Current state of mal for Clojure West lighting talk.

1 files changed, 32 insertions, 0 deletions

diff --git a/clojure/src/reader.clj b/clojure/src/reader.clj
new file mode 100644
index 0000000..8f14767
--- /dev/null
+++ b/clojure/src/reader.clj
@@ -0,0 +1,32 @@
+(ns reader
+    (:refer-clojure :exclude [read-string])
+    (:require [clojure.tools.reader :as r]
+              [clojure.tools.reader.reader-types :as rt]))
+
+;; change tools.reader syntax-quote to quasiquote
+(defn- wrap [sym]
+  (fn [rdr _] (list sym (#'r/read rdr true nil true))))
+
+(defn- wrap-with [sym]
+  (fn [rdr arg _] (list sym (#'r/read rdr true nil true) arg)))
+
+;; Override some tools.reader reader macros so that we can do our own
+;; metadata and quasiquote handling
+(alter-var-root #'r/macros
+  (fn [f]
+    (fn [ch]
+      (case ch
+        \` (wrap 'quasiquote)
+        \~ (fn [rdr comma]
+             (if-let [ch (rt/peek-char rdr)]
+               (if (identical? \@ ch)
+                 ((wrap 'splice-unquote) (doto rdr rt/read-char) \@)
+                 ((wrap 'unquote) rdr \~))))
+        \^ (fn [rdr comma]
+             (let [m (#'r/read rdr)]
+               ((wrap-with 'with-meta) rdr m \^)))
+        \@ (wrap 'deref)
+        (f ch)))))
+
+(defn read-string [s]
+  (r/read-string s))