Merge branch 'master' of https://github.com/Araq/Nimrod

28 files changed, 1742 insertions, 342 deletions

diff --git a/lib/pure/algorithm.nim b/lib/pure/algorithm.nim
index 37fbc948c..86d329763 100644
--- a/lib/pure/algorithm.nim
+++ b/lib/pure/algorithm.nim
@@ -150,6 +150,15 @@ proc sort*[T](a: var openArray[T],
   ##    # overload:
   ##    sort(myStrArray, system.cmp)
   ##
+  ## You can inline adhoc comparison procs with the `do notation
+  ## <manual.html#do-notation>`_. Example:
+  ##
+  ## .. code-block:: nimrod
+  ##
+  ##   people.sort do (x, y: Person) -> int:
+  ##     result = cmp(x.surname, y.surname)
+  ##     if result == 0:
+  ##       result = cmp(x.name, y.name)
   var n = a.len
   var b: seq[T]
   newSeq(b, n div 2)
diff --git a/lib/pure/asyncdispatch.nim b/lib/pure/asyncdispatch.nim
index f50383038..d410f8ce1 100644
--- a/lib/pure/asyncdispatch.nim
+++ b/lib/pure/asyncdispatch.nim
@@ -11,8 +11,11 @@ include "system/inclrtl"
 
 import os, oids, tables, strutils, macros
 
-import rawsockets
-export TPort
+import rawsockets, net
+
+export TPort, TSocketFlags
+
+#{.injectStmt: newGcInvariant().}
 
 ## AsyncDispatch
 ## -------------
@@ -24,10 +27,12 @@ export TPort
 ## **Note:** This module is still largely experimental.
 
 
-# TODO: Discarded void PFutures need to checked for exception.
-# TODO: Exceptions are currently uncatchable due to the limitation that 
-# you cannot have yield in a try stmt. Perhaps I can get the macro to put
-# a user's try except around ``future.read``.
+# TODO: Discarded void PFutures need to be checked for exception.
+# TODO: ``except`` statement (without `try`) does not work.
+# TODO: Multiple exception names in a ``except`` don't work.
+# TODO: The effect system (raises: []) has trouble with my try transformation.
+# TODO: Can't await in a 'except' body
+# TODO: getCurrentException(Msg) don't work
 
 # -- Futures
 
@@ -35,19 +40,33 @@ type
   PFutureBase* = ref object of PObject
     cb: proc () {.closure,gcsafe.}
     finished: bool
+    error*: ref EBase
+    stackTrace: string ## For debugging purposes only.
 
   PFuture*[T] = ref object of PFutureBase
     value: T
-    error*: ref EBase # TODO: This shouldn't be necessary, generics bug?
 
 proc newFuture*[T](): PFuture[T] =
   ## Creates a new future.
   new(result)
   result.finished = false
+  result.stackTrace = getStackTrace()
+
+proc checkFinished[T](future: PFuture[T]) =
+  if future.finished:
+    echo("<----->")
+    echo(future.stackTrace)
+    echo("-----")
+    when T is string:
+      echo("Contents: ", future.value.repr)
+    echo("<----->")
+    echo("Future already finished, cannot finish twice.")
+    assert false
 
 proc complete*[T](future: PFuture[T], val: T) =
   ## Completes ``future`` with value ``val``.
-  assert(not future.finished, "Future already finished, cannot finish twice.")
+  #assert(not future.finished, "Future already finished, cannot finish twice.")
+  checkFinished(future)
   assert(future.error == nil)
   future.value = val
   future.finished = true
@@ -56,7 +75,8 @@ proc complete*[T](future: PFuture[T], val: T) =
 
 proc complete*(future: PFuture[void]) =
   ## Completes a void ``future``.
-  assert(not future.finished, "Future already finished, cannot finish twice.")
+  #assert(not future.finished, "Future already finished, cannot finish twice.")
+  checkFinished(future)
   assert(future.error == nil)
   future.finished = true
   if future.cb != nil:
@@ -64,11 +84,18 @@ proc complete*(future: PFuture[void]) =
 
 proc fail*[T](future: PFuture[T], error: ref EBase) =
   ## Completes ``future`` with ``error``.
-  assert(not future.finished, "Future already finished, cannot finish twice.")
+  #assert(not future.finished, "Future already finished, cannot finish twice.")
+  checkFinished(future)
   future.finished = true
   future.error = error
   if future.cb != nil:
     future.cb()
+  else:
+    # This is to prevent exceptions from being silently ignored when a future
+    # is discarded.
+    # TODO: This may turn out to be a bad idea.
+    # Turns out this is a bad idea.
+    #raise error
 
 proc `callback=`*(future: PFutureBase, cb: proc () {.closure,gcsafe.}) =
   ## Sets the callback proc to be called when the future completes.
@@ -112,10 +139,19 @@ proc finished*[T](future: PFuture[T]): bool =
   ## ``True`` may indicate an error or a value. Use ``failed`` to distinguish.
   future.finished
 
-proc failed*[T](future: PFuture[T]): bool =
+proc failed*(future: PFutureBase): bool =
   ## Determines whether ``future`` completed with an error.
   future.error != nil
 
+proc asyncCheck*[T](future: PFuture[T]) =
+  ## Sets a callback on ``future`` which raises an exception if the future
+  ## finished with an error.
+  ##
+  ## This should be used instead of ``discard`` to discard void futures.
+  future.callback =
+    proc () =
+      if future.failed: raise future.error
+
 when defined(windows) or defined(nimdoc):
   import winlean, sets, hashes
   type
@@ -130,15 +166,10 @@ when defined(windows) or defined(nimdoc):
       ioPort: THandle
       handles: TSet[TAsyncFD]
 
-    TCustomOverlapped = object
-      Internal*: DWORD
-      InternalHigh*: DWORD
-      Offset*: DWORD
-      OffsetHigh*: DWORD
-      hEvent*: THANDLE
+    TCustomOverlapped = object of TOVERLAPPED
       data*: TCompletionData
 
-    PCustomOverlapped = ptr TCustomOverlapped
+    PCustomOverlapped = ref TCustomOverlapped
 
     TAsyncFD* = distinct int
 
@@ -184,27 +215,27 @@ when defined(windows) or defined(nimdoc):
       else: timeout.int32
     var lpNumberOfBytesTransferred: DWORD
     var lpCompletionKey: ULONG
-    var lpOverlapped: POverlapped
-    let res = GetQueuedCompletionStatus(p.ioPort, addr lpNumberOfBytesTransferred,
-        addr lpCompletionKey, addr lpOverlapped, llTimeout).bool
+    var customOverlapped: PCustomOverlapped
+    let res = GetQueuedCompletionStatus(p.ioPort,
+        addr lpNumberOfBytesTransferred, addr lpCompletionKey,
+        cast[ptr POverlapped](addr customOverlapped), llTimeout).bool
 
     # http://stackoverflow.com/a/12277264/492186
     # TODO: http://www.serverframework.com/handling-multiple-pending-socket-read-and-write-operations.html
-    var customOverlapped = cast[PCustomOverlapped](lpOverlapped)
     if res:
       # This is useful for ensuring the reliability of the overlapped struct.
       assert customOverlapped.data.sock == lpCompletionKey.TAsyncFD
 
       customOverlapped.data.cb(customOverlapped.data.sock,
           lpNumberOfBytesTransferred, TOSErrorCode(-1))
-      dealloc(customOverlapped)
+      GC_unref(customOverlapped)
     else:
       let errCode = osLastError()
-      if lpOverlapped != nil:
+      if customOverlapped != nil:
         assert customOverlapped.data.sock == lpCompletionKey.TAsyncFD
         customOverlapped.data.cb(customOverlapped.data.sock,
             lpNumberOfBytesTransferred, errCode)
-        dealloc(customOverlapped)
+        GC_unref(customOverlapped)
       else:
         if errCode.int32 == WAIT_TIMEOUT:
           # Timed out
@@ -300,7 +331,8 @@ when defined(windows) or defined(nimdoc):
     while it != nil:
       # "the OVERLAPPED structure must remain valid until the I/O completes"
       # http://blogs.msdn.com/b/oldnewthing/archive/2011/02/02/10123392.aspx
-      var ol = cast[PCustomOverlapped](alloc0(sizeof(TCustomOverlapped)))
+      var ol = PCustomOverlapped()
+      GC_ref(ol)
       ol.data = TCompletionData(sock: socket, cb:
         proc (sock: TAsyncFD, bytesCount: DWord, errcode: TOSErrorCode) =
           if not retFuture.finished:
@@ -328,7 +360,7 @@ when defined(windows) or defined(nimdoc):
           success = true
           break
         else:
-          dealloc(ol)
+          GC_unref(ol)
           success = false
       it = it.ai_next
 
@@ -338,7 +370,7 @@ when defined(windows) or defined(nimdoc):
     return retFuture
 
   proc recv*(socket: TAsyncFD, size: int,
-             flags: int = 0): PFuture[string] =
+             flags = {TSocketFlags.SafeDisconn}): PFuture[string] =
     ## Reads **up to** ``size`` bytes from ``socket``. Returned future will
     ## complete once all the data requested is read, a part of the data has been
     ## read, or the socket has disconnected in which case the future will
@@ -352,15 +384,15 @@ when defined(windows) or defined(nimdoc):
     #     '\0' in the message currently signifies a socket disconnect. Who
     #     knows what will happen when someone sends that to our socket.
     verifyPresence(socket)
-    var retFuture = newFuture[string]()
-    
+    var retFuture = newFuture[string]()    
     var dataBuf: TWSABuf
     dataBuf.buf = cast[cstring](alloc0(size))
     dataBuf.len = size
     
     var bytesReceived: DWord
-    var flagsio = flags.DWord
-    var ol = cast[PCustomOverlapped](alloc0(sizeof(TCustomOverlapped)))
+    var flagsio = flags.toOSFlags().DWord
+    var ol = PCustomOverlapped()
+    GC_ref(ol)
     ol.data = TCompletionData(sock: socket, cb:
       proc (sock: TAsyncFD, bytesCount: DWord, errcode: TOSErrorCode) =
         if not retFuture.finished:
@@ -374,7 +406,9 @@ when defined(windows) or defined(nimdoc):
               retFuture.complete($data)
           else:
             retFuture.fail(newException(EOS, osErrorMsg(errcode)))
-        dealloc dataBuf.buf
+        if dataBuf.buf != nil:
+          dealloc dataBuf.buf
+          dataBuf.buf = nil
     )
 
     let ret = WSARecv(socket.TSocketHandle, addr dataBuf, 1, addr bytesReceived,
@@ -382,9 +416,14 @@ when defined(windows) or defined(nimdoc):
     if ret == -1:
       let err = osLastError()
       if err.int32 != ERROR_IO_PENDING:
-        dealloc dataBuf.buf
-        dealloc(ol)
-        retFuture.fail(newException(EOS, osErrorMsg(err)))
+        if dataBuf.buf != nil:
+          dealloc dataBuf.buf
+          dataBuf.buf = nil
+        GC_unref(ol)
+        if flags.isDisconnectionError(err):
+          retFuture.complete("")
+        else:
+          retFuture.fail(newException(EOS, osErrorMsg(err)))
     elif ret == 0 and bytesReceived == 0 and dataBuf.buf[0] == '\0':
       # We have to ensure that the buffer is empty because WSARecv will tell
       # us immediatelly when it was disconnected, even when there is still
@@ -415,7 +454,8 @@ when defined(windows) or defined(nimdoc):
       # free ``ol``.
     return retFuture
 
-  proc send*(socket: TAsyncFD, data: string): PFuture[void] =
+  proc send*(socket: TAsyncFD, data: string,
+             flags = {TSocketFlags.SafeDisconn}): PFuture[void] =
     ## Sends ``data`` to ``socket``. The returned future will complete once all
     ## data has been sent.
     verifyPresence(socket)
@@ -425,8 +465,9 @@ when defined(windows) or defined(nimdoc):
     dataBuf.buf = data # since this is not used in a callback, this is fine
     dataBuf.len = data.len
 
-    var bytesReceived, flags: DWord
-    var ol = cast[PCustomOverlapped](alloc0(sizeof(TCustomOverlapped)))
+    var bytesReceived, lowFlags: DWord
+    var ol = PCustomOverlapped()
+    GC_ref(ol)
     ol.data = TCompletionData(sock: socket, cb:
       proc (sock: TAsyncFD, bytesCount: DWord, errcode: TOSErrorCode) =
         if not retFuture.finished:
@@ -437,12 +478,15 @@ when defined(windows) or defined(nimdoc):
     )
 
     let ret = WSASend(socket.TSocketHandle, addr dataBuf, 1, addr bytesReceived,
-                      flags, cast[POverlapped](ol), nil)
+                      lowFlags, cast[POverlapped](ol), nil)
     if ret == -1:
       let err = osLastError()
       if err.int32 != ERROR_IO_PENDING:
-        retFuture.fail(newException(EOS, osErrorMsg(err)))
-        dealloc(ol)
+        GC_unref(ol)
+        if flags.isDisconnectionError(err):
+          retFuture.complete()
+        else:
+          retFuture.fail(newException(EOS, osErrorMsg(err)))
     else:
       retFuture.complete()
       # We don't deallocate ``ol`` here because even though this completed
@@ -490,7 +534,8 @@ when defined(windows) or defined(nimdoc):
          client: clientSock.TAsyncFD)
       )
 
-    var ol = cast[PCustomOverlapped](alloc0(sizeof(TCustomOverlapped)))
+    var ol = PCustomOverlapped()
+    GC_ref(ol)
     ol.data = TCompletionData(sock: socket, cb:
       proc (sock: TAsyncFD, bytesCount: DWord, errcode: TOSErrorCode) =
         if not retFuture.finished:
@@ -511,7 +556,7 @@ when defined(windows) or defined(nimdoc):
       let err = osLastError()
       if err.int32 != ERROR_IO_PENDING:
         retFuture.fail(newException(EOS, osErrorMsg(err)))
-        dealloc(ol)
+        GC_unref(ol)
     else:
       completeAccept()
       # We don't deallocate ``ol`` here because even though this completed
@@ -528,15 +573,30 @@ when defined(windows) or defined(nimdoc):
     result.TSocketHandle.setBlocking(false)
     register(result)
 
-  proc close*(socket: TAsyncFD) =
+  proc closeSocket*(socket: TAsyncFD) =
     ## Closes a socket and ensures that it is unregistered.
     socket.TSocketHandle.close()
     getGlobalDispatcher().handles.excl(socket)
 
+  proc unregister*(fd: TAsyncFD) =
+    ## Unregisters ``fd``.
+    getGlobalDispatcher().handles.excl(fd)
+
   initAll()
 else:
   import selectors
-  from posix import EINTR, EAGAIN, EINPROGRESS, EWOULDBLOCK, MSG_PEEK
+  when defined(windows):
+    import winlean
+    const
+      EINTR = WSAEINPROGRESS
+      EINPROGRESS = WSAEINPROGRESS
+      EWOULDBLOCK = WSAEWOULDBLOCK
+      EAGAIN = EINPROGRESS
+      MSG_NOSIGNAL = 0
+  else:
+    from posix import EINTR, EAGAIN, EINPROGRESS, EWOULDBLOCK, MSG_PEEK,
+                      MSG_NOSIGNAL
+  
   type
     TAsyncFD* = distinct cint
     TCallback = proc (sock: TAsyncFD): bool {.closure,gcsafe.}
@@ -577,11 +637,14 @@ else:
     result.TSocketHandle.setBlocking(false)
     register(result)
   
-  proc close*(sock: TAsyncFD) =
+  proc closeSocket*(sock: TAsyncFD) =
     let disp = getGlobalDispatcher()
     sock.TSocketHandle.close()
     disp.selector.unregister(sock.TSocketHandle)
 
