diff --git a/cache.rkt b/cache.rkt
index b4ed9fe..6fe162d 100644
--- a/cache.rkt
+++ b/cache.rkt
@@ -1,44 +1,46 @@
 #lang racket/base
 (require racket/rerequire)
-;(require racket/contract)
 (require "debug.rkt" sugar/coerce)
 
-(provide current-cache make-cache cached-require get-cache-hash)
+;; The cache is a hash with paths as keys.
+;; The cache values are also hashes, with key/value pairs for that path.
 
+(provide current-cache make-cache cached-require cache-ref)
+
+;; Don't initialize a cache when the module is loaded. This induces reliance.
+;; The cache only makes sense if a single one is used across a whole session (e.g., via parameterize).
 (define current-cache (make-parameter #f))
 
-(define (make-cache)
- ; ( ->  hash?)
-  (make-hash))
+(define (make-cache) (make-hash))
 
-(define (get-cache-hash path-string)
- ; (path-string? . -> . hash?)
+(define (cache-ref path-string)
   (hash-ref (current-cache) (->complete-path path-string)))
 
-(define (cache-ref path sym)
- ; (path? symbol? . -> . any/c)
-  (hash-ref (get-cache-hash path) sym))
+(define (cache-has-key? path)
+  (hash-has-key? (current-cache) path))
+
 
-(define (cached-require path-string sym)
- ; (path-string? symbol? . -> . any/c)
+(define (cached-require path-string key)
   (when (not (current-cache)) (error "cached-require: No cache set up."))
   
-  (define path (->complete-path path-string))
+  (define path 
+    (with-handlers ([exn:fail? (λ(exn) (displayln (format "cached-require: ~a is not a valid path" path-string)))])
+      (->complete-path path-string)))
   
   (define (cache path)
     (dynamic-rerequire path)
     (hash-set! (current-cache) path (make-hash))
-    (define cache-hash (hash-ref (current-cache) path))
+    (define cache-hash (cache-ref path))
     (hash-set! cache-hash 'mod-time (file-or-directory-modify-seconds path))
     (hash-set! cache-hash 'main (dynamic-require path 'main))
     (hash-set! cache-hash 'metas (dynamic-require path 'metas))
     (void))
   
-  (when (or (not (hash-has-key? (current-cache) path))
-            (> (file-or-directory-modify-seconds path) (hash-ref (hash-ref (current-cache) path) 'mod-time)))
+  (when (or (not (cache-has-key? path))
+            (> (file-or-directory-modify-seconds path) (hash-ref (cache-ref path) 'mod-time)))
     (cache path))
   
-  (cache-ref path sym))
+  (hash-ref (cache-ref path) key))
 
 
 
diff --git a/debug.rkt b/debug.rkt
index aad754b..baab40c 100644
--- a/debug.rkt
+++ b/debug.rkt
@@ -73,3 +73,6 @@
 (make-message-logger-functions warning)
 (make-message-logger-functions info)
 (make-message-logger-functions debug)
+
+(define+provide (message . items)
+             (displayln (string-join `(,(make-debug-timestamp) ,@(map (λ(x)(if (string? x) x (format "~v" x))) items)))))
\ No newline at end of file