Execute function nodes as parallel tasks.

lib/pls/include/pls/dataflow/internal/build_state.h

+
+#ifndef PLS_DATAFLOW_INTERNAL_BUILD_STATE_H_
+#define PLS_DATAFLOW_INTERNAL_BUILD_STATE_H_
+
+namespace pls {
+namespace dataflow {
+namespace internal {
+
+enum class build_state { fresh, building, built, teardown };
+
+}
+}
+}
+
+#endif //PLS_DATAFLOW_INTERNAL_BUILD_STATE_H_

lib/pls/include/pls/dataflow/internal/function_node.h

@@ -14,6 +14,7 @@
 #include "outputs.h"
 
 #include "pls/internal/helpers/seqence.h"
+#include "pls/pls.h"
 
 namespace pls {
 namespace dataflow {
@@ -75,12 +76,15 @@ class function_node<pls::dataflow::inputs<I0, I...>, pls::dataflow::outputs<O0,
   }
 
   void execute_function(invocation_memory *invocation_memory, invocation_info invocation_info) {
-    input_tuple &inputs = invocation_memory->input_buffer_;
-    output_tuple outputs;
-
-    execute_function_internal(inputs, typename sequence_gen<1 + sizeof...(I)>::type(),
-                              outputs, typename sequence_gen<1 + sizeof...(O)>::type(), invocation_info);
-
+    auto lambda = [&]() {
+      input_tuple &inputs = invocation_memory->input_buffer_;
+      output_tuple outputs;
+
+      execute_function_internal(inputs, typename sequence_gen<1 + sizeof...(I)>::type(),
+                                outputs, typename sequence_gen<1 + sizeof...(O)>::type(), invocation_info);
+    };
+    // TODO: maybe replace this with 'continuation' style invocation
+    pls::scheduler::spawn_child_and_wait<pls::lambda_task_by_reference<decltype(lambda)>>(lambda);
   }
   template<typename T>
   void set_invocation_info(token<T> &token, invocation_info invocation_info) {