+  proc unregister*(fd: TAsyncFD) =
+    getGlobalDispatcher().selector.unregister(fd.TSocketHandle)
+
   proc addRead(sock: TAsyncFD, cb: TCallback) =
     let p = getGlobalDispatcher()
     if sock.TSocketHandle notin p.selector:
@@ -667,20 +730,23 @@ else:
     return retFuture
 
   proc recv*(socket: TAsyncFD, size: int,
-             flags: int = 0): PFuture[string] =
+             flags = {TSocketFlags.SafeDisconn}): PFuture[string] =
     var retFuture = newFuture[string]()
     
     var readBuffer = newString(size)
 
     proc cb(sock: TAsyncFD): bool =
       result = true
-      let res = recv(sock.TSocketHandle, addr readBuffer[0], size,
-                     flags.cint)
+      let res = recv(sock.TSocketHandle, addr readBuffer[0], size.cint,
+                     flags.toOSFlags())
       #echo("recv cb res: ", res)
       if res < 0:
         let lastError = osLastError()
-        if lastError.int32 notin {EINTR, EWOULDBLOCK, EAGAIN}: 
-          retFuture.fail(newException(EOS, osErrorMsg(lastError)))
+        if lastError.int32 notin {EINTR, EWOULDBLOCK, EAGAIN}:
+          if flags.isDisconnectionError(lastError):
+            retFuture.complete("")
+          else:
+            retFuture.fail(newException(EOS, osErrorMsg(lastError)))
         else:
           result = false # We still want this callback to be called.
       elif res == 0:
@@ -689,11 +755,13 @@ else:
       else:
         readBuffer.setLen(res)
         retFuture.complete(readBuffer)
-  
+    # TODO: The following causes a massive slowdown.
+    #if not cb(socket):
     addRead(socket, cb)
     return retFuture
 
-  proc send*(socket: TAsyncFD, data: string): PFuture[void] =
+  proc send*(socket: TAsyncFD, data: string,
+             flags = {TSocketFlags.SafeDisconn}): PFuture[void] =
     var retFuture = newFuture[void]()
     
     var written = 0
@@ -702,11 +770,15 @@ else:
       result = true
       let netSize = data.len-written
       var d = data.cstring
-      let res = send(sock.TSocketHandle, addr d[written], netSize, 0.cint)
+      let res = send(sock.TSocketHandle, addr d[written], netSize.cint,
+                     MSG_NOSIGNAL)
       if res < 0:
         let lastError = osLastError()
         if lastError.int32 notin {EINTR, EWOULDBLOCK, EAGAIN}:
-          retFuture.fail(newException(EOS, osErrorMsg(lastError)))
+          if flags.isDisconnectionError(lastError):
+            retFuture.complete()
+          else:
+            retFuture.fail(newException(EOS, osErrorMsg(lastError)))
         else:
           result = false # We still want this callback to be called.
       else:
@@ -715,6 +787,8 @@ else:
           result = false # We still have data to send.
         else:
           retFuture.complete()
+    # TODO: The following causes crashes.
+    #if not cb(socket):
     addWrite(socket, cb)
     return retFuture
 
@@ -757,41 +831,76 @@ proc accept*(socket: TAsyncFD): PFuture[TAsyncFD] =
 
 # -- Await Macro
 
-template createCb*(retFutureSym, iteratorNameSym: expr): stmt {.immediate.} =
+template createCb*(retFutureSym, iteratorNameSym,
+                   name: expr): stmt {.immediate.} =
   var nameIterVar = iteratorNameSym
+  #{.push stackTrace: off.}
   proc cb {.closure,gcsafe.} =
-    if not nameIterVar.finished:
-      var next = nameIterVar()
-      if next == nil:
-        assert retFutureSym.finished, "Async procedure's return Future was not finished."
-      else:
-        next.callback = cb
+    try:
+      if not nameIterVar.finished:
+        var next = nameIterVar()
+        if next == nil:
+          assert retFutureSym.finished, "Async procedure's (" &
+                 name & ") return Future was not finished."
+        else:
+          next.callback = cb
+    except:
+      retFutureSym.fail(getCurrentException())
   cb()
-
-template createVar(futSymName: string, asyncProc: PNimrodNode,
-                   valueReceiver: expr) {.immediate, dirty.} =
-  # TODO: Used template here due to bug #926
+  #{.pop.}
+proc generateExceptionCheck(futSym,
+    exceptBranch, rootReceiver: PNimrodNode): PNimrodNode {.compileTime.} =
+  if exceptBranch == nil:
+    result = rootReceiver
+  else:
+    if exceptBranch[0].kind == nnkStmtList:
+      result = newIfStmt(
+        (newDotExpr(futSym, newIdentNode("failed")),
+           exceptBranch[0]
+         )
+      )
+    else:
+      expectKind(exceptBranch[1], nnkStmtList)
+      result = newIfStmt(
+        (newDotExpr(futSym, newIdentNode("failed")),
+           newIfStmt(
+             (infix(newDotExpr(futSym, newIdentNode("error")), "of", exceptBranch[0]),
+              exceptBranch[1])
+           )
+         )
+      )
+    let elseNode = newNimNode(nnkElse)
+    elseNode.add newNimNode(nnkStmtList)
+    elseNode[0].add rootReceiver
+    result.add elseNode
+
+template createVar(result: var PNimrodNode, futSymName: string,
+                   asyncProc: PNimrodNode,
+                   valueReceiver, rootReceiver: expr) =
   result = newNimNode(nnkStmtList)
   var futSym = genSym(nskVar, "future")
   result.add newVarStmt(futSym, asyncProc) # -> var future<x> = y
   result.add newNimNode(nnkYieldStmt).add(futSym) # -> yield future<x>
   valueReceiver = newDotExpr(futSym, newIdentNode("read")) # -> future<x>.read
+  result.add generateExceptionCheck(futSym, exceptBranch, rootReceiver)
 
 proc processBody(node, retFutureSym: PNimrodNode,
-                 subtypeName: string): PNimrodNode {.compileTime.} =
+                 subTypeIsVoid: bool,
+                 exceptBranch: PNimrodNode): PNimrodNode {.compileTime.} =
+  #echo(node.treeRepr)
   result = node
   case node.kind
   of nnkReturnStmt:
     result = newNimNode(nnkStmtList)
     if node[0].kind == nnkEmpty:
-      if subtypeName != "void":
+      if not subtypeIsVoid:
         result.add newCall(newIdentNode("complete"), retFutureSym,
             newIdentNode("result"))
       else:
         result.add newCall(newIdentNode("complete"), retFutureSym)
     else:
       result.add newCall(newIdentNode("complete"), retFutureSym,
-        node[0].processBody(retFutureSym, subtypeName))
+        node[0].processBody(retFutureSym, subtypeIsVoid, exceptBranch))
 
     result.add newNimNode(nnkReturnStmt).add(newNilLit())
     return # Don't process the children of this return stmt
@@ -804,16 +913,16 @@ proc processBody(node, retFutureSym: PNimrodNode,
       of nnkCall:
         # await foo(p, x)
         var futureValue: PNimrodNode
-        createVar("future" & $node[1][0].toStrLit, node[1], futureValue)
-        result.add futureValue
+        result.createVar("future" & $node[1][0].toStrLit, node[1], futureValue,
+                  futureValue)
       else:
         error("Invalid node kind in 'await', got: " & $node[1].kind)
     elif node[1].kind == nnkCommand and node[1][0].kind == nnkIdent and
          node[1][0].ident == !"await":
       # foo await x
       var newCommand = node
-      createVar("future" & $node[0].toStrLit, node[1][1], newCommand[1])
-      result.add newCommand
+      result.createVar("future" & $node[0].toStrLit, node[1][1], newCommand[1],
+                newCommand)
 
   of nnkVarSection, nnkLetSection:
     case node[0][2].kind
@@ -821,9 +930,8 @@ proc processBody(node, retFutureSym: PNimrodNode,
       if node[0][2][0].ident == !"await":
         # var x = await y
         var newVarSection = node # TODO: Should this use copyNimNode?
-        createVar("future" & $node[0][0].ident, node[0][2][1],
-          newVarSection[0][2])
-        result.add newVarSection
+        result.createVar("future" & $node[0][0].ident, node[0][2][1],
+          newVarSection[0][2], newVarSection)
     else: discard
   of nnkAsgn:
     case node[1].kind
@@ -831,19 +939,43 @@ proc processBody(node, retFutureSym: PNimrodNode,
       if node[1][0].ident == !"await":
         # x = await y
         var newAsgn = node
-        createVar("future" & $node[0].toStrLit, node[1][1], newAsgn[1])
-        result.add newAsgn
+        result.createVar("future" & $node[0].toStrLit, node[1][1], newAsgn[1], newAsgn)
     else: discard
   of nnkDiscardStmt:
     # discard await x
-    if node[0][0].kind == nnkIdent and node[0][0].ident == !"await":
-      var dummy = newNimNode(nnkStmtList)
-      createVar("futureDiscard_" & $toStrLit(node[0][1]), node[0][1], dummy)
+    if node[0].kind != nnkEmpty and node[0][0].kind == nnkIdent and
+          node[0][0].ident == !"await":
+      var newDiscard = node
+      result.createVar("futureDiscard_" & $toStrLit(node[0][1]), node[0][1],
+                newDiscard[0], newDiscard)
+  of nnkTryStmt:
+    # try: await x; except: ...
+    result = newNimNode(nnkStmtList)
+    proc processForTry(n: PNimrodNode, i: var int,
+                       res: PNimrodNode): bool {.compileTime.} =
+      result = false
+      while i < n[0].len:
+        var processed = processBody(n[0][i], retFutureSym, subtypeIsVoid, n[1])
+        if processed.kind != n[0][i].kind or processed.len != n[0][i].len:
+          expectKind(processed, nnkStmtList)
+          expectKind(processed[2][1], nnkElse)
+          i.inc
+          discard processForTry(n, i, processed[2][1][0])
+          res.add processed
+          result = true
+        else:
+          res.add n[0][i]
+          i.inc
+    var i = 0
+    if not processForTry(node, i, result):
+      var temp = node
+      temp[0] = result
+      result = temp
+    return
   else: discard
-  
+
   for i in 0 .. <result.len:
-    result[i] = processBody(result[i], retFutureSym, subtypeName)
-  #echo(treeRepr(result))
+    result[i] = processBody(result[i], retFutureSym, subtypeIsVoid, exceptBranch)
 
 proc getName(node: PNimrodNode): string {.compileTime.} =
   case node.kind
@@ -851,47 +983,53 @@ proc getName(node: PNimrodNode): string {.compileTime.} =
     return $node[1].ident
   of nnkIdent:
     return $node.ident
+  of nnkEmpty:
+    return "anonymous"
   else:
-    assert false
+    error("Unknown name.")
 
 macro async*(prc: stmt): stmt {.immediate.} =
   ## Macro which processes async procedures into the appropriate
   ## iterators and yield statements.
-
-  expectKind(prc, nnkProcDef)
+  if prc.kind notin {nnkProcDef, nnkLambda}:
+    error("Cannot transform this node kind into an async proc." &
+          " Proc definition or lambda node expected.")
 
   hint("Processing " & prc[0].getName & " as an async proc.")
 
   let returnType = prc[3][0]
-  var subtypeName = ""
   # Verify that the return type is a PFuture[T]
   if returnType.kind == nnkIdent:
     error("Expected return type of 'PFuture' got '" & $returnType & "'")
   elif returnType.kind == nnkBracketExpr:
     if $returnType[0] != "PFuture":
       error("Expected return type of 'PFuture' got '" & $returnType[0] & "'")
-    subtypeName = $returnType[1].ident
-  elif returnType.kind == nnkEmpty:
-    subtypeName = "void"
+
+  let subtypeIsVoid = returnType.kind == nnkEmpty or
+        (returnType.kind == nnkBracketExpr and
+         returnType[1].kind == nnkIdent and returnType[1].ident == !"void")
 
   var outerProcBody = newNimNode(nnkStmtList)
 
   # -> var retFuture = newFuture[T]()
   var retFutureSym = genSym(nskVar, "retFuture")
+  var subRetType =
+    if returnType.kind == nnkEmpty: newIdentNode("void")
+    else: returnType[1]
   outerProcBody.add(
     newVarStmt(retFutureSym, 
       newCall(
         newNimNode(nnkBracketExpr).add(
           newIdentNode(!"newFuture"), # TODO: Strange bug here? Remove the `!`.
-          newIdentNode(subtypeName))))) # Get type from return type of this proc
+          subRetType)))) # Get type from return type of this proc
   
   # -> iterator nameIter(): PFutureBase {.closure.} = 
   # ->   var result: T
   # ->   <proc_body>
   # ->   complete(retFuture, result)
   var iteratorNameSym = genSym(nskIterator, $prc[0].getName & "Iter")
-  var procBody = prc[6].processBody(retFutureSym, subtypeName)
-  if subtypeName != "void":
+  var procBody = prc[6].processBody(retFutureSym, subtypeIsVoid, nil)
+  if not subtypeIsVoid:
     procBody.insert(0, newNimNode(nnkVarSection).add(
       newIdentDefs(newIdentNode("result"), returnType[1]))) # -> var result: T
     procBody.add(
@@ -908,7 +1046,8 @@ macro async*(prc: stmt): stmt {.immediate.} =
 
   # -> createCb(retFuture)
   var cbName = newIdentNode("cb")
-  var procCb = newCall("createCb", retFutureSym, iteratorNameSym)
+  var procCb = newCall("createCb", retFutureSym, iteratorNameSym,
+                       newStrLitNode(prc[0].getName))
   outerProcBody.add procCb
 
   # -> return retFuture
@@ -918,17 +1057,18 @@ macro async*(prc: stmt): stmt {.immediate.} =
 
   # Remove the 'async' pragma.
   for i in 0 .. <result[4].len:
-    if result[4][i].ident == !"async":
+    if result[4][i].kind == nnkIdent and result[4][i].ident == !"async":
       result[4].del(i)
-  if subtypeName == "void":
+  if subtypeIsVoid:
     # Add discardable pragma.
-    result[4].add(newIdentNode("discardable"))
     if returnType.kind == nnkEmpty:
       # Add PFuture[void]
       result[3][0] = parseExpr("PFuture[void]")
 
   result[6] = outerProcBody
 
+  #echo(treeRepr(result))
+  #if prc[0].getName == "routeReq":
   #echo(toStrLit(result))
 
 proc recvLine*(socket: TAsyncFD): PFuture[string] {.async.} =
@@ -956,7 +1096,7 @@ proc recvLine*(socket: TAsyncFD): PFuture[string] {.async.} =
     if c.len == 0:
       return ""
     if c == "\r":
-      c = await recv(socket, 1, MSG_PEEK)
+      c = await recv(socket, 1, {TSocketFlags.SafeDisconn, TSocketFlags.Peek})
       if c.len > 0 and c == "\L":
         discard await recv(socket, 1)
       addNLIfEmpty()
diff --git a/lib/pure/asynchttpserver.nim b/lib/pure/asynchttpserver.nim
index 2ebd7036d..ee6658fd1 100644
--- a/lib/pure/asynchttpserver.nim
+++ b/lib/pure/asynchttpserver.nim
@@ -14,12 +14,13 @@
 import strtabs, asyncnet, asyncdispatch, parseutils, parseurl, strutils
 type
   TRequest* = object
-    client: PAsyncSocket # TODO: Separate this into a Response object?
+    client*: PAsyncSocket # TODO: Separate this into a Response object?
     reqMethod*: string
     headers*: PStringTable
     protocol*: tuple[orig: string, major, minor: int]
     url*: TURL
     hostname*: string ## The hostname of the client that made the request.
+    body*: string
 
   PAsyncHttpServer* = ref object
     socket: PAsyncSocket
@@ -50,10 +51,15 @@ proc `==`*(protocol: tuple[orig: string, major, minor: int],
 proc newAsyncHttpServer*(): PAsyncHttpServer =
   new result
 
-proc sendHeaders*(req: TRequest, headers: PStringTable) {.async.} =
-  ## Sends the specified headers to the requesting client.
+proc addHeaders(msg: var string, headers: PStringTable) =
   for k, v in headers:
-    await req.client.send(k & ": " & v & "\c\L")
+    msg.add(k & ": " & v & "\c\L")
+
+proc sendHeaders*(req: TRequest, headers: PStringTable): PFuture[void] =
+  ## Sends the specified headers to the requesting client.
+  var msg = ""
+  addHeaders(msg, headers)
+  return req.client.send(msg)
 
 proc respond*(req: TRequest, code: THttpCode,
         content: string, headers: PStringTable = newStringTable()) {.async.} =
@@ -63,9 +69,9 @@ proc respond*(req: TRequest, code: THttpCode,
   ## This procedure will **not** close the client socket.
   var customHeaders = headers
   customHeaders["Content-Length"] = $content.len
-  await req.client.send("HTTP/1.1 " & $code & "\c\L")
-  await sendHeaders(req, headers)
-  await req.client.send("\c\L" & content)
+  var msg = "HTTP/1.1 " & $code & "\c\L"
+  msg.addHeaders(customHeaders)
+  await req.client.send(msg & "\c\L" & content)
 
 proc newRequest(): TRequest =
   result.headers = newStringTable(modeCaseInsensitive)
@@ -77,7 +83,7 @@ proc parseHeader(line: string): tuple[key, value: string] =
   i += line.skipWhiteSpace(i)
   i += line.parseUntil(result.value, {'\c', '\L'}, i)
 
