From 3277af2ac5df2f7a85d8978ed99d2c08f824bb3b Mon Sep 17 00:00:00 2001
From: Chewing_Bever <roosensjef@gmail.com>
Date: Sun, 25 Apr 2021 18:10:37 +0200
Subject: [PATCH] Documented skeleton.py

---
 app/skeleton.py        | 55 ++++++++++++++++++++++++++++++++++++++----
 app/specs/directory.py |  4 +--
 2 files changed, 51 insertions(+), 8 deletions(-)

diff --git a/app/skeleton.py b/app/skeleton.py
index 07c6afb..9fe48a6 100644
--- a/app/skeleton.py
+++ b/app/skeleton.py
@@ -1,21 +1,55 @@
+"""Handles merging with the skeleton config."""
 from typing import Dict
 
 
 class InvalidKeyError(Exception):
-    def __init__(self, key):
+    """Thrown when a config file contains an invalid key."""
+
+    def __init__(self, key: str):
+        """
+        Create a new InvalidKeyError object with the given key.
+
+        Args:
+            key: the invalid key
+        """
         self.message = "Invalid key: {}".format(key)
 
         super().__init__(key)
 
 
 class MissingKeyError(Exception):
-    def __init__(self, key):
+    """Thrown when a required key is missing from a config."""
+
+    def __init__(self, key: str):
+        """
+        Create a new MissingKeyError object with the given key.
+
+        Args:
+            key: the invalid key
+        """
         self.message = "Missing key: {}".format(key)
 
         super().__init__(key)
 
 
 def merge(*dicts: [Dict]) -> Dict:
+    """
+    Merge multiple dicts into one.
+
+    It reads the dicts from left to right, always preferring the "right"
+    dictionary's values. Therefore, the dictionaries should be sorted from
+    least important to most important (e.g. a default values skeleton should be
+    to the left of a dict of selected values).
+
+    Args:
+        dicts: the dictionaries to merge
+
+    Returns:
+        a new dictionary representing the merged dictionaries
+
+    Todo:
+        * Make sure an infinite loop is not possible
+    """
     # Base cases
     if len(dicts) == 0:
         return {}
@@ -45,10 +79,20 @@ def merge(*dicts: [Dict]) -> Dict:
 
 def merge_with_skeleton(data: Dict, skel: Dict) -> Dict:
     """
-    Compare a dict with a given skeleton dict, and fill in default values where
-    needed.
-    """
+    Merge a dictionary with a skeleton containing default values.
 
+    The skeleton not only defines what the default values are, but also
+    enforces a certain shape. This allows us to define a config file using a
+    dictionary and parse it.
+
+    Args:
+        data: dictionary containing the selected config values
+        skel: dictionary containing the skeleton (aka the def)
+
+    Todo:
+        * Check if an infinite loop is possible
+        * Split info less complex functions
+    """
     # First, check for illegal keys
     for key in data:
         if key not in skel:
@@ -66,6 +110,7 @@ def merge_with_skeleton(data: Dict, skel: Dict) -> Dict:
 
         # Error if value is not same type as default value
         elif type(data[key]) != type(value) and value is not None:
+            # TODO make this error message more verbose
             raise TypeError("Invalid value type")
 
         # Recurse into dicts
diff --git a/app/specs/directory.py b/app/specs/directory.py
index 9747b5b..4fa0ffe 100644
--- a/app/specs/directory.py
+++ b/app/specs/directory.py
@@ -6,9 +6,7 @@ from datetime import datetime
 
 
 class DirectorySpec(Spec):
-    """
-    A spec for backing up a local directory.
-    """
+    """A spec for backing up a local directory."""
 
     _SKEL = {
         "source": None,