better exception handling

fossils.py

@@ -63,8 +63,10 @@ class Window(QWidget, Ui_Form):
 def run_simulation(testname):
     """Runs a python file
     """
-
-    exec(open(testname, encoding='utf-8').read(), 
+    # thanks to the "compile" command, the filename appears in the stack
+    # trace in case of errors
+    script = open(testname, encoding='utf-8').read()   
+    exec(compile(script, testname, 'exec'), 
         {'__file__': testname, '__name__':'__main__'})    
 
 
@@ -155,13 +157,15 @@ if __name__ == "__main__":
         workspace = win.wrkspLineEdit.text()
         action = win.action
         testname = win.inpFileLineEdit.text()
+        gui = True
     else:
         workspace = None
         action = 'run'
         testname = os.path.abspath(args.file)
+        gui = False
 
     # run the simulation or display results
-    
+
     print(f'action = {action}')
     if action=='run' or action=='post':
         testname = os.path.normcase(testname)  # F:/ => f:/ on Windows
@@ -186,7 +190,14 @@ if __name__ == "__main__":
 
         tee = cxxfem.Tee('stdout.txt')  # split streams
 
-        if action == 'run':
-            run_simulation(testname)
-        elif action == 'post':
-            view_results()
+        try:
+            if action == 'run':
+                run_simulation(testname)
+            elif action == 'post':
+                view_results()
+        except Exception as err:
+            print(f'\n** ERROR: {err}\n')
+            import traceback
+            traceback.print_exc()
+            if gui:
+                input('\nPress <ENTER> to continue...\n')