example howto handle Exceptions in shell

FlatCAMApp.py

@@ -644,14 +644,32 @@ class App(QtCore.QObject):
         else:
             self.defaults['stats'][resource] = 1
 
+    class TclErrorException(Exception):
+        """
+        this exception is deffined here, to be able catch it if we sucessfully handle all errors from shell command
+        """
+
+        pass
+
+    def raiseTclUnknownError(self, unknownException):
+        """
+        raise Exception if is different type  than TclErrorException
+        :param unknownException:
+        :return:
+        """
+
+        if not isinstance(unknownException, self.TclErrorException):
+            self.raiseTclError("Unknown error: %s" % str(unknownException))
+
     def raiseTclError(self, text):
         """
         this method  pass exception from python into TCL as error, so we get stacktrace and reason
         :param text: text of error
         :return: raise exception
         """
+
         self.tcl.eval('return -code error "%s"' % text)
-        raise Exception(text)
+        raise self.TclErrorException(text)
 
     def exec_command(self, text):
         """
@@ -660,6 +678,7 @@ class App(QtCore.QObject):
         :param text: Input command
         :return: None
         """
+
         self.report_usage('exec_command')
 
         text = str(text)
@@ -2659,6 +2678,8 @@ class App(QtCore.QObject):
             :param args: array of arguments
             :return: "Ok" if completed without errors
             '''
+
+            try:
                 a, kwa = h(*args)
                 types = {'outname': str}
 
@@ -2698,6 +2719,9 @@ class App(QtCore.QObject):
                 except Exception as e:
                     self.raiseTclError("Failed: %s" % str(e))
 
+            except Exception as unknown:
+                self.raiseTclUnknownError(unknown)
+
             return 'Ok'
 
         def isolate(name=None, *args):