-proc parseProtocol(protocol: string):  tuple[orig: string, major, minor: int] =
+proc parseProtocol(protocol: string): tuple[orig: string, major, minor: int] =
   var i = protocol.skipIgnoreCase("HTTP/")
   if i != 5:
     raise newException(EInvalidValue, "Invalid request protocol. Got: " &
@@ -87,70 +93,95 @@ proc parseProtocol(protocol: string):  tuple[orig: string, major, minor: int] =
   i.inc # Skip .
   i.inc protocol.parseInt(result.minor, i)
 
+proc sendStatus(client: PAsyncSocket, status: string): PFuture[void] =
+  client.send("HTTP/1.1 " & status & "\c\L")
+
 proc processClient(client: PAsyncSocket, address: string,
                  callback: proc (request: TRequest): PFuture[void]) {.async.} =
-  # GET /path HTTP/1.1
-  # Header: val
-  # \n
-  var request = newRequest()
-  request.hostname = address
-  assert client != nil
-  request.client = client
-
-  # First line - GET /path HTTP/1.1
-  let line = await client.recvLine() # TODO: Timeouts.
-  if line == "":
-    client.close()
-    return
-  let lineParts = line.split(' ')
-  if lineParts.len != 3:
-    request.respond(Http400, "Invalid request. Got: " & line)
-    client.close()
-    return
-
-  let reqMethod = lineParts[0]
-  let path = lineParts[1]
-  let protocol = lineParts[2]
-
-  # Headers
-  var i = 0
   while true:
-    i = 0
-    let headerLine = await client.recvLine()
-    if headerLine == "":
-      client.close(); return
-    if headerLine == "\c\L": break
-    # TODO: Compiler crash
-    #let (key, value) = parseHeader(headerLine)
-    let kv = parseHeader(headerLine)
-    request.headers[kv.key] = kv.value
-
-  request.reqMethod = reqMethod
-  request.url = parseUrl(path)
-  try:
-    request.protocol = protocol.parseProtocol()
-  except EInvalidValue:
-    request.respond(Http400, "Invalid request protocol. Got: " & protocol)
-    return
-  
-  case reqMethod.normalize
-  of "get", "post", "head", "put", "delete", "trace", "options", "connect", "patch":
-    await callback(request)
-  else:
-    request.respond(Http400, "Invalid request method. Got: " & reqMethod)
-
-  # Persistent connections
-  if (request.protocol == HttpVer11 and
-      request.headers["connection"].normalize != "close") or
-     (request.protocol == HttpVer10 and
-      request.headers["connection"].normalize == "keep-alive"):
-    # In HTTP 1.1 we assume that connection is persistent. Unless connection
-    # header states otherwise.
-    # In HTTP 1.0 we assume that the connection should not be persistent.
-    # Unless the connection header states otherwise.
-    await processClient(client, address, callback)
-  else:
-    request.client.close()
+    # GET /path HTTP/1.1
+    # Header: val
+    # \n
+    var request = newRequest()
+    request.hostname = address
+    assert client != nil
+    request.client = client
+
+    # First line - GET /path HTTP/1.1
+    let line = await client.recvLine() # TODO: Timeouts.
+    if line == "":
+      client.close()
+      return
+    let lineParts = line.split(' ')
+    if lineParts.len != 3:
+      await request.respond(Http400, "Invalid request. Got: " & line)
+      continue
+
+    let reqMethod = lineParts[0]
+    let path = lineParts[1]
+    let protocol = lineParts[2]
+
+    # Headers
+    var i = 0
+    while true:
+      i = 0
+      let headerLine = await client.recvLine()
+      if headerLine == "":
+        client.close(); return
+      if headerLine == "\c\L": break
+      # TODO: Compiler crash
+      #let (key, value) = parseHeader(headerLine)
+      let kv = parseHeader(headerLine)
+      request.headers[kv.key] = kv.value
+
+    request.reqMethod = reqMethod
+    request.url = parseUrl(path)
+    try:
+      request.protocol = protocol.parseProtocol()
+    except EInvalidValue:
+      asyncCheck request.respond(Http400, "Invalid request protocol. Got: " &
+          protocol)
+      continue
+
+    if reqMethod.normalize == "post":
+      # Check for Expect header
+      if request.headers.hasKey("Expect"):
+        if request.headers["Expect"].toLower == "100-continue":
+          await client.sendStatus("100 Continue")
+        else:
+          await client.sendStatus("417 Expectation Failed")
+    
+      # Read the body
+      # - Check for Content-length header
+      if request.headers.hasKey("Content-Length"):
+        var contentLength = 0
+        if parseInt(request.headers["Content-Length"], contentLength) == 0:
+          await request.respond(Http400, "Bad Request. Invalid Content-Length.")
+        else:
+          request.body = await client.recv(contentLength)
+          assert request.body.len == contentLength
+      else:
+        await request.respond(Http400, "Bad Request. No Content-Length.")
+        continue
+
+    case reqMethod.normalize
+    of "get", "post", "head", "put", "delete", "trace", "options", "connect", "patch":
+      await callback(request)
+    else:
+      await request.respond(Http400, "Invalid request method. Got: " & reqMethod)
+
+    # Persistent connections
+    if (request.protocol == HttpVer11 and
+        request.headers["connection"].normalize != "close") or
+       (request.protocol == HttpVer10 and
+        request.headers["connection"].normalize == "keep-alive"):
+      # In HTTP 1.1 we assume that connection is persistent. Unless connection
+      # header states otherwise.
+      # In HTTP 1.0 we assume that the connection should not be persistent.
+      # Unless the connection header states otherwise.
+    else:
+      request.client.close()
+      break
 
 proc serve*(server: PAsyncHttpServer, port: TPort,
             callback: proc (request: TRequest): PFuture[void],
@@ -167,14 +198,20 @@ proc serve*(server: PAsyncHttpServer, port: TPort,
     # TODO: Causes compiler crash.
     #var (address, client) = await server.socket.acceptAddr()
     var fut = await server.socket.acceptAddr()
-    processClient(fut.client, fut.address, callback)
+    asyncCheck processClient(fut.client, fut.address, callback)
+
+proc close*(server: PAsyncHttpServer) =
+  ## Terminates the async http server instance.
+  server.socket.close()
 
 when isMainModule:
   var server = newAsyncHttpServer()
   proc cb(req: TRequest) {.async.} =
     #echo(req.reqMethod, " ", req.url)
     #echo(req.headers)
-    await req.respond(Http200, "Hello World")
+    let headers = {"Date": "Tue, 29 Apr 2014 23:40:08 GMT",
+        "Content-type": "text/plain; charset=utf-8"}
+    await req.respond(Http200, "Hello World", headers.newStringTable())
 
-  server.serve(TPort(5555), cb)
+  asyncCheck server.serve(TPort(5555), cb)
   runForever()
diff --git a/lib/pure/asyncnet.nim b/lib/pure/asyncnet.nim
index b1abf627b..374ac77e3 100644
--- a/lib/pure/asyncnet.nim
+++ b/lib/pure/asyncnet.nim
@@ -80,7 +80,8 @@ proc connect*(socket: PAsyncSocket, address: string, port: TPort,
   ## or an error occurs.
   result = connect(socket.fd.TAsyncFD, address, port, af)
 
-proc readIntoBuf(socket: PAsyncSocket, flags: int): PFuture[int] {.async.} =
+proc readIntoBuf(socket: PAsyncSocket,
+    flags: set[TSocketFlags]): PFuture[int] {.async.} =
   var data = await recv(socket.fd.TAsyncFD, BufferSize, flags)
   if data.len != 0:
     copyMem(addr socket.buffer[0], addr data[0], data.len)
@@ -89,7 +90,7 @@ proc readIntoBuf(socket: PAsyncSocket, flags: int): PFuture[int] {.async.} =
   result = data.len
 
 proc recv*(socket: PAsyncSocket, size: int,
-           flags: int = 0): PFuture[string] {.async.} =
+           flags = {TSocketFlags.SafeDisconn}): PFuture[string] {.async.} =
   ## Reads ``size`` bytes from ``socket``. Returned future will complete once
   ## all of the requested data is read. If socket is disconnected during the
   ## recv operation then the future may complete with only a part of the
@@ -97,37 +98,42 @@ proc recv*(socket: PAsyncSocket, size: int,
   ## to be read then the future will complete with a value of ``""``.
   if socket.isBuffered:
     result = newString(size)
-
-    template returnNow(readBytes: int) =
-      result.setLen(readBytes)
-      # Only increase buffer position when not peeking.
-      if (flags and MSG_PEEK) != MSG_PEEK:
-        socket.currPos.inc(readBytes)
-      return
+    let originalBufPos = socket.currPos
 
     if socket.bufLen == 0:
-      let res = await socket.readIntoBuf(flags and (not MSG_PEEK))
-      if res == 0: returnNow(0)
+      let res = await socket.readIntoBuf(flags - {TSocketFlags.Peek})
+      if res == 0:
+        result.setLen(0)
+        return
 
     var read = 0
     while read < size:
       if socket.currPos >= socket.bufLen:
-        let res = await socket.readIntoBuf(flags and (not MSG_PEEK))
-        if res == 0: returnNow(read)
+        if TSocketFlags.Peek in flags:
+          # We don't want to get another buffer if we're peeking.
+          break
+        let res = await socket.readIntoBuf(flags - {TSocketFlags.Peek})
+        if res == 0:
+          break
 
       let chunk = min(socket.bufLen-socket.currPos, size-read)
-      copyMem(addr(result[read]), addr(socket.buffer[socket.currPos+read]), chunk)
+      copyMem(addr(result[read]), addr(socket.buffer[socket.currPos]), chunk)
       read.inc(chunk)
+      socket.currPos.inc(chunk)
 
-    returnNow(read)
+    if TSocketFlags.Peek in flags:
+      # Restore old buffer cursor position.
+      socket.currPos = originalBufPos
+    result.setLen(read)
   else:
     result = await recv(socket.fd.TAsyncFD, size, flags)
 
-proc send*(socket: PAsyncSocket, data: string): PFuture[void] =
+proc send*(socket: PAsyncSocket, data: string,
+           flags = {TSocketFlags.SafeDisconn}): PFuture[void] =
   ## Sends ``data`` to ``socket``. The returned future will complete once all
   ## data has been sent.
   assert socket != nil
-  result = send(socket.fd.TAsyncFD, data)
+  result = send(socket.fd.TAsyncFD, data, flags)
 
 proc acceptAddr*(socket: PAsyncSocket): 
       PFuture[tuple[address: string, client: PAsyncSocket]] =
@@ -162,7 +168,8 @@ proc accept*(socket: PAsyncSocket): PFuture[PAsyncSocket] =
         retFut.complete(future.read.client)
   return retFut
 
-proc recvLine*(socket: PAsyncSocket): PFuture[string] {.async.} =
+proc recvLine*(socket: PAsyncSocket,
+    flags = {TSocketFlags.SafeDisconn}): PFuture[string] {.async.} =
   ## Reads a line of data from ``socket``. Returned future will complete once
   ## a full line is read or an error occurs.
   ##
@@ -175,28 +182,60 @@ proc recvLine*(socket: PAsyncSocket): PFuture[string] {.async.} =
   ## If the socket is disconnected in the middle of a line (before ``\r\L``
   ## is read) then line will be set to ``""``.
   ## The partial line **will be lost**.
-  
+  ##
+  ## **Warning**: The ``Peek`` flag is not yet implemented.
   template addNLIfEmpty(): stmt =
     if result.len == 0:
       result.add("\c\L")
+  assert TSocketFlags.Peek notin flags ## TODO:
+  if socket.isBuffered:
+    result = ""
+    if socket.bufLen == 0:
+      let res = await socket.readIntoBuf(flags)
+      if res == 0:
+        return
 
-  result = ""
-  var c = ""
-  while true:
-    c = await recv(socket, 1)
-    if c.len == 0:
-      return ""
-    if c == "\r":
-      c = await recv(socket, 1, MSG_PEEK)
-      if c.len > 0 and c == "\L":
-        let dummy = await recv(socket, 1)
-        assert dummy == "\L"
-      addNLIfEmpty()
-      return
-    elif c == "\L":
-      addNLIfEmpty()
-      return
-    add(result.string, c)
+    var lastR = false
+    while true:
+      if socket.currPos >= socket.bufLen:
+        let res = await socket.readIntoBuf(flags)
+        if res == 0:
+          result = ""
+          break
+
+      case socket.buffer[socket.currPos]
+      of '\r':
+        lastR = true
+        addNLIfEmpty()
+      of '\L':
+        addNLIfEmpty()
+        socket.currPos.inc()
+        return
+      else:
+        if lastR:
+          socket.currPos.inc()
+          return
+        else:
+          result.add socket.buffer[socket.currPos]
+      socket.currPos.inc()
+  else:
+    result = ""
+    var c = ""
+    while true:
+      c = await recv(socket, 1, flags)
+      if c.len == 0:
+        return ""
+      if c == "\r":
+        c = await recv(socket, 1, flags + {TSocketFlags.Peek})
+        if c.len > 0 and c == "\L":
+          let dummy = await recv(socket, 1, flags)
+          assert dummy == "\L"
+        addNLIfEmpty()
+        return
+      elif c == "\L":
+        addNLIfEmpty()
+        return
+      add(result.string, c)
 
 proc bindAddr*(socket: PAsyncSocket, port = TPort(0), address = "") =
   ## Binds ``address``:``port`` to the socket.
@@ -214,7 +253,7 @@ proc listen*(socket: PAsyncSocket, backlog = SOMAXCONN) =
 
 proc close*(socket: PAsyncSocket) =
   ## Closes the socket.
-  socket.fd.TAsyncFD.close()
+  socket.fd.TAsyncFD.closeSocket()
   # TODO SSL
 
 when isMainModule:
@@ -235,7 +274,7 @@ when isMainModule:
           break
         else:
           echo("Got line: ", line)
-    main()
+    asyncCheck main()
   elif test == LowClient:
     var sock = newAsyncSocket()
     var f = connect(sock, "irc.freenode.net", TPort(6667))
diff --git a/lib/pure/collections/sequtils.nim b/lib/pure/collections/sequtils.nim
index f5db9d3fa..e760c5e02 100644
--- a/lib/pure/collections/sequtils.nim
+++ b/lib/pure/collections/sequtils.nim
@@ -47,19 +47,15 @@ proc concat*[T](seqs: varargs[seq[T]]): seq[T] =
       result[i] = itm
       inc(i)
 
-proc distnct*[T](seq1: seq[T]): seq[T] =
+proc deduplicate*[T](seq1: seq[T]): seq[T] =
   ## Returns a new sequence without duplicates.
   ##
-  ## This proc is `misspelled` on purpose to avoid a clash with the keyword
-  ## ``distinct`` used to `define a derived type incompatible with its base
-  ## type <manual.html#distinct-type>`_. Example:
-  ##
   ## .. code-block:: nimrod
   ##   let
   ##     dup1 = @[1, 1, 3, 4, 2, 2, 8, 1, 4]
   ##     dup2 = @["a", "a", "c", "d", "d"]
-  ##     unique1 = distnct(dup1)
-  ##     unique2 = distnct(dup2)
+  ##     unique1 = deduplicate(dup1)
+  ##     unique2 = deduplicate(dup2)
   ##   assert unique1 == @[1, 3, 4, 2, 8]
   ##   assert unique2 == @["a", "c", "d"]
   result = @[]
@@ -182,6 +178,24 @@ proc filter*[T](seq1: seq[T], pred: proc(item: T): bool {.closure.}): seq[T] =
   ##   assert f2 == @["yellow"]
   accumulateResult(filter(seq1, pred))
 
+proc keepIf*[T](seq1: var seq[T], pred: proc(item: T): bool {.closure.}) =
+  ## Keeps the items in the passed sequence if they fulfilled the predicate.
+  ## Same as the ``filter`` proc, but modifies the sequence directly.
+  ##
+  ## Example:
+  ##
+  ## .. code-block:: nimrod
+  ##   var floats = @[13.0, 12.5, 5.8, 2.0, 6.1, 9.9, 10.1]
+  ##   filter(floats, proc(x: float): bool = x > 10)
+  ##   assert floats == @[13.0, 12.5, 10.1]
+  var pos = 0
+  for i in 0 .. <len(seq1):
+    if pred(seq1[i]):
+      if pos != i:
+        seq1[pos] = seq1[i]
+      inc(pos)
+  setLen(seq1, pos)
+
 proc delete*[T](s: var seq[T], first=0, last=0) =
   ## Deletes in `s` the items at position `first` .. `last`. This modifies
   ## `s` itself, it does not return a copy.
@@ -252,6 +266,27 @@ template filterIt*(seq1, pred: expr): expr {.immediate.} =
     if pred: result.add(it)
   result
 
