Add multithreading support

.gitignore

@@ -15,6 +15,10 @@ Test.dll
 Test.dll.so
 Test.cs
 Test_ast.store
+Threads.dll
+Threads.dll.so
+Threads.cs
+Threads_ast.store
 MONKEY_TYPING.dll
 MONKEY_TYPING.dll.so
 MONKEY_TYPING.cs

Kernel.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Threading;
 namespace Niecza {
     // We like to reuse continuation objects for speed - every function only
     // creates one kind of continuation, but tweaks a field for exact return
@@ -780,6 +781,25 @@ public class Kernel {
             }
         }
 
+        public static Frame StartP6Thread(Frame th, IP6 sub) {
+            Thread thr = new Thread(delegate () {
+                    Frame current = sub.Invoke(th, new Variable[0], null);
+
+                    while (current != th) {
+                        try {
+                            current = current.Continue();
+                        } catch (Exception ex) {
+                            ExceptionPacket ep = new FatalException(
+                                    new CLRImportObject(ex));
+                            current = ep.SearchForHandler(current);
+                        }
+                    }
+                });
+            thr.Start();
+            th.resultSlot = thr;
+            return th;
+        }
+
         public static void RunLoop(DynBlockDelegate boot) {
             Kernel.TraceCont = (Environment.GetEnvironmentVariable("NIECZA_TRACE") != null);
             Frame root_f = new Frame(null, null, boot);

Threads.pm6

@@ -0,0 +1,35 @@
+module Threads;
+
+# Should be a role, since it can be applied to any class with minimal overhead
+class Monitor is export {
+    method enter() {
+        Q:CgOp {
+            (prog (rawscall System.Threading.Monitor.Enter:m,Void
+                (@ (l self))) (null Variable))
+        }
+    }
+    method exit() {
+        Q:CgOp {
+            (prog (rawscall System.Threading.Monitor.Exit:m,Void
+                (@ (l self))) (null Variable))
+        }
+    }
+    # TODO exception handling
+    method lock($f) { self.enter; $f(); self.exit }
+}
+
+class Thread is export {
+    method new($func) {
+        Q:CgOp { (box Thread (rawsccall
+            Kernel.StartP6Thread:c,System.Threading.Thread (@ (l $func)))) }
+    }
+
+    method join() {
+        Q:CgOp { (prog (rawcall (unbox System.Threading.Thread (@ (l self))) Join:m,Void) (null Variable)) }
+    }
+
+    method sleep($time) {
+        my $t = $time * 1000;
+        Q:CgOp { (prog (rawscall System.Threading.Thread.Sleep:m,Void (cast Int32 (unbox Double (@ (l $t))))) (null Variable)) }
+    }
+}