Learn Datalog Today REPL Fiddle

repl_fiddle.clj

(ns learndatalogtoday.repl-fiddle
  (:require [learndatalogtoday.handler :as handler]
            [datomic.client.api :as d]))

(defn exercise-chapter [n]
  (reduce (fn [acc {:keys [question inputs :as exercise]}]
            (conj acc [(count acc)
                       question ((fn [[query & args]]
                                   (list 'comment
                                         (apply list
                                                (cond-> ['d/q \' (:value query) 'db]
                                                  (seq args) (into (map :value args))))))
                                 inputs)]))
          []
          (:exercises (handler/read-chapter n))))

(defn give-up [ch ex]
  (-> ch
      (handler/read-chapter)
      :exercises
      (get ex)
      :inputs
      first
      :correct-value))

(def schema (handler/read-file "db/schema.edn"))
(def seed-data (handler/read-file "db/data.edn"))
(def db (handler/init-db "movies" schema seed-data))

(comment 
  
  (exercise-chapter 0) ; Evaluate to ignore
  #_[[0 "Find all movies titles in the database." 
      (comment (d/q \' [:find ...] db))]]
  ;; Then remove ignore marker and the backslash, and add newlines wherever it makes sense

  (give-up 0 0) ; Evaluate to peek
  
  :rcf)

For fiddling with https://www.learndatalogtoday.org/ exercises in the REPL.

0. Clone https://github.com/jonase/learndatalogtoday to your machine
1. Start the REPL
2. Load this file in the REPL
3. Read a chapter on https://www.learndatalogtoday.org/ (or run the server locally if you're on a plane, say)
4. Evaluate stuff like (exercise-chapter 0) to ignores, do some little cleanup
5. Edit the query and evaluate the (d/q ...) forms

More resources:

• Datalog Links and Notes
• Asami Introduction

It breaks down at chapter 9, I now notice. 😄

If you run the server locally, you can submit an exercise for chapter 9, without editing the placeholder rules, and look at the stdout from the REPL to see what your (d/q ...) expression should look like.