+template keepItIf*(varSeq, pred: expr) =
+  ## Convenience template around the ``keepIf`` proc to reduce typing.
+  ##
+  ## Unlike the `proc` version, the predicate needs to be an expression using
+  ## the ``it`` variable for testing, like: ``keepItIf("abcxyz", it == 'x')``.
+  ## Example:
+  ##
+  ## .. code-block:: nimrod
+  ##   var candidates = @["foo", "bar", "baz", "foobar"]
+  ##   keepItIf(candidates, it.len == 3 and it[0] == 'b')
+  ##   assert candidates == @["bar", "baz"]
+  var pos = 0
+  for i in 0 .. <len(varSeq):
+    let it {.inject.} = varSeq[i]
+    if pred:
+      if pos != i:
+        varSeq[pos] = varSeq[i]
+      inc(pos)
+  setLen(varSeq, pos)
+
+
 template toSeq*(iter: expr): expr {.immediate.} =
   ## Transforms any iterator into a sequence.
   ##
@@ -387,8 +422,8 @@ when isMainModule:
     let
       dup1 = @[1, 1, 3, 4, 2, 2, 8, 1, 4]
       dup2 = @["a", "a", "c", "d", "d"]
-      unique1 = distnct(dup1)
-      unique2 = distnct(dup2)
+      unique1 = deduplicate(dup1)
+      unique2 = deduplicate(dup2)
     assert unique1 == @[1, 3, 4, 2, 8]
     assert unique2 == @["a", "c", "d"]
 
@@ -418,6 +453,11 @@ when isMainModule:
       echo($n)
     # echoes 4, 8, 4 in separate lines
 
+  block: # keepIf test
+    var floats = @[13.0, 12.5, 5.8, 2.0, 6.1, 9.9, 10.1]
+    keepIf(floats, proc(x: float): bool = x > 10)
+    assert floats == @[13.0, 12.5, 10.1]
+
   block: # filterIt test
     let
       temperatures = @[-272.15, -2.0, 24.5, 44.31, 99.9, -113.44]
@@ -426,6 +466,11 @@ when isMainModule:
     assert acceptable == @[-2.0, 24.5, 44.31]
     assert notAcceptable == @[-272.15, 99.9, -113.44]
 
+  block: # keepItIf test
+    var candidates = @["foo", "bar", "baz", "foobar"]
+    keepItIf(candidates, it.len == 3 and it[0] == 'b')
+    assert candidates == @["bar", "baz"]
+
   block: # toSeq test
     let
       numeric = @[1, 2, 3, 4, 5, 6, 7, 8, 9]
diff --git a/lib/pure/collections/sets.nim b/lib/pure/collections/sets.nim
index bc249ed63..4ba67cb2e 100644
--- a/lib/pure/collections/sets.nim
+++ b/lib/pure/collections/sets.nim
@@ -112,6 +112,10 @@ proc incl*[A](s: var TSet[A], key: A) =
   ## includes an element `key` in `s`.
   inclImpl()
 
+proc incl*[A](s: var TSet[A], other: TSet[A]) =
+  ## includes everything in `other` in `s`
+  for item in other: incl(s, item)
+
 proc excl*[A](s: var TSet[A], key: A) =
   ## excludes `key` from the set `s`.
   var index = rawGet(s, key)
@@ -119,6 +123,10 @@ proc excl*[A](s: var TSet[A], key: A) =
     s.data[index].slot = seDeleted
     dec(s.counter)
 
+proc excl*[A](s: var TSet[A], other: TSet[A]) =
+  ## excludes everything in `other` from `s`.
+  for item in other: excl(s, item)
+
 proc containsOrIncl*[A](s: var TSet[A], key: A): bool =
   ## returns true if `s` contains `key`, otherwise `key` is included in `s`
   ## and false is returned.
@@ -147,6 +155,43 @@ proc `$`*[A](s: TSet[A]): string =
   ## The `$` operator for hash sets.
   dollarImpl()
 
+proc union*[A](s1, s2: TSet[A]): TSet[A] =
+  ## returns a new set of all items that are contained in at
+  ## least one of `s1` and `s2`
+  result = s1
+  incl(result, s2)
+
+proc intersection*[A](s1, s2: TSet[A]): TSet[A] =
+  ## returns a new set of all items that are contained in both `s1` and `s2`
+  result = initSet[A](min(s1.data.len, s2.data.len))
+  for item in s1:
+    if item in s2: incl(result, item)
+
+proc symmetricDifference*[A](s1, s2: TSet[A]): TSet[A] =
+  ## returns a new set of all items that are contained in either
+  ## `s1` or `s2`, but not both
+  result = s1
+  for item in s2:
+    if containsOrIncl(result, item): excl(result, item)
+
+proc `+`*[A](s1, s2: TSet[A]): TSet[A] {.inline.} =
+  ## alias for `union`
+  result = union(s1, s2)
+
+proc `*`*[A](s1, s2: TSet[A]): TSet[A] {.inline.} =
+  ## alias for `intersection`
+  result = intersection(s1, s2)
+
+proc `-+-`*[A](s1, s2: TSet[A]): TSet[A] {.inline.} =
+  ## alias for `symmetricDifference`
+  result = symmetricDifference(s1, s2)
+
+proc disjoint*[A](s1, s2: TSet[A]): bool =
+  ## returns true iff `s1` and `s2` have no items in common
+  for item in s1:
+    if item in s2: return false
+  return true
+
 # ------------------------------ ordered set ------------------------------
 
 type
@@ -211,6 +256,10 @@ proc incl*[A](s: var TOrderedSet[A], key: A) =
   ## includes an element `key` in `s`.
   inclImpl()
 
+proc incl*[A](s: var TSet[A], other: TOrderedSet[A]) =
+  ## includes everything in `other` in `s`
+  for item in other: incl(s, item)
+
 proc containsOrIncl*[A](s: var TOrderedSet[A], key: A): bool =
   ## returns true if `s` contains `key`, otherwise `key` is included in `s`
   ## and false is returned.
diff --git a/lib/pure/collections/tables.nim b/lib/pure/collections/tables.nim
index cd28f9af0..ce9df09e1 100644
--- a/lib/pure/collections/tables.nim
+++ b/lib/pure/collections/tables.nim
@@ -10,6 +10,48 @@
 ## The ``tables`` module implements an efficient hash table that is
 ## a mapping from keys to values.
 ##
+## If you are using simple standard types like ``int`` or ``string`` for the
+## keys of the table you won't have any problems, but as soon as you try to use
+## a more complex object as a key you will be greeted by a strange compiler
+## error::
+##
+##   Error: type mismatch: got (Person)
+##   but expected one of:
+##   hashes.hash(x: openarray[A]): THash
+##   hashes.hash(x: int): THash
+##   hashes.hash(x: float): THash
+##   …
+##
+## What is happening here is that the types used for table keys require to have
+## a ``hash()`` proc which will convert them to a `THash <hashes.html#THash>`_
+## value, and the compiler is listing all the hash functions it knows. After
+## you add such a proc for your custom type everything will work. See this
+## example:
+##
+## .. code-block:: nimrod
+##   type
+##     Person = object
+##       firstName, lastName: string
+##
+##   proc hash(x: Person): THash =
+##     ## Piggyback on the already available string hash proc.
+##     ##
+##     ## Without this proc nothing works!
+##     result = x.firstName.hash !& x.lastName.hash
+##     result = !$result
+##
+##   var
+##     salaries = initTable[Person, int]()
+##     p1, p2: Person
+##
+##   p1.firstName = "Jon"
+##   p1.lastName = "Ross"
+##   salaries[p1] = 30_000
+##
+##   p2.firstName = "소진"
+##   p2.lastName = "박"
+##   salaries[p2] = 45_000
+##
 ## **Note:** The data types declared here have *value semantics*: This means
 ## that ``=`` performs a copy of the hash table.
 
@@ -25,6 +67,7 @@ type
   TTable* {.final, myShallow.}[A, B] = object ## generic hash table
     data: TKeyValuePairSeq[A, B]
     counter: int
+  PTable*[A,B] = ref TTable[A, B]
 
 when not defined(nimhygiene):
   {.pragma: dirty.}
@@ -103,6 +146,14 @@ proc mget*[A, B](t: var TTable[A, B], key: A): var B =
   if index >= 0: result = t.data[index].val
   else: raise newException(EInvalidKey, "key not found: " & $key)
 
+iterator allValues*[A, B](t: TTable[A, B]; key: A): B =
+  ## iterates over any value in the table `t` that belongs to the given `key`.
+  var h: THash = hash(key) and high(t.data)
+  while t.data[h].slot != seEmpty:
+    if t.data[h].key == key and t.data[h].slot == seFilled:
+      yield t.data[h].val
+    h = nextTry(h, high(t.data))
+
 proc hasKey*[A, B](t: TTable[A, B], key: A): bool =
   ## returns true iff `key` is in the table `t`.
   result = rawGet(t, key) >= 0
@@ -190,7 +241,7 @@ proc `$`*[A, B](t: TTable[A, B]): string =
   ## The `$` operator for hash tables.
   dollarImpl()
   
-proc `==`*[A, B](s, t: TTable[A, B]): bool =
+template equalsImpl() =
   if s.counter == t.counter:
     # different insertion orders mean different 'data' seqs, so we have
     # to use the slow route here:
@@ -199,6 +250,9 @@ proc `==`*[A, B](s, t: TTable[A, B]): bool =
       if t[key] != val: return false
     return true
   
+proc `==`*[A, B](s, t: TTable[A, B]): bool =
+  equalsImpl()
+  
 proc indexBy*[A, B, C](collection: A, index: proc(x: B): C): TTable[C, B] =
   ## Index the collection with the proc provided.
   # TODO: As soon as supported, change collection: A to collection: A[B]
@@ -206,6 +260,87 @@ proc indexBy*[A, B, C](collection: A, index: proc(x: B): C): TTable[C, B] =
   for item in collection:
     result[index(item)] = item
 
+proc len*[A, B](t: PTable[A, B]): int =
+  ## returns the number of keys in `t`.
+  result = t.counter
+
+iterator pairs*[A, B](t: PTable[A, B]): tuple[key: A, val: B] =
+  ## iterates over any (key, value) pair in the table `t`.
+  for h in 0..high(t.data):
+    if t.data[h].slot == seFilled: yield (t.data[h].key, t.data[h].val)
+
+iterator mpairs*[A, B](t: PTable[A, B]): tuple[key: A, val: var B] =
+  ## iterates over any (key, value) pair in the table `t`. The values
+  ## can be modified.
+  for h in 0..high(t.data):
+    if t.data[h].slot == seFilled: yield (t.data[h].key, t.data[h].val)
+
+iterator keys*[A, B](t: PTable[A, B]): A =
+  ## iterates over any key in the table `t`.
+  for h in 0..high(t.data):
+    if t.data[h].slot == seFilled: yield t.data[h].key
+
+iterator values*[A, B](t: PTable[A, B]): B =
+  ## iterates over any value in the table `t`.
+  for h in 0..high(t.data):
+    if t.data[h].slot == seFilled: yield t.data[h].val
+
+iterator mvalues*[A, B](t: PTable[A, B]): var B =
+  ## iterates over any value in the table `t`. The values can be modified.
+  for h in 0..high(t.data):
+    if t.data[h].slot == seFilled: yield t.data[h].val
+
+proc `[]`*[A, B](t: PTable[A, B], key: A): B =
+  ## retrieves the value at ``t[key]``. If `key` is not in `t`,
+  ## default empty value for the type `B` is returned
+  ## and no exception is raised. One can check with ``hasKey`` whether the key
+  ## exists.
+  result = t[][key]
+
+proc mget*[A, B](t: PTable[A, B], key: A): var B =
+  ## retrieves the value at ``t[key]``. The value can be modified.
+  ## If `key` is not in `t`, the ``EInvalidKey`` exception is raised.
+  t[].mget(key)
+
+proc hasKey*[A, B](t: PTable[A, B], key: A): bool =
+  ## returns true iff `key` is in the table `t`.
+  result = t[].hasKey(key)
+
+proc `[]=`*[A, B](t: PTable[A, B], key: A, val: B) =
+  ## puts a (key, value)-pair into `t`.
+  t[][key] = val
+
+proc add*[A, B](t: PTable[A, B], key: A, val: B) =
+  ## puts a new (key, value)-pair into `t` even if ``t[key]`` already exists.
+  t[].add(key, val)
+  
+proc del*[A, B](t: PTable[A, B], key: A) =
+  ## deletes `key` from hash table `t`.
+  t[].del(key)
+
+proc newTable*[A, B](initialSize=64): PTable[A, B] =
+  new(result)
+  result[] = initTable[A, B](initialSize)
+
+proc newTable*[A, B](pairs: openArray[tuple[key: A, val: B]]): PTable[A, B] =
+  ## creates a new hash table that contains the given `pairs`.
+  new(result)
+  result[] = toTable[A, B](pairs)
+
+proc `$`*[A, B](t: PTable[A, B]): string =
+  ## The `$` operator for hash tables.
+  dollarImpl()
+
+proc `==`*[A, B](s, t: PTable[A, B]): bool =
+  equalsImpl()
+
+proc newTableFrom*[A, B, C](collection: A, index: proc(x: B): C): PTable[C, B] =
+  ## Index the collection with the proc provided.
+  # TODO: As soon as supported, change collection: A to collection: A[B]
+  result = newTable[C, B]()
+  for item in collection:
+    result[index(item)] = item
+
 # ------------------------------ ordered table ------------------------------
 
 type
@@ -216,6 +351,7 @@ type
       final, myShallow.}[A, B] = object ## table that remembers insertion order
     data: TOrderedKeyValuePairSeq[A, B]
     counter, first, last: int
+  POrderedTable*[A, B] = ref TOrderedTable[A, B]
 
 proc len*[A, B](t: TOrderedTable[A, B]): int {.inline.} =
   ## returns the number of keys in `t`.
@@ -376,6 +512,96 @@ proc sort*[A, B](t: var TOrderedTable[A, B],
   t.first = list
   t.last = tail
 
+proc len*[A, B](t: POrderedTable[A, B]): int {.inline.} =
+  ## returns the number of keys in `t`.
+  result = t.counter
+
+template forAllOrderedPairs(yieldStmt: stmt) {.dirty, immediate.} =
+  var h = t.first
+  while h >= 0:
+    var nxt = t.data[h].next
+    if t.data[h].slot == seFilled: yieldStmt
+    h = nxt
+
+iterator pairs*[A, B](t: POrderedTable[A, B]): tuple[key: A, val: B] =
+  ## iterates over any (key, value) pair in the table `t` in insertion
+  ## order.
+  forAllOrderedPairs:
+    yield (t.data[h].key, t.data[h].val)
+
+iterator mpairs*[A, B](t: POrderedTable[A, B]): tuple[key: A, val: var B] =
+  ## iterates over any (key, value) pair in the table `t` in insertion
+  ## order. The values can be modified.
+  forAllOrderedPairs:
+    yield (t.data[h].key, t.data[h].val)
+
+iterator keys*[A, B](t: POrderedTable[A, B]): A =
+  ## iterates over any key in the table `t` in insertion order.
+  forAllOrderedPairs:
+    yield t.data[h].key
+
+iterator values*[A, B](t: POrderedTable[A, B]): B =
+  ## iterates over any value in the table `t` in insertion order.
+  forAllOrderedPairs:
+    yield t.data[h].val
+
+iterator mvalues*[A, B](t: POrderedTable[A, B]): var B =
+  ## iterates over any value in the table `t` in insertion order. The values
+  ## can be modified.
+  forAllOrderedPairs:
+    yield t.data[h].val
+
+proc `[]`*[A, B](t: POrderedTable[A, B], key: A): B =
+  ## retrieves the value at ``t[key]``. If `key` is not in `t`,
+  ## default empty value for the type `B` is returned
+  ## and no exception is raised. One can check with ``hasKey`` whether the key
+  ## exists.
+  result = t[][key]
+
+proc mget*[A, B](t: POrderedTable[A, B], key: A): var B =
+  ## retrieves the value at ``t[key]``. The value can be modified.
+  ## If `key` is not in `t`, the ``EInvalidKey`` exception is raised.
+  result = t[].mget(key)
+
+proc hasKey*[A, B](t: POrderedTable[A, B], key: A): bool =
+  ## returns true iff `key` is in the table `t`.
+  result = t[].hasKey(key)
+
+proc `[]=`*[A, B](t: POrderedTable[A, B], key: A, val: B) =
+  ## puts a (key, value)-pair into `t`.
+  t[][key] = val
+
+proc add*[A, B](t: POrderedTable[A, B], key: A, val: B) =
+  ## puts a new (key, value)-pair into `t` even if ``t[key]`` already exists.
+  t[].add(key, val)
+
+proc newOrderedTable*[A, B](initialSize=64): POrderedTable[A, B] =
+  ## creates a new ordered hash table that is empty.
+  ##
+  ## `initialSize` needs to be a power of two. If you need to accept runtime
+  ## values for this you could use the ``nextPowerOfTwo`` proc from the
+  ## `math <math.html>`_ module.
+  new(result)
+  result[] = initOrderedTable[A, B]()
+
+proc newOrderedTable*[A, B](pairs: openArray[tuple[key: A, 
+                           val: B]]): POrderedTable[A, B] =
+  ## creates a new ordered hash table that contains the given `pairs`.
+  result = newOrderedTable[A, B](nextPowerOfTwo(pairs.len+10))
+  for key, val in items(pairs): result[key] = val
+
+proc `$`*[A, B](t: POrderedTable[A, B]): string =
+  ## The `$` operator for ordered hash tables.
+  dollarImpl()
+
+proc sort*[A, B](t: POrderedTable[A, B], 
+                 cmp: proc (x,y: tuple[key: A, val: B]): int) =
+  ## sorts `t` according to `cmp`. This modifies the internal list
+  ## that kept the insertion order, so insertion order is lost after this
+  ## call but key lookup and insertions remain possible after `sort` (in
+  ## contrast to the `sort` for count tables).
+  t[].sort(cmp)
+
 # ------------------------------ count tables -------------------------------
 
 type
@@ -383,6 +609,7 @@ type
       A] = object ## table that counts the number of each key
     data: seq[tuple[key: A, val: int]]
     counter: int
+  PCountTable*[A] = ref TCountTable[A]
 
 proc len*[A](t: TCountTable[A]): int =
   ## returns the number of keys in `t`.
@@ -526,3 +753,118 @@ proc sort*[A](t: var TCountTable[A]) =
         if j < h: break
     if h == 1: break
 
