added Window_Interaction_Handler and a simple dialog on startup

Window_Interaction_Handler can be used as a bus system. It is designed to keep track of events until they are being read out somewhere.
The dialog on startup checks whether a config file exists and prompts to create one if it doesn’t.

main.py

@@ -0,0 +1,99 @@
+#!/usr/bin/python3
+import tkinter as tk
+from tkinter import ttk
+import sys, os, json, traceback
+
+def warn(text):
+    print("WARNING: "+str(text), file=sys.stderr)
+    traceback.print_stack()
+
+# easy way to get data out of window events
+class Window_Interaction_Handler:
+    # constructor
+    def __init__(self):
+        self.__window_interactions = {}
+
+    # add a result for an interaction event, saves results in reverse order by default, can optionally call another function
+    def interact(self, name, result, reverse_order=True, additional_action=None, additional_action_parameters=()):
+        if name in self.__window_interactions:
+            if reverse_order:
+                self.__window_interactions[name] = [result] + self.__window_interactions[name]
+            else:
+                self.__window_interactions[name] = self.__window_interactions[name] + [result]
+        else:
+            self.__window_interactions[name] = [result]
+
+        if not additional_action==None:
+            additional_action(*additional_action_parameters)
+
+    # get first result for a given event from the list of results (newest (default) or oldest), removes the returned result from the list by default
+    def get_result(self, name, remove=True):
+        if name in self.__window_interactions and len(self.__window_interactions[name])>0:
+            if remove:
+                result = self.__window_interactions[name].pop(0)
+                if len(self.__window_interactions[name])==0:
+                    del self.__window_interactions[name]
+                return result
+            else:
+                return self.__window_interactions[name][0]
+        else:
+            return None
+
+    # get all results for a given event
+    def get_results(self, name, clear=False):
+        if name in self.__window_interactions and len(self.__window_interactions[name])>0:
+            results = self.__window_interactions[name]
+            if clear:
+                del self.__window_interactions[name]
+            return results
+
+    # clear results for a given event
+    def clear(self, name):
+        if name in self.__window_interactions:
+            del self.__window_interactions[name]
+
+    # destructor
+    def __del__(self):
+        if len(self.__window_interactions)>0:
+            warn("__window_interactions not empty upon destruction of Window_Interaction_Handler:\n"+str(self.__window_interactions))
+
+
+# read configuration
+home_directory = os.path.expanduser("~")
+config_file_path = os.path.join(home_directory, "some_ide_config.json")
+configuration = {}
+if os.path.isfile(config_file_path):
+    try:
+        config_file = open(config_file_path, "r")
+        configuration = json.loads(config_file.read())
+        config_file.close()
+    except:
+        #TODO: show an error message
+        warn("Not implemented!")
+else:
+    # config not found
+    dialog_interaction_handler = Window_Interaction_Handler()
+
+    dialog = tk.Tk()
+    ttk.Label(dialog, text="No configuration found!").pack()
+    buttons_frame = tk.Frame(dialog)
+    buttons_frame.pack()
+    ttk.Button(buttons_frame, text="Create", command=lambda: dialog_interaction_handler.interact("create", True, additional_action=dialog.destroy)).grid(column=0, row=0) #TODO: add functionality
+    ttk.Button(buttons_frame, text="Quit", command=lambda: dialog_interaction_handler.interact("create", False, additional_action=dialog.destroy)).grid(column=1, row=0)  #TODO: add functionality
+    dialog.resizable(0,0)
+    dialog.mainloop()
+
+    if dialog_interaction_handler.get_result("create"):
+        #TODO: store default configuration
+        warn("Not implemented!")
+    else:
+        print("No config present and user chose not to create one. Exiting.")
+        sys.exit()
+
+#window = tk.Tk()
+#frame = ttk.Frame(window, padding=10)
+#frame.grid()
+#ttk.Label(frame, text="Hello, World!").grid(column=0, row=0)
+#ttk.Button(frame, text="Quit", command=window.destroy).grid(column=0, row=1)
+
+#window.mainloop()