diff --git a/examples/lazyseqs.dst b/examples/lazyseqs.dst
index f7d49284..c3d8695f 100644
--- a/examples/lazyseqs.dst
+++ b/examples/lazyseqs.dst
@@ -106,46 +106,38 @@ body once, and then memoizes the result."
    (def thehead (get HEAD x))
    (if thehead (tuple thehead (take-while pred (get TAIL x)))))))
 
-#Iterators is a conscept that looks a lot like lazy seq
-#The following functions turn iterators to lazy seq and vice versa
+# Iterators are a concept that looks a lot like lazy seq
+# The following functions turn iterators to lazy seq and vice versa
 
 (defn- iter-self
-  [next]
-  (delay (tuple (next) (iter-self next))))
+  [next more]
+  (delay 
+   (if (more) (tuple (next) (iter-self next more)))))
 
 (defn iter2lazy
-"Create a lazy sequence froma an iterator"
+"Create a lazy sequence from an iterator"
   [iter]
-  (def  {:more more :next next} iter)
-  (iter-self next))
+  (def {:more more :next next} iter)
+  (iter-self next more))
 
 (defn lazy2iter
   "turn a lazy-seq to an iterator"
   [lazy-seq]
-  (var result (head lazy-seq) )
-  (var  rest (tail lazy-seq))
-  {:more  (fn [] result)
-   :next (fn [] (def next result)
-           (when result
-             (:= result (head rest))
-             (:= rest (tail rest)))
-           next)})
+  (var node lazy-seq)
+  {:more (fn [] (node))
+   :next (fn []
+       (when-let [n (node)]
+        (:= node (get n 1))
+        (get n 0)))})
 
-
-#Now we can use the nonfuctional filter from boot.dst
-#to write a filter version that returns a lazy sequence
-#Be carefull when creating lazy sequences from mutable
-#data structures as their values are references to this
-#data structures. Same is true for iterators
+# Now we can use the non-functional filter from boot.dst
+# to write a filter version that returns a lazy sequence
+# Be careful when creating lazy sequences from mutable
+# data structures as their values are references to this
+# data structures. Same is true for iterators
 
 (defn filter2 [pred coll]
   (tail (iter2lazy (filter pred coll))))
 
-(def arr [0 -1 -2 33 -3 0 302 -3 2 8  54 3 -2 0])
-
-(def filtered (filter2 pos? arr))
-
-(defn run-me [] (realize filtered))
-
-#be carfull with the filter function. First element in (filter pos? arr) is nil
-#last element is false
+# be careful with the filter function. First element in (filter pos? arr) is nil
+# last element is false
diff --git a/src/compiler/boot.dst b/src/compiler/boot.dst
index 310f4158..2727b7b0 100644
--- a/src/compiler/boot.dst
+++ b/src/compiler/boot.dst
@@ -578,6 +578,11 @@ third argument is given"
   (:= current (macroexpand1 current)))
  current)
 
+(defmacro coro
+ "A wrapper for making fibers. Same as (fiber (fn [] ...body))."
+ [& body]
+ (tuple fiber (apply tuple 'fn [] body)))
+
 (defn make-env [parent]
  (def parent (if parent parent _env))
  (def newenv (setproto @{} parent))
@@ -613,19 +618,19 @@ onvalue."
  (var temp nil)
  (var tempval nil)
  # Stream of values
- (def f (fiber (fn []
-    (def p (parser 1)) 
-    (while going
-      (select (parser-status p)
-       :full (yield (parser-produce p))
-       :error (onerr "parse" (parser-error p))
-       (select (fiber-status chars)
-        :new (parser-byte p (resume chars))
-        :pending (parser-byte p (resume chars))
-        (:= going false))))
-    (when (not= :root (parser-status p))
-     (onerr "parse" "unexpected end of source"))
-    nil)))
+ (def f (coro
+  (def p (parser 1)) 
+  (while going
+    (select (parser-status p)
+     :full (yield (parser-produce p))
+     :error (onerr "parse" (parser-error p))
+     (select (fiber-status chars)
+      :new (parser-byte p (resume chars))
+      :pending (parser-byte p (resume chars))
+      (:= going false))))
+  (when (not= :root (parser-status p))
+   (onerr "parse" "unexpected end of source"))
+  nil))
  (defn more [] (if temp true 
   (do 
    (:= temp true)
@@ -638,19 +643,22 @@ onvalue."
 (fn [env chunks onvalue onerr]
  (defn doone [source]
   (var good true)
-  (def f (fiber (fn []
+  (def f (coro
     (def res (compile source env))
     (if (= (type res) :function)
       (res)
       (do
        (:= good false)
-       (onerr "compile" (get res :error)))))))
+       (onerr "compile" (get res :error))))))
   (def res (resume f))
    (if good
     (if (= (fiber-status f) :error)
      (onerr "runtime" res f)
      (onvalue res))))
+ (def oldenv *env*)
+ (:= *env* env)
  (foreach (val-stream chunks onerr) doone)
+ (:= *env* oldenv)
  env)))
 
 (defn default-error-handler
@@ -689,11 +697,8 @@ onvalue."
      (put loading path true)
      (def f (file-open path))
      (defn chunks [buf] (file-read f 1024 buf))
-     (def oldenv *env*)
-     (:= *env* newenv)
      (run-context newenv chunks identity default-error-handler)
      (file-close f)
-     (:= *env* oldenv)
      (put loading path nil)
      newenv)))))