Allow 'pri' to prioritize multiple todos at once.

Fixes issue #5

topydo/lib/PriorityCommand.py

@@ -30,14 +30,19 @@ class PriorityCommand(Command):
         if not super(PriorityCommand, self).execute():
             return False
 
-        number = None
+        numbers = None
         priority = None
         try:
-            number = self.argument(0)
-            priority = self.argument(1)
-            todo = self.todolist.todo(number)
+            numbers = self.args[:-1]
+            priority = self.args[-1]
+
+            if len(numbers) > 0:
+                todos = []
+                for number in numbers:
+                    todos.append(self.todolist.todo(number))
 
                 if is_valid_priority(priority):
+                    for todo in todos:
                         old_priority = todo.priority()
                         self.todolist.set_priority(todo, priority)
 
@@ -50,10 +55,14 @@ class PriorityCommand(Command):
                         self.out(self.printer.print_todo(todo))
                 else:
                     self.error("Invalid priority given.")
+            else:
+                self.error(self.usage())
+        except IndexError:
+            self.error(self.usage())
         except InvalidCommandArgument:
             self.error(self.usage())
         except (InvalidTodoException):
-            if number and priority:
+            if len(numbers) > 0 and priority:
                 self.error( "Invalid todo number given.")
             else:
                 self.error(self.usage())