+proc len*[A](t: PCountTable[A]): int =
+  ## returns the number of keys in `t`.
+  result = t.counter
+
+iterator pairs*[A](t: PCountTable[A]): tuple[key: A, val: int] =
+  ## iterates over any (key, value) pair in the table `t`.
+  for h in 0..high(t.data):
+    if t.data[h].val != 0: yield (t.data[h].key, t.data[h].val)
+
+iterator mpairs*[A](t: PCountTable[A]): tuple[key: A, val: var int] =
+  ## iterates over any (key, value) pair in the table `t`. The values can
+  ## be modified.
+  for h in 0..high(t.data):
+    if t.data[h].val != 0: yield (t.data[h].key, t.data[h].val)
+
+iterator keys*[A](t: PCountTable[A]): A =
+  ## iterates over any key in the table `t`.
+  for h in 0..high(t.data):
+    if t.data[h].val != 0: yield t.data[h].key
+
+iterator values*[A](t: PCountTable[A]): int =
+  ## iterates over any value in the table `t`.
+  for h in 0..high(t.data):
+    if t.data[h].val != 0: yield t.data[h].val
+
+iterator mvalues*[A](t: PCountTable[A]): var int =
+  ## iterates over any value in the table `t`. The values can be modified.
+  for h in 0..high(t.data):
+    if t.data[h].val != 0: yield t.data[h].val
+
+proc `[]`*[A](t: PCountTable[A], key: A): int =
+  ## retrieves the value at ``t[key]``. If `key` is not in `t`,
+  ## 0 is returned. One can check with ``hasKey`` whether the key
+  ## exists.
+  result = t[][key]
+
+proc mget*[A](t: PCountTable[A], key: A): var int =
+  ## retrieves the value at ``t[key]``. The value can be modified.
+  ## If `key` is not in `t`, the ``EInvalidKey`` exception is raised.
+  result = t[].mget(key)
+
+proc hasKey*[A](t: PCountTable[A], key: A): bool =
+  ## returns true iff `key` is in the table `t`.
+  result = t[].hasKey(key)
+
+proc `[]=`*[A](t: PCountTable[A], key: A, val: int) =
+  ## puts a (key, value)-pair into `t`. `val` has to be positive.
+  assert val > 0
+  t[][key] = val
+
+proc newCountTable*[A](initialSize=64): PCountTable[A] =
+  ## creates a new count table that is empty.
+  ##
+  ## `initialSize` needs to be a power of two. If you need to accept runtime
+  ## values for this you could use the ``nextPowerOfTwo`` proc from the
+  ## `math <math.html>`_ module.
+  new(result)
+  result[] = initCountTable[A](initialSize)
+
+proc newCountTable*[A](keys: openArray[A]): PCountTable[A] =
+  ## creates a new count table with every key in `keys` having a count of 1.
+  result = newCountTable[A](nextPowerOfTwo(keys.len+10))
+  for key in items(keys): result[key] = 1
+
+proc `$`*[A](t: PCountTable[A]): string =
+  ## The `$` operator for count tables.
+  dollarImpl()
+
+proc inc*[A](t: PCountTable[A], key: A, val = 1) = 
+  ## increments `t[key]` by `val`.
+  t[].inc(key, val)
+
+proc smallest*[A](t: PCountTable[A]): tuple[key: A, val: int] =
+  ## returns the largest (key,val)-pair. Efficiency: O(n)
+  t[].smallest
+
+proc largest*[A](t: PCountTable[A]): tuple[key: A, val: int] =
+  ## returns the (key,val)-pair with the largest `val`. Efficiency: O(n)
+  t[].largest
+
+proc sort*[A](t: PCountTable[A]) =
+  ## sorts the count table so that the entry with the highest counter comes
+  ## first. This is destructive! You must not modify `t` afterwards!
+  ## You can use the iterators `pairs`,  `keys`, and `values` to iterate over
+  ## `t` in the sorted order.
+  t[].sort
+
+when isMainModule:
+  type
+    Person = object
+      firstName, lastName: string
+
+  proc hash(x: Person): THash =
+    ## Piggyback on the already available string hash proc.
+    ##
+    ## Without this proc nothing works!
+    result = x.firstName.hash !& x.lastName.hash
+    result = !$result
+
+  var
+    salaries = initTable[Person, int]()
+    p1, p2: Person
+  p1.firstName = "Jon"
+  p1.lastName = "Ross"
+  salaries[p1] = 30_000
+  p2.firstName = "소진"
+  p2.lastName = "박"
+  salaries[p2] = 45_000
+  var
+    s2 = initOrderedTable[Person, int]()
+    s3 = initCountTable[Person]()
+  s2[p1] = 30_000
+  s2[p2] = 45_000
+  s3[p1] = 30_000
+  s3[p2] = 45_000
diff --git a/lib/pure/concurrency/cpuinfo.nim b/lib/pure/concurrency/cpuinfo.nim
new file mode 100644
index 000000000..dfa819f64
--- /dev/null
+++ b/lib/pure/concurrency/cpuinfo.nim
@@ -0,0 +1,58 @@
+#
+#
+#            Nimrod's Runtime Library
+#        (c) Copyright 2014 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## This module implements procs to determine the number of CPUs / cores.
+
+include "system/inclrtl"
+
+import strutils, os
+
+when not defined(windows):
+  import posix
+
+when defined(linux):
+  import linux
+
+when defined(macosx) or defined(bsd):
+  const
+    CTL_HW = 6
+    HW_AVAILCPU = 25
+    HW_NCPU = 3
+  proc sysctl(x: ptr array[0..3, cint], y: cint, z: pointer,
+              a: var csize, b: pointer, c: int): cint {.
+             importc: "sysctl", header: "<sys/sysctl.h>".}
+
+proc countProcessors*(): int {.rtl, extern: "ncpi$1".} =
+  ## returns the numer of the processors/cores the machine has.
+  ## Returns 0 if it cannot be detected.
+  when defined(windows):
+    var x = getEnv("NUMBER_OF_PROCESSORS")
+    if x.len > 0: result = parseInt(x.string)
+  elif defined(macosx) or defined(bsd):
+    var
+      mib: array[0..3, cint]
+      numCPU: int
+      len: csize
+    mib[0] = CTL_HW
+    mib[1] = HW_AVAILCPU
+    len = sizeof(numCPU)
+    discard sysctl(addr(mib), 2, addr(numCPU), len, nil, 0)
+    if numCPU < 1:
+      mib[1] = HW_NCPU
+      discard sysctl(addr(mib), 2, addr(numCPU), len, nil, 0)
+    result = numCPU
+  elif defined(hpux):
+    result = mpctl(MPC_GETNUMSPUS, nil, nil)
+  elif defined(irix):
+    var SC_NPROC_ONLN {.importc: "_SC_NPROC_ONLN", header: "<unistd.h>".}: cint
+    result = sysconf(SC_NPROC_ONLN)
+  else:
+    result = sysconf(SC_NPROCESSORS_ONLN)
+  if result <= 0: result = 1
+
diff --git a/lib/pure/concurrency/cpuload.nim b/lib/pure/concurrency/cpuload.nim
new file mode 100644
index 000000000..3cf6a7392
--- /dev/null
+++ b/lib/pure/concurrency/cpuload.nim
@@ -0,0 +1,96 @@
+#
+#
+#            Nimrod's Runtime Library
+#        (c) Copyright 2014 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## This module implements a helper for a thread pool to determine whether
+## creating a thread is a good idea.
+
+when defined(windows):
+  import winlean, os, strutils, math
+
+  proc `-`(a, b: TFILETIME): int64 = a.rdFileTime - b.rdFileTime
+elif defined(linux):
+  from cpuinfo import countProcessors
+
+type
+  ThreadPoolAdvice* = enum
+    doNothing,
+    doCreateThread,  # create additional thread for throughput
+    doShutdownThread # too many threads are busy, shutdown one
+
+  ThreadPoolState* = object
+    when defined(windows):
+      prevSysKernel, prevSysUser, prevProcKernel, prevProcUser: TFILETIME
+    calls*: int
+
+proc advice*(s: var ThreadPoolState): ThreadPoolAdvice =
+  when defined(windows):
+    var
+      sysIdle, sysKernel, sysUser,
+        procCreation, procExit, procKernel, procUser: TFILETIME
+    if getSystemTimes(sysIdle, sysKernel, sysUser) == 0 or
+        getProcessTimes(THandle(-1), procCreation, procExit, 
+                        procKernel, procUser) == 0:
+      return doNothing
+    if s.calls > 0:
+      let
+        sysKernelDiff = sysKernel - s.prevSysKernel
+        sysUserDiff = sysUser - s.prevSysUser
+
+        procKernelDiff = procKernel - s.prevProcKernel
+        procUserDiff = procUser - s.prevProcUser
+
+        sysTotal = int(sysKernelDiff + sysUserDiff)
+        procTotal = int(procKernelDiff + procUserDiff)
+      # total CPU usage < 85% --> create a new worker thread.
+      # Measurements show that 100% and often even 90% is not reached even
+      # if all my cores are busy.
+      if sysTotal == 0 or procTotal / sysTotal < 0.85:
+        result = doCreateThread
+    s.prevSysKernel = sysKernel
+    s.prevSysUser = sysUser
+    s.prevProcKernel = procKernel
+    s.prevProcUser = procUser
+  elif defined(linux):
+    proc fscanf(c: TFile, frmt: cstring) {.varargs, importc, 
+      header: "<stdio.h>".}
+
+    var f = open("/proc/loadavg")
+    var b: float
+    var busy, total: int
+    fscanf(f,"%lf %lf %lf %ld/%ld",
+           addr b, addr b, addr b, addr busy, addr total)
+    f.close()
+    let cpus = countProcessors()
+    if busy-1 < cpus:
+      result = doCreateThread
+    elif busy-1 >= cpus*2:
+      result = doShutdownThread
+    else:
+      result = doNothing
+  else:
+    # XXX implement this for other OSes
+    result = doNothing
+  inc s.calls
+
+when isMainModule:
+  proc busyLoop() =
+    while true:
+      discard random(80)
+      os.sleep(100)
+
+  spawn busyLoop()
+  spawn busyLoop()
+  spawn busyLoop()
+  spawn busyLoop()
+
+  var s: ThreadPoolState
+
+  for i in 1 .. 70:
+    echo advice(s)
+    os.sleep(1000)
diff --git a/lib/pure/concurrency/threadpool.nim b/lib/pure/concurrency/threadpool.nim
new file mode 100644
index 000000000..fd1041918
--- /dev/null
+++ b/lib/pure/concurrency/threadpool.nim
@@ -0,0 +1,378 @@
+#
+#
+#            Nimrod's Runtime Library
+#        (c) Copyright 2014 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+## Implements Nimrod's 'spawn'.
+
+import cpuinfo, cpuload, locks
+
+{.push stackTrace:off.}
+
+type
+  CondVar = object
+    c: TCond
+    L: TLock
+    counter: int
+
+proc createCondVar(): CondVar =
+  initCond(result.c)
+  initLock(result.L)
+
+proc destroyCondVar(cv: var CondVar) {.inline.} =
+  deinitCond(cv.c)
+  deinitLock(cv.L)
+
+proc await(cv: var CondVar) =
+  acquire(cv.L)
+  while cv.counter <= 0:
+    wait(cv.c, cv.L)
+  dec cv.counter
+  release(cv.L)
+
+proc signal(cv: var CondVar) =
+  acquire(cv.L)
+  inc cv.counter
+  release(cv.L)
+  signal(cv.c)
+
+const CacheLineSize = 32 # true for most archs
+
+type
+  Barrier {.compilerProc.} = object
+    entered: int
+    cv: CondVar # condvar takes 3 words at least
+    when sizeof(int) < 8:
+      cacheAlign: array[CacheLineSize-4*sizeof(int), byte]
+    left: int
+    cacheAlign2: array[CacheLineSize-sizeof(int), byte]
+    interest: bool ## wether the master is interested in the "all done" event
+
+proc barrierEnter(b: ptr Barrier) {.compilerProc, inline.} =
+  # due to the signaling between threads, it is ensured we are the only
+  # one with access to 'entered' so we don't need 'atomicInc' here:
+  inc b.entered
+  # also we need no 'fence' instructions here as soon 'nimArgsPassingDone'
+  # will be called which already will perform a fence for us.
+
+proc barrierLeave(b: ptr Barrier) {.compilerProc, inline.} =
+  atomicInc b.left
+  when not defined(x86): fence()
+  if b.interest and b.left == b.entered: signal(b.cv)
+
+proc openBarrier(b: ptr Barrier) {.compilerProc, inline.} =
+  b.entered = 0
+  b.left = 0
+  b.interest = false
+
+proc closeBarrier(b: ptr Barrier) {.compilerProc.} =
+  fence()
+  if b.left != b.entered:
+    b.cv = createCondVar()
+    fence()
+    b.interest = true
+    fence()
+    while b.left != b.entered: await(b.cv)
+    destroyCondVar(b.cv)
+
+{.pop.}
+
+# ----------------------------------------------------------------------------
+
+type
+  foreign* = object ## a region that indicates the pointer comes from a
+                    ## foreign thread heap.
+  AwaitInfo = object
+    cv: CondVar
+    idx: int
+
+  FlowVarBase* = ref FlowVarBaseObj ## untyped base class for 'FlowVar[T]'
+  FlowVarBaseObj = object of TObject
+    ready, usesCondVar: bool
+    cv: CondVar #\
+    # for 'awaitAny' support
+    ai: ptr AwaitInfo
+    idx: int
+    data: pointer  # we incRef and unref it to keep it alive
+    owner: pointer # ptr Worker
+
+  FlowVarObj[T] = object of FlowVarBaseObj
+    blob: T
+
+  FlowVar*{.compilerProc.}[T] = ref FlowVarObj[T] ## a data flow variable
+
+  ToFreeQueue = object
+    len: int
+    lock: TLock
+    empty: TCond
+    data: array[512, pointer]
+
+  WorkerProc = proc (thread, args: pointer) {.nimcall, gcsafe.}
+  Worker = object
+    taskArrived: CondVar
+    taskStarted: CondVar #\
+    # task data:
+    f: WorkerProc
+    data: pointer
+    ready: bool # put it here for correct alignment!
+    initialized: bool # whether it has even been initialized
+    shutdown: bool # the pool requests to shut down this worker thread
+    q: ToFreeQueue
+
+proc await*(fv: FlowVarBase) =
+  ## waits until the value for the flowVar arrives. Usually it is not necessary
+  ## to call this explicitly.
+  if fv.usesCondVar:
+    fv.usesCondVar = false
+    await(fv.cv)
+    destroyCondVar(fv.cv)
+
+proc finished(fv: FlowVarBase) =
+  doAssert fv.ai.isNil, "flowVar is still attached to an 'awaitAny'"
+  # we have to protect against the rare cases where the owner of the flowVar
+  # simply disregards the flowVar and yet the "flowVarr" has not yet written
+  # anything to it:
+  await(fv)
+  if fv.data.isNil: return
+  let owner = cast[ptr Worker](fv.owner)
+  let q = addr(owner.q)
+  var waited = false
+  while true:
+    acquire(q.lock)
+    if q.len < q.data.len:
+      q.data[q.len] = fv.data
+      inc q.len
+      release(q.lock)
+      break
+    else:
+      # the queue is exhausted! We block until it has been cleaned:
+      release(q.lock)
+      wait(q.empty, q.lock)
+      waited = true
+  fv.data = nil
+  # wakeup other potentially waiting threads:
+  if waited: signal(q.empty)
+
+proc cleanFlowVars(w: ptr Worker) =
+  let q = addr(w.q)
+  acquire(q.lock)
+  for i in 0 .. <q.len:
+    GC_unref(cast[PObject](q.data[i]))
+  q.len = 0
+  release(q.lock)
+  signal(q.empty)
+
+proc fvFinalizer[T](fv: FlowVar[T]) = finished(fv)
+
+proc nimCreateFlowVar[T](): FlowVar[T] {.compilerProc.} =
+  new(result, fvFinalizer)
+
+proc nimFlowVarCreateCondVar(fv: FlowVarBase) {.compilerProc.} =
+  fv.cv = createCondVar()
+  fv.usesCondVar = true
+
+proc nimFlowVarSignal(fv: FlowVarBase) {.compilerProc.} =
+  if fv.ai != nil:
+    acquire(fv.ai.cv.L)
+    fv.ai.idx = fv.idx
+    inc fv.ai.cv.counter
+    release(fv.ai.cv.L)
+    signal(fv.ai.cv.c)
+  if fv.usesCondVar: signal(fv.cv)
+
+proc awaitAndThen*[T](fv: FlowVar[T]; action: proc (x: T) {.closure.}) =
+  ## blocks until the ``fv`` is available and then passes its value
+  ## to ``action``. Note that due to Nimrod's parameter passing semantics this
+  ## means that ``T`` doesn't need to be copied and so ``awaitAndThen`` can
+  ## sometimes be more efficient than ``^``.
+  await(fv)
+  when T is string or T is seq:
+    action(cast[T](fv.data))
+  elif T is ref:
+    {.error: "'awaitAndThen' not available for FlowVar[ref]".}
+  else:
+    action(fv.blob)
+  finished(fv)
+
+proc `^`*[T](fv: FlowVar[ref T]): foreign ptr T =
+  ## blocks until the value is available and then returns this value.
+  await(fv)
+  result = cast[foreign ptr T](fv.data)
+
+proc `^`*[T](fv: FlowVar[T]): T =
+  ## blocks until the value is available and then returns this value.
+  await(fv)
+  when T is string or T is seq:
+    result = cast[T](fv.data)
+  else:
+    result = fv.blob
+
+proc awaitAny*(flowVars: openArray[FlowVarBase]): int =
+  ## awaits any of the given flowVars. Returns the index of one flowVar for
+  ## which a value arrived. A flowVar only supports one call to 'awaitAny' at
+  ## the same time. That means if you await([a,b]) and await([b,c]) the second
+  ## call will only await 'c'. If there is no flowVar left to be able to wait
+  ## on, -1 is returned.
+  ## **Note**: This results in non-deterministic behaviour and so should be
+  ## avoided.
+  var ai: AwaitInfo
+  ai.cv = createCondVar()
+  var conflicts = 0
+  for i in 0 .. flowVars.high:
+    if cas(addr flowVars[i].ai, nil, addr ai):
+      flowVars[i].idx = i
+    else:
+      inc conflicts
+  if conflicts < flowVars.len:
+    await(ai.cv)
+    result = ai.idx
+    for i in 0 .. flowVars.high:
+      discard cas(addr flowVars[i].ai, addr ai, nil)
+  else:
+    result = -1
+  destroyCondVar(ai.cv)
+
+proc nimArgsPassingDone(p: pointer) {.compilerProc.} =
+  let w = cast[ptr Worker](p)
+  signal(w.taskStarted)
+
+const
+  MaxThreadPoolSize* = 256 ## maximal size of the thread pool. 256 threads
+                           ## should be good enough for anybody ;-)
+
+var
+  currentPoolSize: int
+  maxPoolSize = MaxThreadPoolSize
+  minPoolSize = 4
+  gSomeReady = createCondVar()
+  readyWorker: ptr Worker
+
+proc slave(w: ptr Worker) {.thread.} =
+  while true:
+    w.ready = true
+    readyWorker = w
+    signal(gSomeReady)
+    await(w.taskArrived)
+    assert(not w.ready)
+    w.f(w, w.data)
+    if w.q.len != 0: w.cleanFlowVars
+    if w.shutdown:
+      w.shutdown = false
+      atomicDec currentPoolSize
+
+proc setMinPoolSize*(size: range[1..MaxThreadPoolSize]) =
+  ## sets the minimal thread pool size. The default value of this is 4.
+  minPoolSize = size
+
+proc setMaxPoolSize*(size: range[1..MaxThreadPoolSize]) =
+  ## sets the minimal thread pool size. The default value of this
+  ## is ``MaxThreadPoolSize``.
+  maxPoolSize = size
+
+var
+  workers: array[MaxThreadPoolSize, TThread[ptr Worker]]
+  workersData: array[MaxThreadPoolSize, Worker]
+
+proc activateThread(i: int) {.noinline.} =
+  workersData[i].taskArrived = createCondVar()
+  workersData[i].taskStarted = createCondVar()
+  workersData[i].initialized = true
+  initCond(workersData[i].q.empty)
+  initLock(workersData[i].q.lock)
+  createThread(workers[i], slave, addr(workersData[i]))
+
+proc setup() =
+  currentPoolSize = min(countProcessors(), MaxThreadPoolSize)
+  readyWorker = addr(workersData[0])
+  for i in 0.. <currentPoolSize: activateThread(i)
+
+proc preferSpawn*(): bool =
+  ## Use this proc to determine quickly if a 'spawn' or a direct call is
+  ## preferable. If it returns 'true' a 'spawn' may make sense. In general
+  ## it is not necessary to call this directly; use 'spawnX' instead.
+  result = gSomeReady.counter > 0
+
+proc spawn*(call: expr): expr {.magic: "Spawn".}
+  ## always spawns a new task, so that the 'call' is never executed on
+  ## the calling thread. 'call' has to be proc call 'p(...)' where 'p'
+  ## is gcsafe and has a return type that is either 'void' or compatible
+  ## with ``FlowVar[T]``.
+
+template spawnX*(call: expr): expr =
+  ## spawns a new task if a CPU core is ready, otherwise executes the
+  ## call in the calling thread. Usually it is advised to
+  ## use 'spawn' in order to not block the producer for an unknown
+  ## amount of time. 'call' has to be proc call 'p(...)' where 'p'
+  ## is gcsafe and has a return type that is either 'void' or compatible
+  ## with ``FlowVar[T]``.
+  (if preferSpawn(): spawn call else: call)
+
+proc parallel*(body: stmt) {.magic: "Parallel".}
+  ## a parallel section can be used to execute a block in parallel. ``body``
+  ## has to be in a DSL that is a particular subset of the language. Please
+  ## refer to the manual for further information.
+
+var
+  state: ThreadPoolState
+  stateLock: TLock
+
+initLock stateLock
+
+proc selectWorker(w: ptr Worker; fn: WorkerProc; data: pointer): bool =
+  if cas(addr w.ready, true, false):
+    w.data = data
+    w.f = fn
+    signal(w.taskArrived)
+    await(w.taskStarted)
+    result = true
+
+proc nimSpawn(fn: WorkerProc; data: pointer) {.compilerProc.} =
+  # implementation of 'spawn' that is used by the code generator.
+  while true:
+    if selectWorker(readyWorker, fn, data): return
+    for i in 0.. <currentPoolSize:
+      if selectWorker(addr(workersData[i]), fn, data): return
+    # determine what to do, but keep in mind this is expensive too:
+    # state.calls < maxPoolSize: warmup phase
+    # (state.calls and 127) == 0: periodic check
+    if state.calls < maxPoolSize or (state.calls and 127) == 0:
+      # ensure the call to 'advice' is atomic:
+      if tryAcquire(stateLock):
+        case advice(state)
+        of doNothing: discard
+        of doCreateThread:
+          if currentPoolSize < maxPoolSize:
+            if not workersData[currentPoolSize].initialized:
+              activateThread(currentPoolSize)
+            let w = addr(workersData[currentPoolSize])
+            atomicInc currentPoolSize
+            if selectWorker(w, fn, data):
+              release(stateLock)
+              return
+            # else we didn't succeed but some other thread, so do nothing.
+        of doShutdownThread:
+          if currentPoolSize > minPoolSize:
+            let w = addr(workersData[currentPoolSize-1])
+            w.shutdown = true
+          # we don't free anything here. Too dangerous.
+        release(stateLock)
+      # else the acquire failed, but this means some
+      # other thread succeeded, so we don't need to do anything here.
+    await(gSomeReady)
+
+proc sync*() =
+  ## a simple barrier to wait for all spawn'ed tasks. If you need more elaborate
+  ## waiting, you have to use an explicit barrier.
+  while true:
+    var allReady = true
+    for i in 0 .. <currentPoolSize:
+      if not allReady: break
+      allReady = allReady and workersData[i].ready
+    if allReady: break
+    await(gSomeReady)
+
+setup()
diff --git a/lib/pure/fsmonitor.nim b/lib/pure/fsmonitor.nim
index d6584c1a0..b35466771 100644
--- a/lib/pure/fsmonitor.nim
+++ b/lib/pure/fsmonitor.nim
@@ -119,8 +119,8 @@ proc getEvent(m: PFSMonitor, fd: cint): seq[TMonitorEvent] =
     var mev: TMonitorEvent
     mev.wd = event.wd
     if event.len.int != 0:
-      mev.name = newString(event.len.int)
-      copyMem(addr(mev.name[0]), addr event.name, event.len.int-1)
+      let cstr = event.name.addr.cstring
+      mev.name = $cstr
     else:
       mev.name = ""
     
