From 858189e4ff7dec5adc0ebef5ff31e971592f3f45 Mon Sep 17 00:00:00 2001
From: Tom Kooij <tomkooij@tomkooij.nl>
Date: Mon, 1 Jan 2018 09:37:36 +0100
Subject: [PATCH 1/2] _Cache is a minimal subclass of dict()

Create an object that can be added to a list by reference,
but preserve dict() functionality.
---
 checkpy/caches.py | 27 ++++++---------------------
 1 file changed, 6 insertions(+), 21 deletions(-)

diff --git a/checkpy/caches.py b/checkpy/caches.py
index 635ea05..f3a010c 100644
--- a/checkpy/caches.py
+++ b/checkpy/caches.py
@@ -2,28 +2,13 @@
 
 _caches = []
 
-class _Cache(object):
-	def __init__(self):
-		self._cache = {}
-		_caches.append(self)
-
-	def __setitem__(self, key, value):
-		self._cache[key] = value
-
-	def __getitem__(self, key):
-		return self._cache.get(key, None)
 
-	def __contains__(self, key):
-		return key in self._cache
-
-	def delete(self, key):
-		if key not in self._cache:
-			return False
-		del self._cache[key]
-		return True
+class _Cache(dict):
+	"""A dict() subclass that appends a self-reference to _caches"""
+	def __init__(self, *args, **kwargs):
+		super(_Cache, self).__init__(*args, **kwargs)
+		_caches.append(self)
 
-	def clear(self):
-		self._cache.clear()
 
 """
 cache decorator
@@ -48,7 +33,7 @@ def cachedFuncWrapper(*args, **kwargs):
 
 			if key not in localCache:
 				localCache[key] = func(*args, **kwargs)
-				
+
 			return localCache[key]
 		return cachedFuncWrapper
 	return cacheWrapper

From f56dc575d003b5611a6b502db80dfd3a914f6c62 Mon Sep 17 00:00:00 2001
From: Tom Kooij <tomkooij@tomkooij.nl>
Date: Mon, 1 Jan 2018 11:07:40 +0100
Subject: [PATCH 2/2] Refactor caches() decorator

Preserve docstrings of cached functions
Use str() to create hashable keys
Update docstring / PEP8
---
 checkpy/caches.py | 33 ++++++++++++++++-----------------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/checkpy/caches.py b/checkpy/caches.py
index f3a010c..4ff35bc 100644
--- a/checkpy/caches.py
+++ b/checkpy/caches.py
@@ -1,4 +1,5 @@
 import sys
+from functools import wraps
 
 _caches = []
 
@@ -10,34 +11,32 @@ def __init__(self, *args, **kwargs):
 		_caches.append(self)
 
 
-"""
-cache decorator
-Caches input and output of a function. If arguments are passed to
-the decorator, take those as key for the cache, otherwise the
-function arguments.
-"""
 def cache(*keys):
-	def cacheWrapper(func, localCache = _Cache()):
+	"""cache decorator
+
+	Caches input and output of a function. If arguments are passed to
+	the decorator, take those as key for the cache. Otherwise use the
+	function arguments and sys.argv as key.
+
+	"""
+	def cacheWrapper(func):
+		localCache = _Cache()
+
+		@wraps(func)
 		def cachedFuncWrapper(*args, **kwargs):
 			if keys:
-				key = keys
+				key = str(keys)
 			else:
-				# treat all collections in kwargs as tuples for hashing purposes
-				values = list(kwargs.values())
-				for i in range(len(values)):
-					try:
-						values[i] = tuple(values[i])
-					except TypeError:
-						pass
-				key = args + tuple(values) + tuple(sys.argv)
+				key = str(args) + str(kwargs) + str(sys.argv)
 
 			if key not in localCache:
 				localCache[key] = func(*args, **kwargs)
-
 			return localCache[key]
 		return cachedFuncWrapper
+
 	return cacheWrapper
 
+
 def clearAllCaches():
 	for cache in _caches:
 		cache.clear()