Added main code of animal game

(not fully tested)

03 Animal/python/animal.py

@@ -0,0 +1,94 @@
+class Node:
+    """
+    Nodes of the binary tree of questions.
+    """
+
+    def __init__(self, text, yes_node, no_node, is_leaf):
+        self.text = text
+        self.yes_node = yes_node
+        self.no_node = no_node
+        # the nodes that are leafs have as text the animal's name
+        self.is_leaf = is_leaf
+
+    def update_node(self, new_question, answer_new_ques, new_animal):
+        # update the yes or no leaf with a question
+        old_animal = self.text
+        # we replace the animal with a new question
+        self.text = new_question
+
+        if answer_new_ques == 'y':
+            self.yes_node = Node(new_animal, None, None, True)
+            self.no_node = Node(old_animal, None, None, True)
+        else:
+            self.yes_node = Node(old_animal, None, None, True)
+            self.no_node = Node(new_animal, None, None, True)
+
+        self.is_leaf = False
+
+
+def parse_input(message):
+    # only accepts yes or no inputs
+    correct_input = False
+    while not correct_input:
+        try:
+            inp = input(message)
+            token = inp[0].lower()
+            if token == 'y' or token == 'n':
+                correct_input = True
+        except IndexError:
+            pass
+
+    return token
+
+
+def avoid_void_input(message):
+    answer = ''
+    while answer == '':
+        answer = input(message)
+    return answer
+
+
+# Initial tree
+yes_child = Node('Fish', None, None, True)
+no_child = Node('Bird', None, None, True)
+root = Node('Does it swim?', yes_child, no_child, False)
+
+# Main loop of game
+keep_playing = parse_input('Are you thinking of an animal?') == 'y'
+while keep_playing:
+    keep_asking = True
+    # Start traversing the tree by the root
+    actual_node = root
+
+    while keep_asking:
+
+        if not actual_node.is_leaf:
+            # we have to keep asking i.e. traversing nodes
+            answer = parse_input(actual_node.text)
+
+            if answer == 'y':
+                actual_node = actual_node.yes_node
+            else:
+                actual_node = actual_node.no_node
+        else:
+            # we have reached a possible answer
+            answer = parse_input('Is it a {}?'.format(actual_node.text))
+            if answer == 'n':
+                # add the animal to the tree
+                new_animal = avoid_void_input(
+                    'The animal you were thinking of was a ?')
+                new_question = avoid_void_input(
+                    'Please type in a question that would distinguish a {} from a {}:'.format(new_animal, actual_node.text))
+                print("new_animal:" + new_animal)
+                answer_new_question = parse_input(
+                    'for a {} the answer would be:'.format(new_animal))
+
+                actual_node.update_node(
+                    new_question+'?', answer_new_question, new_animal)
+
+            else:
+                print("Why not try another animal?")
+
+            keep_asking = False
+
+    keep_playing = parse_input('Are you thinking of an animal?') == 'y'