Added a utility function which transform a string into another which …

…can be used in a regex without any special matching behavior other than matching the original string.

src/hopen/syntax/util.cljc

@@ -0,0 +1,10 @@
+(ns hopen.syntax.util
+  (:require [clojure.string :as str]))
+
+(defn re-quote
+  "Escapes characters in the string that are not safe to use in a regex.
+   Function ported to Clojure from https://github.com/google/closure-library/blob/0257667129eded0cb9b86b4701e50c986b5db648/closure/goog/string/string.js#L1016"
+  [s]
+  (-> s
+      (str/replace #"[-()\[\]{}+?*.$\^|,:#<!\\]" #(str "\\" %))
+      (str/replace #"\x08", "\\x08")))

test/hopen/runner.cljs

@@ -2,7 +2,9 @@
   (:require  [cljs.test :as t :include-macros true]
              [doo.runner :refer-macros [doo-all-tests doo-tests]]
              [hopen.renderer.xf-test]
+             [hopen.syntax.util-test]
              [hopen.util-test]))
 
 (doo-tests 'hopen.renderer.xf-test
+           'hopen.syntax.util-test
            'hopen.util-test)

test/hopen/syntax/util_test.cljc

@@ -0,0 +1,13 @@
+(ns hopen.syntax.util-test
+  (:require #?(:clj  [clojure.test :refer [deftest testing is are]]
+               :cljs [cljs.test    :refer [deftest testing is are]
+                      :include-macros true])
+            [hopen.syntax.util :refer [re-quote]]))
+
+(deftest re-quote-test
+  (are [input output]
+    (= (re-quote input) output)
+
+    "bonjour" "bonjour"
+    "{{}}" "\\{\\{\\}\\}"
+    "<%%>" "\\<%%>"))