, net, draw(net, None, engine), options.port)
         except :
         except :
             bug()
             bug()
         simul.start()
         simul.start()