Add benchmarks to README

diff --git a/README.md b/README.md
index 4779eac75e799bc912ecd0ce11d064866114ee74..c98fc5db4ba52f6aaaef29f285cf3004b2ef9d67 100644 (file)
--- a/README.md
+++ b/README.md
@@ -70,3 +70,54 @@ true
 You can view the full expression
 [here](https://gist.github.com/noprompt/6106573/raw/fcb683834bb2e171618ca91bf0b234014b5b957d/word-re.clj)
 (it's approximately `1.5M`!).
+
+## Benchmarks
+
+```clojure
+(use 'criterium.core)
+
+(def words
+  (-> (io/file "/usr/share/dict/words")
+      io/reader
+      line-seq))
+
+(defn naive-pattern
+  "Create a naive regular expression pattern for matching every string
+   in strs."
+  [strs]
+  (->> strs
+       (clojure.string/join "|")
+       (format "(?:%s)")))
+
+;; Shuffle 10000 words and build a naive and frak pattern from them.
+(def ws (shuffle (take 10000 words)))
+(def n-pat (naive-pattern ws))
+(def f-pat (frak/pattern ws))
+
+;; Verify the naive pattern matches everything it was constructed from.
+(every? #(re-matches n-pat %) ws)
+;; => true
+
+;; Shuffle the words again since the naive pattern is built in the
+;; same order as it's inputs.
+(def ws' (shuffle ws))
+
+;;;; Benchmarks
+
+;; Naive pattern 
+
+(bench (doseq [w ws'] (re-matches n-pat w)))
+
+;;             Execution time mean : 1.499489 sec
+;;    Execution time std-deviation : 181.365166 ms
+;;   Execution time lower quantile : 1.337817 sec ( 2.5%)
+;;   Execution time upper quantile : 1.828733 sec (97.5%)
+
+;; frak pattern
+
+(bench (doseq [w ws'] (re-matches f-pat w)))
+;;             Execution time mean : 155.515855 ms
+;;    Execution time std-deviation : 5.663346 ms
+;;   Execution time lower quantile : 148.168855 ms ( 2.5%)
+;;   Execution time upper quantile : 164.164294 ms (97.5%)
+```