added caching of rest

2 files changed, 26 insertions, 4 deletions

diff --git a/src/cli/runtime/FnSeq.cs b/src/cli/runtime/FnSeq.cs
index 6225cc05..e98a3635 100644
--- a/src/cli/runtime/FnSeq.cs
+++ b/src/cli/runtime/FnSeq.cs
@@ -17,19 +17,30 @@ public class FnSeq : ISeq{
 

 Object _first;

 IFn restFn;

+volatile ISeq _rest;

 

 public FnSeq(Object first, IFn restFn) {

     this._first = first;

     this.restFn = restFn;

-}

+	this._rest = this;

+	}

 

 public Object first() {

     return _first;

 }

 

 public ISeq rest() {

-    return (ISeq) restFn.invoke();

-}

+    if(_rest != this)

+        return _rest;

+    lock(this){

+        if(_rest == this)

+            {

+            _rest = (ISeq) restFn.invoke();

+            restFn = null;

+            }

+        return _rest;

+		}

+    }

 }

 

 }

diff --git a/src/jvm/clojure/lang/FnSeq.java b/src/jvm/clojure/lang/FnSeq.java
index f20dc39c..6f59a437 100644
--- a/src/jvm/clojure/lang/FnSeq.java
+++ b/src/jvm/clojure/lang/FnSeq.java
@@ -14,10 +14,12 @@ public class FnSeq implements ISeq{
 

 Object _first;

 IFn restFn;

+volatile ISeq _rest;

 

 public FnSeq(Object first, IFn restFn) {

     this._first = first;

     this.restFn = restFn;

+    this._rest = this;

 }

 

 public Object first() {

@@ -25,6 +27,15 @@ public Object first() {
 }

 

 public ISeq rest() throws Exception {

-    return (ISeq) restFn.invoke();

+    if(_rest != this)

+        return _rest;

+    synchronized(this){

+        if(_rest == this)

+            {

+            _rest = (ISeq) restFn.invoke();

+            restFn = null;

+            }

+        return _rest;

+    }

 }

 }