updated mailroom2 solution

Author: PythonCHB

source/solutions/Lesson04/mailroom2.py

@@ -45,6 +45,14 @@ def list_donors():
     return "\n".join(listing)
 
 
+def print_donor_list():
+    """
+    Doesn't do much, but keeps the printing separate
+    """
+    print(list_donors())
+    print()
+
+
 def find_donor(name):
     """
     Find a donor in the donor db
@@ -68,10 +76,6 @@ def add_donor(name):
     donor_db[name.lower()] = donor
     return donor
 
-
-
-
-
 def gen_letter(donor):
     """
     Generate a thank you letter for the donor
@@ -92,35 +96,35 @@ def gen_letter(donor):
           '''.format(donor[0], donor[1][-1]))
 
 
-def take_donation(name):
+def take_donation():
     """
     Ask user for donation amount, and then add it  to the DB
     """
     # Now prompt the user for a donation amount to apply. Since this is
     # also an exit point to the main menu, we want to make sure this is
     # done before mutating the db.
+    print("in take_donation")
+    name = input("Enter a donor name (new or existing): \n >")
     while True:
-        amount_str = input("Enter a donation amount (or 'menu' to exit)> ").strip()
-        if amount_str == "menu":
+        amount_str = input("Enter a donation amount (or <enter> to exit)> ").strip()
+        if not amount_str:
+            # if they provide no input, go back to previous menu
             return
         # Make sure amount is a valid amount before leaving the input loop
-        try:
-            amount = float(amount_str)
-            # extra check here -- unlikely that someone will type "NaN", but
-            # it IS possible, and it is a valid floating point number:
-            # http://en.wikipedia.org/wiki/NaN
-            if math.isnan(amount) or math.isinf(amount) or round(amount, 2) == 0.00:
-                raise ValueError
-        # in this case, the ValueError could be raised by the float() call, or by the NaN-check
-        except ValueError:
+        amount = float(amount_str)
+        # extra check here -- unlikely that someone will type "NaN", but
+        # it IS possible, and it is a valid floating point number:
+        # http://en.wikipedia.org/wiki/NaN
+        if math.isnan(amount) or math.isinf(amount) or round(amount, 2) == 0.00:
             print("error: donation amount is invalid\n")
+            continue
         else:
             break
 
-    # If this is a new user, ensure that the database has the necessary
-    # data structure.
     donor = find_donor(name)
+    # If the donor is not found, it's a new donor
     if donor is None:
+        # add the new donor to the database
         donor = add_donor(name)
 
     # Record the donation
@@ -129,23 +133,6 @@ def take_donation(name):
     print(gen_letter(donor))
 
 
-def send_thank_you():
-    """
-    Execute the logic to record a donation and generate a thank you message.
-    """
-    # Read a valid donor to send a thank you from, handling special commands to
-    # let the user navigate as defined.
-    while True:
-        name = input("Enter a donor's name or 'list' to see all donors or "
-                     "'menu' to exit to main menu > ").strip()
-        if name == "list":
-            print(list_donors())
-        elif name == "menu":
-            return
-        else:
-            take_donation(name)
-
-
 def sort_key(item):
     # used to sort on name in donor_db
     return item[1]
@@ -194,6 +181,10 @@ def print_donor_report():
     print(generate_donor_report())
 
 
+def return_to_menu():
+    ''' Return True to trigger exit out of sub-loop'''
+    return True
+
 def quit():
     """
     quit the program
@@ -203,6 +194,21 @@ def quit():
     """
     sys.exit(0)
 
+def send_thank_you():
+    """
+    Execute the logic to record a donation and generate a thank you message.
+    """
+    # Read a valid donor to send a thank you from, handling special commands to
+    # let the user navigate as defined.
+    prompt = ("To send a thank you, select one:\n\n"
+              "(1) Update donor and send thank-you\n"
+              "(2) List all existing DONORS\n"
+              "(3) Return to main menu\n > ")
+    selection_dict = {"1": take_donation,
+                      "2": print_donor_list,
+                      "3": return_to_menu,
+                      }
+    run_menu(prompt, selection_dict)
 
 def main_menu():
     """
@@ -211,10 +217,10 @@ def main_menu():
     prompt = dedent('''
                     Choose an action:
 
-                    1 - Send a Thank You
-                    2 - Create a Report
-                    3 - Send letters to everyone
-                    4 - Quit
+                    (1) - Send a Thank You
+                    (2) - Create a Report
+                    (3) - Send letters to everyone
+                    (4) - Quit
 
                     > ''')
 
@@ -236,13 +242,15 @@ def run_menu(prompt, selection_dict):
                            the actions to take.
     """
     while True:
-
-        selection = input(prompt).strip()
-        try:
-            # This calls teh function in the selection_dict
-            selection_dict[selection]()
-        except KeyError:
+        selection = input(prompt).strip().lower()
+        action = selection_dict.get(selection, None)
+        if action is None:
             print("error: menu selection is invalid!")
+        else:
+            if action():
+                # break out of the loop if action returns True
+                break
+
 
 if __name__ == "__main__":