@@ -211,4 +211,4 @@ when isMainModule:
       
   while true:
     if not disp.poll(): break
-  
\ No newline at end of file
+  
diff --git a/lib/pure/future.nim b/lib/pure/future.nim
index e0e4c4176..b7df05207 100644
--- a/lib/pure/future.nim
+++ b/lib/pure/future.nim
@@ -18,7 +18,6 @@ proc createProcType(p, b: PNimrodNode): PNimrodNode {.compileTime.} =
   result = newNimNode(nnkProcTy)
   var formalParams = newNimNode(nnkFormalParams)
 
-  expectKind(b, nnkIdent)
   formalParams.add b
 
   case p.kind
diff --git a/lib/pure/hashes.nim b/lib/pure/hashes.nim
index 5784a96c1..740355e55 100644
--- a/lib/pure/hashes.nim
+++ b/lib/pure/hashes.nim
@@ -8,7 +8,34 @@
 #
 
 ## This module implements efficient computations of hash values for diverse
-## Nimrod types.
+## Nimrod types. All the procs are based on these two building blocks: the `!&
+## proc <#!&>`_ used to start or mix a hash value, and the `!$ proc <#!$>`_
+## used to *finish* the hash value.  If you want to implement hash procs for
+## your custom types you will end up writing the following kind of skeleton of
+## code:
+##
+## .. code-block:: nimrod
+##  proc hash(x: Something): THash =
+##    ## Computes a THash from `x`.
+##    var h: THash = 0
+##    # Iterate over parts of `x`.
+##    for xAtom in x:
+##      # Mix the atom with the partial hash.
+##      h = h !& xAtom
+##    # Finish the hash.
+##    result = !$h
+##
+## If your custom types contain fields for which there already is a hash proc,
+## like for example objects made up of ``strings``, you can simply hash
+## together the hash value of the individual fields:
+##
+## .. code-block:: nimrod
+##  proc hash(x: Something): THash =
+##    ## Computes a THash from `x`.
+##    var h: THash = 0
+##    h = h &! hash(x.foo)
+##    h = h &! hash(x.bar)
+##    result = !$h
 
 import 
   strutils
diff --git a/lib/pure/httpclient.nim b/lib/pure/httpclient.nim
index be06a7b8e..9bacc80d6 100644
--- a/lib/pure/httpclient.nim
+++ b/lib/pure/httpclient.nim
@@ -654,7 +654,7 @@ when isMainModule:
       resp = await client.request("http://nimrod-lang.org/download.html")
       echo("Got response: ", resp.status)
 
-    main()
+    asyncCheck main()
     runForever()
 
   else:
diff --git a/lib/pure/httpserver.nim b/lib/pure/httpserver.nim
index 8de708c5d..885742b64 100644
--- a/lib/pure/httpserver.nim
+++ b/lib/pure/httpserver.nim
@@ -192,7 +192,7 @@ when false:
     if path[path.len-1] == '/' or existsDir(path):
       path = path / "index.html"
 
-    if not ExistsFile(path):
+    if not existsFile(path):
       discardHeaders(client)
       notFound(client)
     else:
diff --git a/lib/pure/json.nim b/lib/pure/json.nim
index 4250847e5..508e564c5 100644
--- a/lib/pure/json.nim
+++ b/lib/pure/json.nim
@@ -619,6 +619,44 @@ proc `%`*(elements: openArray[PJsonNode]): PJsonNode =
   newSeq(result.elems, elements.len)
   for i, p in pairs(elements): result.elems[i] = p
 
+proc `==`* (a,b: PJsonNode): bool =
+  ## Check two nodes for equality
+  if a.kind != b.kind: false
+  else:
+    case a.kind
+    of JString:
+      a.str == b.str
+    of JInt:
+      a.num == b.num
+    of JFloat:
+      a.fnum == b.fnum
+    of JBool:
+      a.bval == b.bval
+    of JNull:
+      true
+    of JArray:
+      a.elems == b.elems
+    of JObject:
+      a.fields == b.fields
+
+proc hash* (n:PJsonNode): THash =
+  ## Compute the hash for a JSON node
+  case n.kind
+  of JArray:
+    result = hash(n.elems)
+  of JObject:
+    result = hash(n.fields)
+  of JInt:
+    result = hash(n.num)
+  of JFloat:
+    result = hash(n.fnum)
+  of JBool:
+    result = hash(n.bval.int)
+  of JString:
+    result = hash(n.str)
+  of JNull:
+    result = hash(0)
+
 proc len*(n: PJsonNode): int = 
   ## If `n` is a `JArray`, it returns the number of elements.
   ## If `n` is a `JObject`, it returns the number of pairs.
@@ -629,7 +667,9 @@ proc len*(n: PJsonNode): int =
   else: discard
 
 proc `[]`*(node: PJsonNode, name: string): PJsonNode =
-  ## Gets a field from a `JObject`. Returns nil if the key is not found.
+  ## Gets a field from a `JObject`, which must not be nil.
+  ## If the value at `name` does not exist, returns nil
+  assert(not isNil(node))
   assert(node.kind == JObject)
   for key, item in items(node.fields):
     if key == name:
@@ -637,7 +677,9 @@ proc `[]`*(node: PJsonNode, name: string): PJsonNode =
   return nil
   
 proc `[]`*(node: PJsonNode, index: int): PJsonNode =
-  ## Gets the node at `index` in an Array.
+  ## Gets the node at `index` in an Array. Result is undefined if `index`
+  ## is out of bounds
+  assert(not isNil(node))
   assert(node.kind == JArray)
   return node.elems[index]
 
@@ -671,6 +713,23 @@ proc `[]=`*(obj: PJsonNode, key: string, val: PJsonNode) =
       return
   obj.fields.add((key, val))
 
+proc `{}`*(node: PJsonNode, key: string): PJsonNode =
+  ## Transverses the node and gets the given value. If any of the
+  ## names does not exist, returns nil
+  result = node
+  if isNil(node): return nil
+  result = result[key]
+
+proc `{}=`*(node: PJsonNode, names: varargs[string], value: PJsonNode) =
+  ## Transverses the node and tries to set the value at the given location
+  ## to `value` If any of the names are missing, they are added
+  var node = node
+  for i in 0..(names.len-2):
+    if isNil(node[names[i]]):
+      node[names[i]] = newJObject()
+    node = node[names[i]]
+  node[names[names.len-1]] = value
+
 proc delete*(obj: PJsonNode, key: string) =
   ## Deletes ``obj[key]`` preserving the order of the other (key, value)-pairs.
   assert(obj.kind == JObject)
@@ -996,6 +1055,28 @@ when isMainModule:
     raise newException(EInvalidValue, "That line was expected to fail")
   except EInvalidIndex: echo()
 
+  let testJson = parseJson"""{ "a": [1, 2, 3, 4], "b": "asd" }"""
+  # nil passthrough
+  assert(testJson{"doesnt_exist"}{"anything"}.isNil)
+  testJson{["c", "d"]} = %true
+  assert(testJson["c"]["d"].bval)
+
+  # Bounds checking
+  try:
+    let a = testJson["a"][9]
+    assert(false, "EInvalidIndex not thrown")
+  except EInvalidIndex:
+    discard
+  try:
+    let a = testJson["a"][-1]
+    assert(false, "EInvalidIndex not thrown")
+  except EInvalidIndex:
+    discard
+  try:
+    assert(testJson["a"][0].num == 1, "Index doesn't correspond to its value")
+  except:
+    assert(false, "EInvalidIndex thrown for valid index")
+
   discard """
   while true:
     var json = stdin.readLine()
diff --git a/lib/pure/math.nim b/lib/pure/math.nim
index e4aecd272..2f7a696b9 100644
--- a/lib/pure/math.nim
+++ b/lib/pure/math.nim
@@ -10,7 +10,8 @@
 ##   Constructive mathematics is naturally typed. -- Simon Thompson
 ## 
 ## Basic math routines for Nimrod.
-## This module is available for the JavaScript target.
+## This module is available for the `JavaScript target
+## <backends.html#the-javascript-target>`_.
 
 include "system/inclrtl"
 
@@ -135,12 +136,12 @@ proc random*(max: int): int {.gcsafe.}
   ## which initializes the random number generator with a "random"
   ## number, i.e. a tickcount.
 
