Added invalidation helpers + `::cache` meta to `defcached` and `cached` by Aeonax · Pull Request #10 · fmnoise/coldbrew

Aeonax · 2025-03-28T11:01:01Z

No description provided.

fmnoise · 2025-04-15T09:19:42Z

src/fmnoise/coldbrew.clj

      (.build cache-builder (cache-loader cache-fn))
      (.build cache-builder))))

+(defn get-cache-keys


cache-keys maybe?

cache-keys still sounds a bit too general to me — feels like it’s missing the ‘action’ part a function name usually has.

But after chatting with ChatGPT, I can see that cache-keys actually fits more with the Clojure style — like meta, keys, and so on 🤔

fmnoise · 2025-04-15T09:25:12Z

src/fmnoise/coldbrew.clj

  [^Cache cache key]
  (.invalidate cache key))

+(defn invalidate-keys


I'm thinking if invalidate-all could be better name to mimic native call, but feels like all is a bit misleading because it's not "all" but listed ones 🤔

Yeah, that is why I named it this way - invalidate-all looks too bad for my liking😅🙈 Of course, we can have, for example, invalidate-all with 2 arities - cache + cache keys. Then it will be a bit more logical, but still...

I'm now thinking maybe we should allow passing caching function as an argument 🤔

What do you mean?

I mean we're passing cache here, but what if we'll pass function, and this functions will extract cache using the implementation details

fmnoise · 2025-04-15T09:26:26Z

src/fmnoise/coldbrew.clj

+                                  ~@body)
+                                ~cache-options)))
+       (defn ~@fdefn (~fname ~@cache-key))
+       (alter-meta! (var ~name) merge (meta ~fname) ~(meta name)))))


interesting, does alter-meta! fit better than vary-meta here?

As I mentioned in PM, looks like vary-meta returns a new object with altered meta - it doesn't mutate the initial def, so it did nothing. Meta passed to defcache persisted without vary-meta help.
Unless I missed some corner case, or something else... Because this angle of interaction with meta is a bit new to me.

yes, vary-meta returns new object, same as with-meta, while alter-meta! does meta mutation, but it works on var reference level rather than the object level, so I'm not sure it will work good with 2 different approaches - object meta association on caching function using with-meta and then on var reference using alter-meta!

also I can't remember which kind of meta did we pass on that function and for the sake of what 😅
probably just normal function meta non-related to caching at all

I don't remember whether I tested all possibilities, but as I remember, in this case, I could have used (alter-meta! (var ~name) merge (meta ~fname)) because even without name, meta persisted well.

fmnoise · 2025-04-15T09:27:40Z

src/fmnoise/coldbrew.clj

  (let [options (meta f)
        condition-fn (-> f meta :when)
        cache (build-cache options (when-not condition-fn f))]
+    ^{::cache cache}


I feel like it's pretty much an implementation detail, so maybe we could add a helper for getting cache from the function using the meta? 🤔

It is a bit tricky, but I did it=) Question is how to name it... too many caches in naming🤔 get-defcache-cache or defcache-cache or defcache-cache-object or ......

Ah, there is a cached function too, so I need to add a helper for both defcache and cached🤔

now I feel like maybe storing cache in function meta/var meta is a bit messy way 🤔
maybe we could have caches registry in atom or volatile, which could allow us to have more tooling for monitoring caches size 🤔
and we could probably use defcached fully qualified function name for the cache key in the registry 🤔
but I'm not sure how should we put the cache into registry when using cached 🤔
maybe we should just add something like cache-id for manipulating the cache, and that would allow us to get rid of cached->cache or anything like that, allowing just to pass cache-id when creating cache and then using it with cache-keys and invalidate-keys 🤔

Personally, I prefer meta because:

It exists on the same level of execution - just a part of the result

There's no extra complexity with cache IDs, storage layers, etc.

I was able to link it to the source caching object with minimal changes, and having access to that caching object is all I need right now.

Yes, integrating this meta into defcached and accessing it can be a bit tricky, but it works. And for the end user, it’s just a cached->cache or defcached->cached.

