diff --git a/examples/3sum.dst b/examples/3sum.dst
index 0ab55d24..831c95a4 100644
--- a/examples/3sum.dst
+++ b/examples/3sum.dst
@@ -1,5 +1,4 @@
-
-(import "examples/iterators.dst")
+(import examples.iterators :as "")
 
 (defn sum3
  "Solve the 3SUM problem in O(n^2) time."
diff --git a/src/compiler/boot.dst b/src/compiler/boot.dst
index b1791e8d..6bd5bf66 100644
--- a/src/compiler/boot.dst
+++ b/src/compiler/boot.dst
@@ -66,6 +66,9 @@
   (def t (type x))
   (if (= t :integer) true (= t :real)))
 (defn fiber? [x] (= (type x) :fiber))
+(defn string? [x] (= (type x) :string))
+(defn symbol? [x] (= (type x) :symbol))
+(defn buffer? [x] (= (type x) :buffer))
 (defn function? [x] (= (type x) :function))
 (defn cfunction? [x] (= (type x) :cfunction))
 (defn abstract? [x] (= (type x) :abstract))
@@ -970,7 +973,29 @@ environment is needed, use run-context."
  (run-context *env* chunks (fn [x] (:= returnval x)) default-error-handler)
  returnval)
 
-(def require (do
+(def module.paths @[
+  "./?.dst"
+  "./?/init.dst"
+  "./dst_modules/?.dst"
+  "./dst_modules/?/init.dst"
+ ])
+
+(defn module.find
+  "Open a file given a module name."
+  [name]
+  (def normname (string.replace-all "." "/" name))
+  (defn checkmodule
+    [f testpath]
+    (if f f (do
+      (def p (string.replace-all "?" normname testpath))
+      (file.open p))))
+  (reduce checkmodule nil module.paths))
+
+(def require 
+ "Require a module with the given name. Will search all of the paths in
+module.paths, then the path as a raw file path. Returns the new environment
+returned from compiling and running the file."  
+ (do
  (def cache @{})
  (def loading @{})
  (fn [path]
@@ -986,7 +1011,9 @@ environment is needed, use run-context."
        (def newenv (make-env))
        (put cache path newenv)
        (put loading path true)
-       (def f (file.open path))
+       (def f (or (module.find path) (file.open path)))
+       (if (not f)
+         (error (string "could not open file for module " path)))
        (defn chunks [buf] (file.read f 1024 buf))
        (run-context newenv chunks identity default-error-handler)
        (file.close f)
@@ -996,10 +1023,12 @@ environment is needed, use run-context."
 (defn import* [env path & args]
  (def newenv (require path))
  (def {
+  :as as
   :prefix prefix
   } (apply1 table args))
  (var k (next newenv nil))
- (def prefix (if prefix prefix ""))
+ (def {:meta meta} newenv)
+ (def prefix (or (and as (string as ".")) prefix (string path ".")))
  (while k
   (def v (get newenv k))
   (when (not (get v :private))
@@ -1007,7 +1036,17 @@ environment is needed, use run-context."
   (:= k (next newenv k))))
 
 (defmacro import [path & args]
-  (apply tuple import* '_env path args))
+  "Import a module. First requires the module, and then merges its
+symbols into the current environment, prepending a given prefix as needed.
+(use the :as or :prefix option to set a prefix). If no prefix is provided,
+use the name of the module as a prefix."
+  (def upath (string (ast.unwrap path)))
+  (def argm (map (fn [x] 
+                    (if (and (symbol? x) (= (get x 0) 58))
+                      x
+                      (string x)))
+                     (ast.unwrap args)))
+  (apply tuple import* '_env upath argm))
 
 (defn repl [getchunk onvalue onerr]
   "Run a repl. The first parameter is an optional function to call to
diff --git a/src/core/gc.c b/src/core/gc.c
index 0759a457..03a77608 100644
--- a/src/core/gc.c
+++ b/src/core/gc.c
@@ -188,9 +188,7 @@ recur:
         return;
     dst_gc_mark(fiber);
 
-    /* Check if new fiber - all status bits sets indicate :new status */
-    if ((fiber->flags & DST_FIBER_STATUS_MASK) == DST_FIBER_STATUS_MASK) 
-        dst_mark_function(fiber->root);
+    dst_mark_function(fiber->root);
     
     i = fiber->frame;
     j = fiber->stackstart - DST_FRAME_SIZE;
diff --git a/src/core/io.c b/src/core/io.c
index 71b803cf..dfbbca2f 100644
--- a/src/core/io.c
+++ b/src/core/io.c
@@ -193,8 +193,7 @@ static int dst_io_fopen(DstArgs args) {
         DST_THROW(args, "invalid file mode");
     }
     f = fopen((const char *)fname, (const char *)fmode);
-    if (!f) DST_THROW(args, "could not open file");
-    DST_RETURN(args, makef(f, flags));
+    DST_RETURN(args, f ? makef(f, flags) : dst_wrap_nil());
 }
 
 /* Read a certain number of bytes into memory */
diff --git a/src/mainclient/init.dst b/src/mainclient/init.dst
index 369b3b66..30493e33 100644
--- a/src/mainclient/init.dst
+++ b/src/mainclient/init.dst
@@ -40,7 +40,7 @@
     (+= i (dohandler (string.slice arg 1 2) i))
     (do
       (:= *no-file* false)
-      (import arg)
+      (import* _env arg)
       (++ i))))
 
 (when (or *should-repl* *no-file*) 
diff --git a/test/suite0.dst b/test/suite0.dst
index f5f0ee48..5f7b7862 100644
--- a/test/suite0.dst
+++ b/test/suite0.dst
@@ -18,7 +18,7 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 # IN THE SOFTWARE.
 
-(import "test/helper.dst")
+(import test.helper :prefix "")
 (start-suite 0)
 
 (assert (= 10 (+ 1 2 3 4)) "addition")
diff --git a/test/suite1.dst b/test/suite1.dst
index 631d2118..09596c16 100644
--- a/test/suite1.dst
+++ b/test/suite1.dst
@@ -18,7 +18,7 @@
 # FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 # IN THE SOFTWARE.
 
-(import "test/helper.dst")
+(import test.helper :prefix "")
 (start-suite 1)
 
 (assert (= 400.0 (sqrt 160000)) "sqrt(160000)=400")