Some code cleanup, removed unused functions, changed == empty-list to isNil to avoid unnecessary construction of empty lists, replaced some casts by generic declarations. Added simple maybe, failable and state monad classes to help return optional objects or failures and carry state around. Added utility functions to zip and unzip list.

git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@823981 13f79535-47bb-0310-9956-ffa450edef68

1 files changed, 3 insertions, 3 deletions

diff --git a/cpp/sca/kernel/parallel.hpp b/cpp/sca/kernel/parallel.hpp
index 82983d9edc..07d1471152 100644
--- a/cpp/sca/kernel/parallel.hpp
+++ b/cpp/sca/kernel/parallel.hpp
@@ -254,9 +254,9 @@ template<typename R> const future<R> submit(worker& w, const lambda<R()>& func)
  * Enqueues shutdown requests.
  */
 const bool shutdownEnqueue(const list<pthread_t>& threads, queue<lambda<bool()> >& work) {
-    if (threads == list<pthread_t>())
+    if (isNil(threads))
         return true;
-    enqueue(work, unit(false));
+    enqueue(work, result(false));
     return shutdownEnqueue(cdr(threads), work);
 }
 
@@ -264,7 +264,7 @@ const bool shutdownEnqueue(const list<pthread_t>& threads, queue<lambda<bool()>
  * Waits for shut down threads to terminate.
  */
 const bool shutdownJoin(const list<pthread_t>& threads) {
-    if (threads == list<pthread_t>())
+    if (isNil(threads))
         return true;
     pthread_join(car(threads), NULL);
     return shutdownJoin(cdr(threads));