"To run without saving" was the first idea I got, but it was difficult to pursue in first phase. After your hints I think I have achieved what you have described.

I have done a few fixes(luckily in a single file ScriptBinding.py) which are giving satisfactory result.

I am attaching the original, modified and the diff version of files named ScriptBindingOriginal.py, ScriptBinding.py and ScriptBinding.diff respectively. 

Here is what I am getting with the new code
Traceback (most recent call last):
  File "*Untitled*", line 3, in <module>
  File "*Untitled*", line 2, in f
ZeroDivisionError: division by zero

This is the summary of the patch (idle-python3.4)

+import io
....

#====== One member in class for reducing annoyance ====
        self.no_save = False

#====== New definition for function tabnanny======
-    def tabnanny(self, filename):
+    def tabnanny(self, source):
+        f = io.StringIO(source)# , os.linesep  *****Maybe*****
-        with tokenize.open(filename) as f:

#====== Added 2 functions =========
    def source_from_file(self, filename):
        with open(filename, 'rb') as f:
            source = f.read()
        if b'\r' in source:
            source = source.replace(b'\r\n', b'\n')
            source = source.replace(b'\r', b'\n')
        if source and source[-1] != ord(b'\n'):
            source = source + b'\n'
        return source
    
    def source_from_editor(self):
        self.editwin.io.fixlastline()
        source = self.editwin.text.get("1.0", "end-1c")
        return source

#====== New definition for function checksyntax======
-    def checksyntax(self, filename):
+    def checksyntax(self, source, filename):

#====== Changes in function run_module_event (Main) ==========
    def _run_module_event(self, event):
        filename = self.getfilename()
        filename = self.getfilename()
        if not filename:
            self.no_save = True
            source = self.source_from_editor()
            filename = self.editwin.top.wm_title()
        else:
            source = self.source_from_file(filename)
            self.no_save = False
        code = self.checksyntax(source, filename)
        if not code:
            return 'break'
        if not self.tabnanny(source):
            return 'break'
        interp = self.shell.interp
        if PyShell.use_subprocess:
            interp.restart_subprocess(with_cwd=False)
        if not self.no_save:
           ....
        interp.runcode(code)
        return 'break'

#====== Finally suppressing the annoyance ======
            if autosave and filename:
                self.editwin.io.save(None)
            elif self.no_save:
                filename = None
            else:
                confirm = self.ask_save_dialog()

Please have a review and let me know if it can solve this issue.