-when not defined(windows):
-  proc random*(max: float): float {.gcsafe.}
-    ## returns a random number in the range 0..<max. The sequence of
-    ## random number is always the same, unless `randomize` is called
-    ## which initializes the random number generator with a "random"
-    ## number, i.e. a tickcount. This is currently not supported for windows.
+proc random*(max: float): float {.gcsafe.}
+  ## returns a random number in the range 0..<max. The sequence of
+  ## random number is always the same, unless `randomize` is called
+  ## which initializes the random number generator with a "random"
+  ## number, i.e. a tickcount. This has a 16-bit resolution on windows
+  ## and a 48-bit resolution on other platforms.
 
 proc randomize*() {.gcsafe.}
   ## initializes the random number generator with a "random"
@@ -205,7 +206,14 @@ when not defined(JS):
     proc drand48(): float {.importc: "drand48", header: "<stdlib.h>".}
     proc random(max: float): float =
       result = drand48() * max
-    
+  when defined(windows):
+    proc random(max: float): float =
+      # we are hardcodeing this because
+      # importcing macros is extremely problematic
+      # and because the value is publicly documented
+      # on MSDN and very unlikely to change
+      const rand_max = 32767
+      result = (float(rand()) / float(rand_max)) * max
   proc randomize() =
     randomize(cast[int](epochTime()))
 
diff --git a/lib/pure/memfiles.nim b/lib/pure/memfiles.nim
index 807f3da43..31fefc6c8 100644
--- a/lib/pure/memfiles.nim
+++ b/lib/pure/memfiles.nim
@@ -74,9 +74,22 @@ proc unmapMem*(f: var TMemFile, p: pointer, size: int) =
 proc open*(filename: string, mode: TFileMode = fmRead,
            mappedSize = -1, offset = 0, newFileSize = -1): TMemFile =
   ## opens a memory mapped file. If this fails, ``EOS`` is raised.
-  ## `newFileSize` can only be set if the file is not opened with ``fmRead``
-  ## access. `mappedSize` and `offset` can be used to map only a slice of
-  ## the file.
+  ## `newFileSize` can only be set if the file does not exist and is opened
+  ## with write access (e.g., with fmReadWrite). `mappedSize` and `offset`
+  ## can be used to map only a slice of the file. Example:
+  ##
+  ## .. code-block:: nimrod
+  ##   var
+  ##     mm, mm_full, mm_half: TMemFile
+  ##
+  ##   mm = memfiles.open("/tmp/test.mmap", mode = fmWrite, newFileSize = 1024)    # Create a new file
+  ##   mm.close()
+  ##
+  ##   # Read the whole file, would fail if newFileSize was set
+  ##   mm_full = memfiles.open("/tmp/test.mmap", mode = fmReadWrite, mappedSize = -1)
+  ##
+  ##   # Read the first 512 bytes
+  ##   mm_half = memfiles.open("/tmp/test.mmap", mode = fmReadWrite, mappedSize = 512)
 
   # The file can be resized only when write mode is used:
   assert newFileSize == -1 or mode != fmRead
@@ -165,8 +178,11 @@ proc open*(filename: string, mode: TFileMode = fmRead,
 
     if newFileSize != -1:
       flags = flags or O_CREAT or O_TRUNC
+      var permissions_mode = S_IRUSR or S_IWUSR
+      result.handle = open(filename, flags, permissions_mode)
+    else:
+      result.handle = open(filename, flags)
 
-    result.handle = open(filename, flags)
     if result.handle == -1:
       # XXX: errno is supposed to be set here
       # Is there an exception that wraps it?
diff --git a/lib/pure/net.nim b/lib/pure/net.nim
index 74739630b..ddc2bbe2d 100644
--- a/lib/pure/net.nim
+++ b/lib/pure/net.nim
@@ -11,7 +11,7 @@
 
 {.deadCodeElim: on.}
 import rawsockets, os, strutils, unsigned, parseutils, times
-export TPort
+export TPort, `$`
 
 const useWinVersion = defined(Windows) or defined(nimdoc)
 
@@ -350,6 +350,30 @@ type
 
   ETimeout* = object of ESynch
 
+  TSocketFlags* {.pure.} = enum
+    Peek,
+    SafeDisconn ## Ensures disconnection exceptions (ECONNRESET, EPIPE etc) are not thrown.
+
+proc isDisconnectionError*(flags: set[TSocketFlags],
+    lastError: TOSErrorCode): bool =
+  ## Determines whether ``lastError`` is a disconnection error. Only does this
+  ## if flags contains ``SafeDisconn``.
+  when useWinVersion:
+    TSocketFlags.SafeDisconn in flags and
+      lastError.int32 in {WSAECONNRESET, WSAECONNABORTED, WSAENETRESET,
+                          WSAEDISCON}
+  else:
+    TSocketFlags.SafeDisconn in flags and
+      lastError.int32 in {ECONNRESET, EPIPE, ENETRESET} 
+
+proc toOSFlags*(socketFlags: set[TSocketFlags]): cint =
+  ## Converts the flags into the underlying OS representation.
+  for f in socketFlags:
+    case f
+    of TSocketFlags.Peek:
+      result = result or MSG_PEEK
+    of TSocketFlags.SafeDisconn: continue
+
 proc createSocket(fd: TSocketHandle, isBuff: bool): PSocket =
   assert fd != osInvalidSocket
   new(result)
@@ -470,7 +494,8 @@ when defined(ssl):
     if SSLSetFd(socket.sslHandle, socket.fd) != 1:
       SSLError()
 
-proc socketError*(socket: PSocket, err: int = -1, async = false) =
+proc socketError*(socket: PSocket, err: int = -1, async = false,
+                  lastError = (-1).TOSErrorCode) =
   ## Raises an EOS error based on the error code returned by ``SSLGetError``
   ## (for SSL sockets) and ``osLastError`` otherwise.
   ##
@@ -500,17 +525,17 @@ proc socketError*(socket: PSocket, err: int = -1, async = false) =
         else: SSLError("Unknown Error")
   
   if err == -1 and not (when defined(ssl): socket.isSSL else: false):
-    let lastError = osLastError()
+    let lastE = if lastError.int == -1: osLastError() else: lastError
     if async:
       when useWinVersion:
-        if lastError.int32 == WSAEWOULDBLOCK:
+        if lastE.int32 == WSAEWOULDBLOCK:
           return
-        else: osError(lastError)
+        else: osError(lastE)
       else:
-        if lastError.int32 == EAGAIN or lastError.int32 == EWOULDBLOCK:
+        if lastE.int32 == EAGAIN or lastE.int32 == EWOULDBLOCK:
           return
-        else: osError(lastError)
-    else: osError(lastError)
+        else: osError(lastE)
+    else: osError(lastE)
 
 proc listen*(socket: PSocket, backlog = SOMAXCONN) {.tags: [FReadIO].} =
   ## Marks ``socket`` as accepting connections. 
@@ -805,6 +830,7 @@ proc recv*(socket: PSocket, data: pointer, size: int): int {.tags: [FReadIO].} =
     
       let chunk = min(socket.bufLen-socket.currPos, size-read)
       var d = cast[cstring](data)
+      assert size-read >= chunk
       copyMem(addr(d[read]), addr(socket.buffer[socket.currPos]), chunk)
       read.inc(chunk)
       socket.currPos.inc(chunk)
@@ -871,6 +897,7 @@ proc recv*(socket: PSocket, data: pointer, size: int, timeout: int): int {.
   while read < size:
     let avail = waitFor(socket, waited, timeout, size-read, "recv")
     var d = cast[cstring](data)
+    assert avail <= size-read
     result = recv(socket, addr(d[read]), avail)
     if result == 0: break
     if result < 0:
@@ -879,7 +906,8 @@ proc recv*(socket: PSocket, data: pointer, size: int, timeout: int): int {.
   
   result = read
 
-proc recv*(socket: PSocket, data: var string, size: int, timeout = -1): int =
+proc recv*(socket: PSocket, data: var string, size: int, timeout = -1,
+           flags = {TSocketFlags.SafeDisconn}): int =
   ## Higher-level version of ``recv``.
   ##
   ## When 0 is returned the socket's connection has been closed.
@@ -891,11 +919,15 @@ proc recv*(socket: PSocket, data: var string, size: int, timeout = -1): int =
   ## within the time specified an ETimeout exception will be raised.
   ##
   ## **Note**: ``data`` must be initialised.
+  ##
+  ## **Warning**: Only the ``SafeDisconn`` flag is currently supported.
   data.setLen(size)
   result = recv(socket, cstring(data), size, timeout)
   if result < 0:
     data.setLen(0)
-    socket.socketError(result)
+    let lastError = osLastError()
+    if flags.isDisconnectionError(lastError): return
+    socket.socketError(result, lastError = lastError)
   data.setLen(result)
 
 proc peekChar(socket: PSocket, c: var char): int {.tags: [FReadIO].} =
@@ -918,7 +950,8 @@ proc peekChar(socket: PSocket, c: var char): int {.tags: [FReadIO].} =
         return
     result = recv(socket.fd, addr(c), 1, MSG_PEEK)
 
-proc readLine*(socket: PSocket, line: var TaintedString, timeout = -1) {.
+proc readLine*(socket: PSocket, line: var TaintedString, timeout = -1,
+               flags = {TSocketFlags.SafeDisconn}) {.
   tags: [FReadIO, FTime].} =
   ## Reads a line of data from ``socket``.
   ##
@@ -932,11 +965,18 @@ proc readLine*(socket: PSocket, line: var TaintedString, timeout = -1) {.
   ##
   ## A timeout can be specified in miliseconds, if data is not received within
   ## the specified time an ETimeout exception will be raised.
+  ##
+  ## **Warning**: Only the ``SafeDisconn`` flag is currently supported.
   
   template addNLIfEmpty(): stmt =
     if line.len == 0:
       line.add("\c\L")
 
+  template raiseSockError(): stmt {.dirty, immediate.} =
+    let lastError = osLastError()
+    if flags.isDisconnectionError(lastError): setLen(line.string, 0); return
+    socket.socketError(n, lastError = lastError)
+
   var waited = 0.0
 
   setLen(line.string, 0)
@@ -944,14 +984,14 @@ proc readLine*(socket: PSocket, line: var TaintedString, timeout = -1) {.
     var c: char
     discard waitFor(socket, waited, timeout, 1, "readLine")
     var n = recv(socket, addr(c), 1)
-    if n < 0: socket.socketError()
-    elif n == 0: return
+    if n < 0: raiseSockError()
+    elif n == 0: setLen(line.string, 0); return
     if c == '\r':
       discard waitFor(socket, waited, timeout, 1, "readLine")
       n = peekChar(socket, c)
       if n > 0 and c == '\L':
         discard recv(socket, addr(c), 1)
-      elif n <= 0: socket.socketError()
+      elif n <= 0: raiseSockError()
       addNLIfEmpty()
       return
     elif c == '\L': 
@@ -1019,11 +1059,14 @@ proc send*(socket: PSocket, data: pointer, size: int): int {.
       const MSG_NOSIGNAL = 0
     result = send(socket.fd, data, size, int32(MSG_NOSIGNAL))
 
-proc send*(socket: PSocket, data: string) {.tags: [FWriteIO].} =
+proc send*(socket: PSocket, data: string,
+           flags = {TSocketFlags.SafeDisconn}) {.tags: [FWriteIO].} =
   ## sends data to a socket.
   let sent = send(socket, cstring(data), data.len)
   if sent < 0:
-    socketError(socket)
+    let lastError = osLastError()
+    if flags.isDisconnectionError(lastError): return
+    socketError(socket, lastError = lastError)
 
   if sent != data.len:
     raise newException(EOS, "Could not send all data.")
diff --git a/lib/pure/nimprof.nim b/lib/pure/nimprof.nim
index 3d0cc2154..ab7cd1944 100644
--- a/lib/pure/nimprof.nim
+++ b/lib/pure/nimprof.nim
@@ -58,8 +58,9 @@ when not defined(memProfiler):
     ## instruction count measure instead then.
     if intervalInUs <= 0: interval = 0
     else: interval = intervalInUs * 1000 - tickCountCorrection
-  
+
 when withThreads:
+  import locks
   var
     profilingLock: TLock
 
@@ -72,7 +73,7 @@ proc hookAux(st: TStackTrace, costs: int) =
   var last = high(st)
   while last > 0 and isNil(st[last]): dec last
   var h = hash(pointer(st[last])) and high(profileData)
-  
+
   # we use probing for maxChainLen entries and replace the encountered entry
   # with the minimal 'total' value:
   if emptySlots == 0:
@@ -133,7 +134,7 @@ else:
       hookAux(st, 1)
     elif getticks() - t0 > interval:
       hookAux(st, 1)
-      t0 = getticks()  
+      t0 = getticks()
 
 proc getTotal(x: ptr TProfileEntry): int =
   result = if isNil(x): 0 else: x.total
@@ -145,7 +146,7 @@ proc `//`(a, b: int): string =
   result = format("$1/$2 = $3%", a, b, formatFloat(a / b * 100.0, ffDefault, 2))
 
 proc writeProfile() {.noconv.} =
-  when defined(system.TStackTrace): 
+  when defined(system.TStackTrace):
     system.profilerHook = nil
   const filename = "profile_results.txt"
   echo "writing " & filename & "..."
@@ -156,7 +157,7 @@ proc writeProfile() {.noconv.} =
     var entries = 0
     for i in 0..high(profileData):
       if profileData[i] != nil: inc entries
-    
+
     var perProc = initCountTable[string]()
     for i in 0..entries-1:
       var dups = initSet[string]()
@@ -166,7 +167,7 @@ proc writeProfile() {.noconv.} =
         let p = $procname
         if not containsOrIncl(dups, p):
           perProc.inc(p, profileData[i].total)
-    
+
     var sum = 0
     # only write the first 100 entries:
     for i in 0..min(100, entries-1):
diff --git a/lib/pure/oids.nim b/lib/pure/oids.nim
index b3e74d2a1..2843e6c65 100644
--- a/lib/pure/oids.nim
+++ b/lib/pure/oids.nim
@@ -62,9 +62,9 @@ var
 
 proc genOid*(): TOid =
   ## generates a new OID.
-  proc rand(): cint {.importc: "rand", nodecl.}
+  proc rand(): cint {.importc: "rand", header: "<stdlib.h>", nodecl.}
   proc gettime(dummy: ptr cint): cint {.importc: "time", header: "<time.h>".}
-  proc srand(seed: cint) {.importc: "srand", nodecl.}
+  proc srand(seed: cint) {.importc: "srand", header: "<stdlib.h>", nodecl.}
 
   var t = gettime(nil)
   
diff --git a/lib/pure/os.nim b/lib/pure/os.nim
index 00a33db75..0b4538abc 100644
--- a/lib/pure/os.nim
+++ b/lib/pure/os.nim
@@ -1,7 +1,7 @@
 #
 #
 #            Nimrod's Runtime Library
-#        (c) Copyright 2012 Andreas Rumpf
+#        (c) Copyright 2014 Andreas Rumpf
 #
 #    See the file "copying.txt", included in this
 #    distribution, for details about the copyright.
@@ -1612,6 +1612,20 @@ when defined(linux) or defined(solaris) or defined(bsd) or defined(aix):
       len = readlink(procPath, result, len)
     setLen(result, len)
 
