From 5bfe0b15860089b58a6a610996cecf33edf8610d Mon Sep 17 00:00:00 2001
From: Alan Dipert <alan@dipert.org>
Date: Fri, 21 Oct 2011 11:05:47 -0400
Subject: [PATCH] data conveying exception

---
 src/clj/clojure/core.clj                |   24 ++++++++++++++++++
 src/clj/clojure/repl.clj                |    4 ++-
 src/jvm/clojure/lang/ExceptionInfo.java |   40 +++++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+), 1 deletions(-)
 create mode 100644 src/jvm/clojure/lang/ExceptionInfo.java

diff --git a/src/clj/clojure/core.clj b/src/clj/clojure/core.clj
index b1801e9..b1fe5cd 100644
--- a/src/clj/clojure/core.clj
+++ b/src/clj/clojure/core.clj
@@ -4220,6 +4220,30 @@
     (with-out-str
      (apply println xs)))
 
+(import clojure.lang.ExceptionInfo)
+(defn ex-info
+  "Alpha - subject to change.
+   Create an instance of ExceptionInfo, a RuntimeException subclass
+   that carries a map of additional data."
+  {:added "1.4"}
+  ([msg map]
+     (if (map? map)
+       (ExceptionInfo. msg map)
+       (throw (IllegalArgumentException. (str "Additional data must be a map: " map)))))
+  ([msg map cause]
+     (if (map? map)
+       (ExceptionInfo. msg map cause)
+       (throw (IllegalArgumentException. (str "Additional data must be a map: " map))))))
+
+(defn ex-data
+  "Alpha - subject to change.
+   Returns exception data (a map) if ex is an ExceptionInfo.
+   Otherwise returns nil."
+  {:added "1.4"}
+  [ex]
+  (when (instance? ExceptionInfo ex)
+    (.getData ^ExceptionInfo ex)))
+
 (defmacro assert
   "Evaluates expr and throws an exception if it does not evaluate to
   logical true."
diff --git a/src/clj/clojure/repl.clj b/src/clj/clojure/repl.clj
index 3218180..af55a2f 100644
--- a/src/clj/clojure/repl.clj
+++ b/src/clj/clojure/repl.clj
@@ -251,7 +251,9 @@ str-or-pattern."
          (pst (root-cause e) e-or-depth))))
   ([^Throwable e depth]
      (binding [*out* *err*]
-       (println (str (-> e class .getSimpleName) " " (.getMessage e)))
+       (println (str (-> e class .getSimpleName) " "
+                     (.getMessage e)
+                     (when-let [info (ex-data e)] (str " " info))))
        (let [st (.getStackTrace e)
              cause (.getCause e)]
          (doseq [el (take depth
diff --git a/src/jvm/clojure/lang/ExceptionInfo.java b/src/jvm/clojure/lang/ExceptionInfo.java
new file mode 100644
index 0000000..1f6acc2
--- /dev/null
+++ b/src/jvm/clojure/lang/ExceptionInfo.java
@@ -0,0 +1,40 @@
+/**
+ * Copyright (c) Rich Hickey. All rights reserved.
+ * The use and distribution terms for this software are covered by the
+ * Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+ * which can be found in the file epl-v10.html at the root of this distribution.
+ * By using this software in any fashion, you are agreeing to be bound by
+ * the terms of this license.
+ * You must not remove this notice, or any other, from this software.
+ */
+
+package clojure.lang;
+
+import java.util.Map;
+
+/**
+ * Exception that carries data (a map) as additional payload. Clojure programs that need
+ * richer semantics for exceptions should use this in lieu of defining project-specific
+ * exception classes.
+ */
+public class ExceptionInfo extends RuntimeException{
+    public final IPersistentMap data;
+
+    public ExceptionInfo(String s, IPersistentMap data) {
+        super(s);
+        this.data = data;
+    }
+
+    public ExceptionInfo(String s, IPersistentMap data, Throwable throwable) {
+        super(s, throwable);
+        this.data = data;
+    }
+
+    public IPersistentMap getData() {
+        return data;
+    }
+
+    public String toString() {
+        return "clojure.lang.ExceptionInfo: " + getMessage() + " " + data.toString();
+    }
+}
-- 
1.7.6