closure implementation: first steps

todo.txt

@@ -1,8 +1,9 @@
 version 0.8.14
 ==============
 
-- bug: tsortdev does not run with native GC?
+- implement closures
 - object {.pure, final.} does not work again!
+- bug: tsortdev does not run with native GC?
 - ``=`` should be overloadable; requires specialization for ``=``?
 
 version 0.9.0
@@ -18,7 +19,7 @@ version 0.9.0
   use tyInt+node for that
 - implement the high level optimizer
 - change overloading resolution
-- implement closures; implement proper coroutines
+- implement proper coroutines
 - implement ``partial`` pragma for partial evaluation
 - we need to support iteration of 2 different data structures in parallel
 - make exceptions compatible with C++ exceptions
@@ -56,6 +57,11 @@ version 0.9.XX
 - implicit ref/ptr->var conversion; the compiler may store an object
   implicitly on the heap for write barrier efficiency; better: 
   proc specialization in the code gen
+- shared memory heap: ``shared ref`` etc. The only hard part in the GC is to
+  "stop the world". However, it may be worthwhile to generate explicit 
+  (or implicit) syncGC() calls in loops. Automatic loop injection seems
+  troublesome, but maybe we can come up with a simple heuristic. (All procs
+  that `new` shared memory are syncGC() candidates...)
 - EcmaScript needs a new and better code gen: simply adapt the C code gen to it
 - tlastmod returns wrong results on BSD (Linux, MacOS X: works)
 - nested tuple unpacking; tuple unpacking in non-var-context