OK, this can now compile an index for a single file, and do it very quickly;

it cannot yet iterate over a directory, and I need to work out why not.

But progress!

project.clj

@@ -3,7 +3,8 @@
   :url "http://example.com/FIXME"
   :license {:name "EPL-2.0 OR GPL-2.0-or-later WITH Classpath-exception-2.0"
             :url "https://www.eclipse.org/legal/epl-2.0/"}
-  :dependencies [[org.clojure/clojure "1.11.1"]
+  :dependencies [[dev.weavejester/medley "1.9.0"]
+                 [org.clojure/clojure "1.11.1"]
                  [peco "0.1.6"]]
   :repl-options {:init-ns cc.journeyman.elboob.core}
   :source-paths      ["src/clj"])

resources/ignorable-words.en-GB.edn

@@ -0,0 +1 @@
+ignorable-words.en.edn

src/clj/cc/journeyman/elboob/core.clj

@@ -1,9 +1,43 @@
-(ns cc.journeyman.elboob.core)
+(ns cc.journeyman.elboob.core
+  (:require [clojure.java.io :refer [as-relative-path file resource]]
+            [clojure.string :refer [ends-with?]]
+            [medley.core :refer [deep-merge]]
+            [peco.core :refer [tokenizer]]))
 
-(defn compile
+(defn get-ignorable-words []
+  (let [locale (java.util.Locale/getDefault)
+        tag (.toLanguageTag locale)
+        language (.getLanguage locale)]
+    
+     (first
+      (map #(try (println (format "resources/ignorable-words%s.edn" %))
+                 (read-string
+                  (slurp
+                   (file (format "resources/ignorable-words%s.edn" %))))
+                 (catch Exception e (println (.getMessage e)) nil))
+           [(str "." tag) (str "." language) ""]))))
+
+(defn compile-file
+  "Compile an index for an individual file `f`, tokenised with `tokenise` and 
+   filtered with `ignorable?`."
+  [f tokenise ignorable?]
+  (let [f' (file f)
+        rel (as-relative-path f')
+        tokens (frequencies (remove ignorable? (tokenise (slurp f'))))]
+    (reduce #(assoc %1 %2 {rel (tokens %2)}) {} (keys tokens))))
+
+(defn compile-index
   "scans `dir-paths` as directories of Markdown files. Returns a map which keys
    each lexical token occurring in each file (with Markdown formatting, common
    words, punctuation etc excepted) to a map which keys the relative file path 
    of each file in which the token occurs to the frequency the token occurs within the file."
   [& dir-paths]
-  (println  "Hello, World!"))
+  (let [ignorable-word? (set (get-ignorable-words))
+        tokenise (tokenizer [:lower-case :concat-singles])]
+    (reduce deep-merge {} 
+            (map (fn [dir]
+                   (map #(compile-file % tokenise ignorable-word?) 
+                        (filter 
+                         #(ends-with? (.getName %) ".md")
+                         (file-seq (file dir))))) dir-paths))))
+