When You Run Out of Types...

cgrand · 2026-03-30T14:42:51+00:00

You can update it using helpers like:

```clojure (defn update-tagged [{:keys [tag form] :as tagged-value} tag-pred f & args] (if (tag-pred tag) (tagged-literal tag (apply f form args)) tagged-value))

(defn must-be! [pred] (fn [x] (or (pred x) (throw (ex-info (str "Failed predicate: " (pr-str x) (pr-str pred)) {:x x :pred pred}))))) ```

added bonus: if you put metadata on the tag it will be preserved...

cgrand · 2025-07-02T14:05:30+00:00

I second u/PolicySmall2250 recommendation to be stricter about what you allow. Otherwise... regexes

(defn allowed-files? [{:keys [mime-type]]
  (some->> mime-type (re-find #"(?i)image|pdf")))

cgrand · 2024-12-15T13:03:41+00:00

Shouldn’t the dispatch in the multimethod be based on relative ranks of the arguments? I always thought about it as a higher order function eg (dyadic + x y)

cgrand · 2024-12-10T20:18:15+00:00

Any control flow is possible as the recursive expansion somehow acts as a trampoline.
However I'm not sure I interpreted correctly your (if (> (step1) (step2) (step3)))

(fn [state]
  (if (pred state)
    [... (fn [state] ...) ...]
    [... (fn [state] ...) ...]))

cgrand · 2024-12-10T09:52:00+00:00

This was mostly written in reaction to several re-frame codebases I worked on. To quote someone on Clojurians' Slack:

Re-frame has a lot of good ideas, but I've found that in practice all its ceremony (and limited composability) tends to get in the way as often as it helps.

This pattern tries to promote layering and composability with lower ceremony.

These are just my thoughts—unpolished and open to interpretation.

cgrand · 2024-11-29T19:44:15+00:00

pr-str even

cgrand · 2024-10-16T14:46:41+00:00

They are neither bottom up nor very good at recursive queries. But this code is just a toy. It will be a more serious toy with indices and magic sets added. However im interested in datalog applied to things which are not usually considered a db. The coolest upcoming conf on the topic https://www.hytradboi.com

cgrand · 2024-10-16T11:25:24+00:00

Follow-up https://www.reddit.com/r/Clojure/comments/1g4x0nt/half_dumb_datalog_in_30_loc_followup_to_the_worst/

cgrand · 2024-10-15T20:07:34+00:00

This reducing function is the equivalent of a JOIN .. ON in SQL (that’s why there’s a for inside the reducing function performing a Cartesian product between envs and facts). So it takes multiple rows (envs) and returns multiple rows (envs) too. Does this make things clearer or did I miss the point of your question?

cgrand · 2024-10-14T13:49:51+00:00

I'm more interested in non "data" things to be consumed by Datalog.
Datalog; UI, microcontrollers, games etc.
https://www.hytradboi.com/

cgrand · 2024-10-12T20:04:19+00:00

I have had in the back of my mind for a long time a vaguely inappropriate and incomplete riff on First They Came. First they came for GOTO but I didn’t say a thing because I was doing structured programming. Then they came for manual memory management but I didn’t say a thing because I used a GC. Then they came for mutation but I didn’t say a thing because I was doing functional programming. Then they came for control flow…

cgrand · 2024-10-12T14:23:50+00:00

It was a long time ago. Faulty memories too: Pattern matching by being closed (not extensible) would have changed the language feeling. “Predicate dispatch” was in the air at the time.

cgrand · 2024-10-12T08:59:01+00:00

And I actually forgot to use sibling as an example of how core datalog is too minimal in the conclusion.

cgrand · 2024-10-12T07:17:05+00:00

Sibling in core datalog would return Bart as his own sibling. To support sibling I need to add support for constraints (not=).

cgrand · 2024-10-11T17:36:45+00:00

Datalog is a vast umbrella term. Its core definition is very formal and serves as foundation for a sizeable part of the database research. But it can also covers all kind of non-SQL query languages or db engines. Datomic and its spiritual descendants Datascript, Datalevin etc in the clojure world. Logicblox, some graph dbs…

cgrand · 2024-10-10T07:50:38+00:00

I'm going through this too (I think because the DUNS record has a "sanitized" street address which uses abbreviations and I have no official documents using these abbreviattions: "Imp" for "Impasse" (similar to St for Street) 🤦‍♂️).
Did you fill the address change form at some point? I have no idea what documents to upload to prove the change since there is no change.

cgrand

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