That said, if you have a clear idea for a different approach, I’d be really interested to see how it turns out =)

meta is convenient, but it's way more complicated than it seems, as it could be attached to the object, but only of certain types, and passed along with it, and also to refs (vars, namespaces etc) which has completely different semantics and can contain objects of any type including nil 🤷🏽‍♂️
so, more straightforward way could be giving cache meaningful id, if you'll ever need to work with it and some clear way to access cache by id

fmnoise · 2025-04-24T16:10:56Z

src/fmnoise/coldbrew.clj

          (cond-lookup cache key condition-fn f args)
          (lookup cache key))))))

+(defn cached-cache [cached-fn]


sounds like oily-oil 🙈
I'd try something like cached->cache or fn->cache

fmnoise · 2025-04-24T16:19:28Z

src/fmnoise/coldbrew.clj

+       (defn ~@fdefn (~fname ~@cache-key))
+       (alter-meta! (var ~name) merge (meta ~fname) ~(meta name)))))
+
+(defmacro defcached-cache [defcache-fn]


a bit weird name, and I don't fully understand what's the use-case
but the use-case if probably related to the way we store meta - on function object or var ref, which adds more confusion 😞

fmnoise · 2025-04-24T16:23:16Z

src/fmnoise/coldbrew.clj

+                                  ~@body)
+                                ~cache-options)))
+       (defn ~@fdefn (~fname ~@cache-key))
+       (alter-meta! (var ~name) merge (meta ~fname) ~(meta name)))))


also I can't remember which kind of meta did we pass on that function and for the sake of what 😅
probably just normal function meta non-related to caching at all

fmnoise · 2025-04-24T16:28:05Z

src/fmnoise/coldbrew.clj

  [^Cache cache key]
  (.invalidate cache key))

+(defn invalidate-keys


I'm now thinking maybe we should allow passing caching function as an argument 🤔

fmnoise · 2025-04-24T16:34:41Z

src/fmnoise/coldbrew.clj

  (let [options (meta f)
        condition-fn (-> f meta :when)
        cache (build-cache options (when-not condition-fn f))]
+    ^{::cache cache}


now I feel like maybe storing cache in function meta/var meta is a bit messy way 🤔
maybe we could have caches registry in atom or volatile, which could allow us to have more tooling for monitoring caches size 🤔
and we could probably use defcached fully qualified function name for the cache key in the registry 🤔
but I'm not sure how should we put the cache into registry when using cached 🤔
maybe we should just add something like cache-id for manipulating the cache, and that would allow us to get rid of cached->cache or anything like that, allowing just to pass cache-id when creating cache and then using it with cache-keys and invalidate-keys 🤔

fmnoise · 2025-05-11T21:24:39Z

src/fmnoise/coldbrew.clj

+                                (fn [~@cache-key]
+                                  ~@body)
+                                ~cache-options)))
+       (defn ~@fdefn (~fname ~@cache-key))


maybe should apply cache metadata taken from (meta ~fname) to this function object rather than applying it to var?

something like

(def ~name (with-meta (fn ~@(when docstring [docstring]) ~@(when prepost [prepost]) [~@args] (~fname ~@cache-key)) (meta ~fname)))))

my idea here is to always put cache meta on function object, so when we need to get cache, we can use only function instead of 2 approaches: function and var

Looks interesting!🤔 I didn't want to fight with all those variables, but it doesn't look as bad as I imagined.

I'm busy with other stuff this week, but on the next week I should be able to return into this pr.

Aeonax added 3 commits March 28, 2025 11:46

Added get-cache-keys and invalidate-keys

2d0adce

Added ::cache meta to cached and defcached

9f77eb5

Added tests for meta

57fd5aa

Aeonax force-pushed the invalidation-helpers branch from 9b24046 to 57fd5aa Compare March 28, 2025 12:03

fmnoise reviewed Apr 15, 2025

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Aeonax added 2 commits April 16, 2025 10:48

Added helpers to access cache object

1defc80

Renamed get-cache-keys to cache-keys

01adbc2

Aeonax requested a review from fmnoise April 16, 2025 08:50

fmnoise reviewed Apr 24, 2025

View reviewed changes

fmnoise reviewed May 11, 2025

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Aeonax commented Mar 28, 2025

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fmnoise May 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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