fixed pop and metadata semantics

1 files changed, 12 insertions, 9 deletions

diff --git a/src/jvm/clojure/lang/PersistentList.java b/src/jvm/clojure/lang/PersistentList.java
index c7331ef5..f1130195 100644
--- a/src/jvm/clojure/lang/PersistentList.java
+++ b/src/jvm/clojure/lang/PersistentList.java
@@ -28,13 +28,6 @@ public PersistentList(Object first){
 	this._count = 1;

 }

 

-PersistentList(Object first, PersistentList rest){

-	this._first = first;

-	this._rest = rest;

-

-	this._count = 1 + rest.count();

-}

-

 PersistentList(IPersistentMap meta, Object _first, PersistentList _rest, int _count){

 	super(meta);

 	this._first = _first;

@@ -59,12 +52,18 @@ public ISeq rest(){
 	return _rest;

 }

 

+public IPersistentList pop(){

+	if(_rest == null)

+		return EMPTY.withMeta(meta());

+	return _rest;

+}

+

 public int count(){

 	return _count;

 }

 

 public ISeq cons(Object o){

-	return new PersistentList(o, this);

+	return new PersistentList(meta(), o, this, _count + 1);

 }

 

 public PersistentList withMeta(IPersistentMap meta){

@@ -78,7 +77,7 @@ static class EmptyList extends PersistentList{
 	}

 

 	public ISeq cons(Object o){

-		return new PersistentList(o, null);

+		return new PersistentList(meta(), o, null, 1);

 	}

 

 	public PersistentList withMeta(IPersistentMap meta){

@@ -87,6 +86,10 @@ static class EmptyList extends PersistentList{
 		return this;

 	}

 

+	public IPersistentList pop(){

+		throw new IllegalStateException("Can't pop empty list");

+	}

+

 	public ISeq seq(){

 		return null;

 	}