+when not (defined(windows) or defined(macosx)):
+  proc getApplHeuristic(): string =
+    when defined(paramStr):
+      result = string(paramStr(0))
+      # POSIX guaranties that this contains the executable
+      # as it has been executed by the calling process
+      if len(result) > 0 and result[0] != DirSep: # not an absolute path?
+        # iterate over any path in the $PATH environment variable
+        for p in split(string(getEnv("PATH")), {PathSep}):
+          var x = joinPath(p, result)
+          if existsFile(x): return x
+    else:
+      result = ""
+
 when defined(macosx):
   type
     cuint32* {.importc: "unsigned int", nodecl.} = int
@@ -1648,10 +1662,13 @@ proc getAppFilename*(): string {.rtl, extern: "nos$1", tags: [FReadIO].} =
       setlen(result, int(len))
   elif defined(linux) or defined(aix):
     result = getApplAux("/proc/self/exe")
+    if result.len == 0: result = getApplHeuristic()
   elif defined(solaris):
     result = getApplAux("/proc/" & $getpid() & "/path/a.out")
+    if result.len == 0: result = getApplHeuristic()
   elif defined(freebsd):
     result = getApplAux("/proc/" & $getpid() & "/file")
+    if result.len == 0: result = getApplHeuristic()
   elif defined(macosx):
     var size: cuint32
     getExecPath1(nil, size)
@@ -1663,15 +1680,7 @@ proc getAppFilename*(): string {.rtl, extern: "nos$1", tags: [FReadIO].} =
   else:
     # little heuristic that may work on other POSIX-like systems:
     result = string(getEnv("_"))
-    if len(result) == 0:
-      result = string(paramStr(0))
-      # POSIX guaranties that this contains the executable
-      # as it has been executed by the calling process
-      if len(result) > 0 and result[0] != DirSep: # not an absolute path?
-        # iterate over any path in the $PATH environment variable
-        for p in split(string(getEnv("PATH")), {PathSep}):
-          var x = joinPath(p, result)
-          if existsFile(x): return x
+    if result.len == 0: result = getApplHeuristic()
 
 proc getApplicationFilename*(): string {.rtl, extern: "nos$1", deprecated.} =
   ## Returns the filename of the application's executable.
@@ -1760,16 +1769,16 @@ else:
     FileId = TIno
 
 type
-  FileInfo = object
+  FileInfo* = object
     ## Contains information associated with a file object.
-    id: tuple[device: DeviceId, file: FileId] # Device and file id.
-    kind: TPathComponent # Kind of file object - directory, symlink, etc.
-    size: BiggestInt # Size of file.
-    permissions: set[TFilePermission] # File permissions
-    linkCount: BiggestInt # Number of hard links the file object has.
-    lastAccessTime: TTime # Time file was last accessed.
-    lastWriteTime: TTime # Time file was last modified/written to.
-    creationTime: TTime # Time file was created. Not supported on all systems!
+    id*: tuple[device: DeviceId, file: FileId] # Device and file id.
+    kind*: TPathComponent # Kind of file object - directory, symlink, etc.
+    size*: BiggestInt # Size of file.
+    permissions*: set[TFilePermission] # File permissions
+    linkCount*: BiggestInt # Number of hard links the file object has.
+    lastAccessTime*: TTime # Time file was last accessed.
+    lastWriteTime*: TTime # Time file was last modified/written to.
+    creationTime*: TTime # Time file was created. Not supported on all systems!
 
 template rawToFormalFileInfo(rawInfo, formalInfo): expr =
   ## Transforms the native file info structure into the one nimrod uses.
diff --git a/lib/pure/osproc.nim b/lib/pure/osproc.nim
index 6e250f9d5..04a0c2403 100644
--- a/lib/pure/osproc.nim
+++ b/lib/pure/osproc.nim
@@ -1,7 +1,7 @@
 #
 #
 #            Nimrod's Runtime Library
-#        (c) Copyright 2013 Andreas Rumpf
+#        (c) Copyright 2014 Andreas Rumpf
 #
 #    See the file "copying.txt", included in this
 #    distribution, for details about the copyright.
@@ -13,7 +13,7 @@
 include "system/inclrtl"
 
 import
-  strutils, os, strtabs, streams
+  strutils, os, strtabs, streams, cpuinfo
 
 when defined(windows):
   import winlean
@@ -225,42 +225,10 @@ proc errorHandle*(p: PProcess): TFileHandle {.rtl, extern: "nosp$1",
   ## it is closed when closing the PProcess ``p``.
   result = p.errHandle
 
-when defined(macosx) or defined(bsd):
-  const
-    CTL_HW = 6
-    HW_AVAILCPU = 25
-    HW_NCPU = 3
-  proc sysctl(x: ptr array[0..3, cint], y: cint, z: pointer,
-              a: var csize, b: pointer, c: int): cint {.
-             importc: "sysctl", header: "<sys/sysctl.h>".}
-
 proc countProcessors*(): int {.rtl, extern: "nosp$1".} =
   ## returns the numer of the processors/cores the machine has.
   ## Returns 0 if it cannot be detected.
-  when defined(windows):
-    var x = getEnv("NUMBER_OF_PROCESSORS")
-    if x.len > 0: result = parseInt(x.string)
-  elif defined(macosx) or defined(bsd):
-    var
-      mib: array[0..3, cint]
-      numCPU: int
-      len: csize
-    mib[0] = CTL_HW
-    mib[1] = HW_AVAILCPU
-    len = sizeof(numCPU)
-    discard sysctl(addr(mib), 2, addr(numCPU), len, nil, 0)
-    if numCPU < 1:
-      mib[1] = HW_NCPU
-      discard sysctl(addr(mib), 2, addr(numCPU), len, nil, 0)
-    result = numCPU
-  elif defined(hpux):
-    result = mpctl(MPC_GETNUMSPUS, nil, nil)
-  elif defined(irix):
-    var SC_NPROC_ONLN {.importc: "_SC_NPROC_ONLN", header: "<unistd.h>".}: cint
-    result = sysconf(SC_NPROC_ONLN)
-  else:
-    result = sysconf(SC_NPROCESSORS_ONLN)
-  if result <= 0: result = 1
+  result = cpuinfo.countProcessors()
 
 proc execProcesses*(cmds: openArray[string],
                     options = {poStdErrToStdOut, poParentStreams},
@@ -800,8 +768,8 @@ elif not defined(useNimRtl):
 
   proc startProcessAfterFork(data: ptr TStartProcessData) =
     # Warning: no GC here!
-    # Or anythink that touches global structures - all called nimrod procs
-    # must be marked with noStackFrame. Inspect C code after making changes.
+    # Or anything that touches global structures - all called nimrod procs
+    # must be marked with stackTrace:off. Inspect C code after making changes.
     if not data.optionPoParentStreams:
       discard close(data.pStdin[writeIdx])
       if dup2(data.pStdin[readIdx], readIdx) < 0:
@@ -903,7 +871,7 @@ elif not defined(useNimRtl):
       createStream(p.errStream, p.errHandle, fmRead)
     return p.errStream
 
-  proc csystem(cmd: cstring): cint {.nodecl, importc: "system".}
+  proc csystem(cmd: cstring): cint {.nodecl, importc: "system", header: "<stdlib.h>".}
 
   proc execCmd(command: string): int =
     when defined(linux):
diff --git a/lib/pure/rawsockets.nim b/lib/pure/rawsockets.nim
index 07b647b68..d96741846 100644
--- a/lib/pure/rawsockets.nim
+++ b/lib/pure/rawsockets.nim
@@ -21,11 +21,12 @@ const useWinVersion = defined(Windows) or defined(nimdoc)
 
 when useWinVersion:
   import winlean
-  export WSAEWOULDBLOCK
+  export WSAEWOULDBLOCK, WSAECONNRESET, WSAECONNABORTED, WSAENETRESET,
+         WSAEDISCON
 else:
   import posix
   export fcntl, F_GETFL, O_NONBLOCK, F_SETFL, EAGAIN, EWOULDBLOCK, MSG_NOSIGNAL,
-    EINTR, EINPROGRESS
+    EINTR, EINPROGRESS, ECONNRESET, EPIPE, ENETRESET
 
 export TSocketHandle, TSockaddr_in, TAddrinfo, INADDR_ANY, TSockAddr, TSockLen,
   inet_ntoa, recv, `==`, connect, send, accept, recvfrom, sendto
@@ -39,7 +40,6 @@ export
   MSG_PEEK
 
 type
-  
   TPort* = distinct uint16  ## port type
   
   TDomain* = enum   ## domain, which specifies the protocol family of the
diff --git a/lib/pure/selectors.nim b/lib/pure/selectors.nim
index f630ba235..bd53c2dbf 100644
--- a/lib/pure/selectors.nim
+++ b/lib/pure/selectors.nim
@@ -11,9 +11,12 @@
 
 import tables, os, unsigned, hashes
 
-when defined(linux): import posix, epoll
-elif defined(windows): import winlean
-else: import posix
+when defined(linux): 
+  import posix, epoll
+elif defined(windows): 
+  import winlean
+else: 
+  import posix
 
 proc hash*(x: TSocketHandle): THash {.borrow.}
 proc `$`*(x: TSocketHandle): string {.borrow.}
@@ -29,7 +32,36 @@ type
 
   TReadyInfo* = tuple[key: PSelectorKey, events: set[TEvent]]
 
-when defined(linux) or defined(nimdoc):
+when defined(nimdoc):
+  type
+    PSelector* = ref object
+      ## An object which holds file descripters to be checked for read/write
+      ## status.
+      fds: TTable[TSocketHandle, PSelectorKey]
+
+  proc register*(s: PSelector, fd: TSocketHandle, events: set[TEvent],
+                 data: PObject): PSelectorKey {.discardable.} =
+    ## Registers file descriptor ``fd`` to selector ``s`` with a set of TEvent
+    ## ``events``.
+
+  proc update*(s: PSelector, fd: TSocketHandle,
+               events: set[TEvent]): PSelectorKey {.discardable.} =
+    ## Updates the events which ``fd`` wants notifications for.
+
+  proc select*(s: PSelector, timeout: int): seq[TReadyInfo] =
+    ## The ``events`` field of the returned ``key`` contains the original events
+    ## for which the ``fd`` was bound. This is contrary to the ``events`` field
+    ## of the ``TReadyInfo`` tuple which determines which events are ready
+    ## on the ``fd``.
+
+  proc contains*(s: PSelector, fd: TSocketHandle): bool =
+    ## Determines whether selector contains a file descriptor.
+
+  proc `[]`*(s: PSelector, fd: TSocketHandle): PSelectorKey =
+    ## Retrieves the selector key for ``fd``.
+
+
+elif defined(linux):
   type
     PSelector* = ref object
       epollFD: cint
@@ -49,9 +81,10 @@ when defined(linux) or defined(nimdoc):
     ## Registers file descriptor ``fd`` to selector ``s`` with a set of TEvent
     ## ``events``.
     var event = createEventStruct(events, fd)
-    if epoll_ctl(s.epollFD, EPOLL_CTL_ADD, fd, addr(event)) != 0:
-      OSError(OSLastError())
-  
+    if events != {}:
+      if epoll_ctl(s.epollFD, EPOLL_CTL_ADD, fd, addr(event)) != 0:
+        OSError(OSLastError())
+
     var key = PSelectorKey(fd: fd, events: events, data: data)
   
     s.fds[fd] = key
@@ -61,11 +94,27 @@ when defined(linux) or defined(nimdoc):
       events: set[TEvent]): PSelectorKey {.discardable.} =
     ## Updates the events which ``fd`` wants notifications for.
     if s.fds[fd].events != events:
-      var event = createEventStruct(events, fd)
+      if events == {}:
+        # This fd is idle -- it should not be registered to epoll.
+        # But it should remain a part of this selector instance.
+        # This is to prevent epoll_wait from returning immediately
+        # because its got fds which are waiting for no events and
+        # are therefore constantly ready. (leading to 100% CPU usage).
+        if epoll_ctl(s.epollFD, EPOLL_CTL_DEL, fd, nil) != 0:
+          OSError(OSLastError())
+        s.fds[fd].events = events
+      else:
+        var event = createEventStruct(events, fd)
+        if s.fds[fd].events == {}:
+          # This fd is idle. It's not a member of this epoll instance and must
+          # be re-registered.
+          if epoll_ctl(s.epollFD, EPOLL_CTL_ADD, fd, addr(event)) != 0:
+            OSError(OSLastError())
+        else:
+          if epoll_ctl(s.epollFD, EPOLL_CTL_MOD, fd, addr(event)) != 0:
+            OSError(OSLastError())
+        s.fds[fd].events = events
       
-      s.fds[fd].events = events
-      if epoll_ctl(s.epollFD, EPOLL_CTL_MOD, fd, addr(event)) != 0:
-        OSError(OSLastError())
       result = s.fds[fd]
   
   proc unregister*(s: PSelector, fd: TSocketHandle): PSelectorKey {.discardable.} =
@@ -114,7 +163,7 @@ when defined(linux) or defined(nimdoc):
   proc newSelector*(): PSelector =
     new result
     result.epollFD = epoll_create(64)
-    result.events = cast[array[64, epoll_event]](alloc0(sizeof(epoll_event)*64))
+    #result.events = cast[array[64, epoll_event]](alloc0(sizeof(epoll_event)*64))
     result.fds = initTable[TSocketHandle, PSelectorKey]()
     if result.epollFD < 0:
       OSError(OSLastError())
@@ -123,7 +172,10 @@ when defined(linux) or defined(nimdoc):
     ## Determines whether selector contains a file descriptor.
     if s.fds.hasKey(fd):
       # Ensure the underlying epoll instance still contains this fd.
-      result = epollHasFd(s, fd)
+      if s.fds[fd].events != {}:
+        result = epollHasFd(s, fd)
+      else:
+        result = true
     else:
       return false
 
@@ -131,7 +183,7 @@ when defined(linux) or defined(nimdoc):
     ## Retrieves the selector key for ``fd``.
     return s.fds[fd]
 
-else:
+elif not defined(nimdoc):
   # TODO: kqueue for bsd/mac os x.
   type
     PSelector* = ref object
@@ -230,7 +282,7 @@ proc contains*(s: PSelector, key: PSelectorKey): bool =
   ## the new one may have the same value.
   return key.fd in s and s.fds[key.fd] == key
 
-when isMainModule:
+when isMainModule and not defined(nimdoc):
   # Select()
   import sockets
   type
diff --git a/lib/pure/sockets.nim b/lib/pure/sockets.nim
index 8d96cbaaf..7b8b3d557 100644
--- a/lib/pure/sockets.nim
+++ b/lib/pure/sockets.nim
@@ -295,7 +295,7 @@ when defined(ssl):
     of protSSLv23:
       newCTX = SSL_CTX_new(SSLv23_method()) # SSlv2,3 and TLS1 support.
     of protSSLv2:
-      when not defined(linux):
+      when not defined(linux) and not defined(OpenBSD):
         newCTX = SSL_CTX_new(SSLv2_method())
       else:
         SSLError()
diff --git a/lib/pure/strutils.nim b/lib/pure/strutils.nim
index bd6814dcc..e642f6a99 100644
--- a/lib/pure/strutils.nim
+++ b/lib/pure/strutils.nim
@@ -10,6 +10,8 @@
 ## This module contains various string utility routines.
 ## See the module `re <re.html>`_ for regular expression support.
 ## See the module `pegs <pegs.html>`_ for PEG support.
+## This module is available for the `JavaScript target
+## <backends.html#the-javascript-target>`_.
 
 import parseutils
 
diff --git a/lib/pure/times.nim b/lib/pure/times.nim
index fdff06b2a..498511899 100644
--- a/lib/pure/times.nim
+++ b/lib/pure/times.nim
@@ -9,7 +9,8 @@
 
 
 ## This module contains routines and types for dealing with time.
-## This module is available for the JavaScript target.
+## This module is available for the `JavaScript target
+## <backends.html#the-javascript-target>`_.
 
 {.push debugger:off.} # the user does not want to trace a part
                       # of the standard library!