clean up concurrency example

examples/concurrency.cc

@@ -3,38 +3,31 @@
 
 using namespace ostd;
 
-template<typename S>
-void foo(S &sched) {
-    auto arr = ostd::iter({ 150, 38, 76, 25, 67, 18, -15, -38, 25, -10 });
-
-    auto h1 = arr.slice(0, arr.size() / 2);
-    auto h2 = arr.slice(arr.size() / 2, arr.size());
-
-    auto c = sched.template make_channel<int>();
-    auto f = [](auto c, auto half) {
-        c.put(foldl(half, 0));
-    };
-    sched.spawn(f, c, h1);
-    sched.spawn(f, c, h2);
-
-    int a, b;
-    c.get(a);
-    c.get(b);
-    writefln("first half: %s", a);
-    writefln("second half: %s", b);
-    writefln("total: %s", a + b);
-}
-
 int main() {
+    auto foo = [](auto &sched) {
+        auto arr = ostd::iter({ 150, 38, 76, 25, 67, 18, -15,  215, 25, -10 });
+
+        auto c = sched.template make_channel<int>();
+        auto f = [](auto c, auto half) {
+            c.put(foldl(half, 0));
+        };
+        sched.spawn(f, c, arr.slice(0, arr.size() / 2));
+        sched.spawn(f, c, arr.slice(arr.size() / 2, arr.size()));
+
+        int a, b;
+        c.get(a), c.get(b);
+        writefln("%s + %s = %s", a, b, a + b);
+    };
+
     thread_scheduler tsched;
-    tsched.start([&tsched]() {
+    tsched.start([&tsched, &foo]() {
         writeln("thread scheduler: starting...");
         foo(tsched);
         writeln("thread scheduler: finishing...");
     });
 
     simple_coroutine_scheduler scsched;
-    scsched.start([&scsched]() {
+    scsched.start([&scsched, &foo]() {
         writeln("simple coroutine scheduler: starting...");
         foo(scsched);
         writeln("simple coroutine scheduler: finishing...");
@@ -43,13 +36,9 @@ int main() {
 
 /*
 thread scheduler: starting...
-first half: 356
+356 + 233 = 589
-second half: -20
-total: 336
 thread scheduler: finishing...
 simple coroutine scheduler: starting...
-first half: 356
+356 + 233 = 589
-second half: -20
-total: 336
 simple coroutine scheduler: finishing...
 */