Restructure to allow a clean interface for end users.

We need some tricks in template programming to have a clean user facing API while internally using our classes with more capabilities.

app/playground/main.cpp

 // Headers are available because we added the pls target
 #include <string>
-
 #include <cstdio>
+#include <tuple>
 
 #include <pls/pls.h>
-#include <pls/dataflow/inputs.h>
-#include <pls/dataflow/outputs.h>
+#include <pls/dataflow/graph.h>
 
 int main() {
-  pls::dataflow::inputs<int, std::string> in;
-  pls::dataflow::outputs<int> out1;
-  pls::dataflow::outputs<std::string> out2;
+  using namespace pls::dataflow;
 
-  out1.get<0>().connect(in.get<0>());
-  out2.get<0>().connect(in.get<1>());
+  graph<inputs<int>, outputs<int, int>, 8> graph;
 }

lib/pls/CMakeLists.txt

@@ -10,12 +10,12 @@ add_library(pls STATIC
         include/pls/algorithms/scan_impl.h
 
         include/pls/dataflow/dataflow.h
-        include/pls/dataflow/token.h
+        include/pls/dataflow/internal/token.h
         include/pls/dataflow/graph.h
-        include/pls/dataflow/inputs.h
-        include/pls/dataflow/outputs.h
-        include/pls/dataflow/input.h
-        include/pls/dataflow/output.h
+        include/pls/dataflow/internal/inputs.h
+        include/pls/dataflow/internal/outputs.h
+        include/pls/dataflow/internal/input.h
+        include/pls/dataflow/internal/output.h
 
         include/pls/internal/base/spin_lock.h
         include/pls/internal/base/tas_spin_lock.h src/internal/base/tas_spin_lock.cpp
@@ -47,7 +47,7 @@ add_library(pls STATIC
         include/pls/internal/scheduling/scheduler_impl.h
         include/pls/internal/scheduling/task.h src/internal/scheduling/task.cpp
         include/pls/internal/scheduling/scheduler_memory.h src/internal/scheduling/scheduler_memory.cpp
-        include/pls/internal/scheduling/lambda_task.h)
+        include/pls/internal/scheduling/lambda_task.h include/pls/dataflow/inputs.h include/pls/dataflow/outputs.h)
 # Add everything in `./include` to be in the include path of this project
 target_include_directories(pls
         PUBLIC

lib/pls/include/pls/dataflow/graph.h

@@ -2,14 +2,17 @@
 #ifndef PLS_DATAFLOW_GRAPH_H_
 #define PLS_DATAFLOW_GRAPH_H_
 
+#include "inputs.h"
+#include "outputs.h"
+
 namespace pls {
 namespace dataflow {
 
-template<
+template<typename I, typename O, int P>
 class graph {
-
+  using internal_inputs = typename I::template internal_inputs<P>;
+  using internal_outputs = typename O::template internal_outputs<P>;
 };
-
 }
 }
 

lib/pls/include/pls/dataflow/inputs.h

@@ -4,21 +4,15 @@
 
 #include <tuple>
 
-#include "input.h"
+#include "internal/inputs.h"
 
 namespace pls {
 namespace dataflow {
 
 template<typename I1, typename ...I>
-class inputs {
-  using values_type = std::tuple<input<I1>, input<I>...>;
-  values_type values_;
-
- public:
-  template<int N>
-  typename std::tuple_element<N, values_type>::type &get() {
-    return std::get<N>(values_);
-  }
+struct inputs {
+  template<int P>
+  using internal_inputs = internal::inputs<P, I1, I...>;
 };
 
 }

lib/pls/include/pls/dataflow/input.h → lib/pls/include/pls/dataflow/internal/input.h

 
-#ifndef PLS_DATAFLOW_INPUT_H_
-#define PLS_DATAFLOW_INPUT_H_
+#ifndef PLS_DATAFLOW_INTERNAL_INPUT_H_
+#define PLS_DATAFLOW_INTERNAL_INPUT_H_
 
 #include "token.h"
 
@@ -8,6 +8,7 @@
 
 namespace pls {
 namespace dataflow {
+namespace internal {
 
 template<typename T>
 class input {
@@ -26,16 +27,19 @@ class input {
     connected_ = true;
   }
 
- public:
   input() : filled_{false}, connected_{false} {};
 
-  bool has_token(color color) const {
+  bool has_token(token_color color) const {
     return filled_ && token_.color() == color;
   }
   const token<T> &get_token() const { return token_; }
+
+ public:
+
 };
 
 }
 }
+}
 
-#endif //PLS_DATAFLOW_INPUT_H_
+#endif //PLS_DATAFLOW_INTERNAL_INPUT_H_

lib/pls/include/pls/dataflow/output.h → lib/pls/include/pls/dataflow/internal/output.h

 
-#ifndef PLS_DATAFLOW_OUTPUT_H_
-#define PLS_DATAFLOW_OUTPUT_H_
+#ifndef PLS_DATAFLOW_INTERNAL_OUTPUT_H_
+#define PLS_DATAFLOW_INTERNAL_OUTPUT_H_
 
 #include "token.h"
 #include "input.h"
@@ -9,6 +9,7 @@
 
 namespace pls {
 namespace dataflow {
+namespace internal {
 
 template<typename T>
 class output {
@@ -31,5 +32,6 @@ class output {
 
 }
 }
+}
 
-#endif //PLS_DATAFLOW_OUTPUT_H_
+#endif //PLS_DATAFLOW_INTERNAL_OUTPUT_H_

lib/pls/include/pls/dataflow/token.h → lib/pls/include/pls/dataflow/internal/token.h

 
-#ifndef PLS_DATAFLOW_TOKEN_H_
-#define PLS_DATAFLOW_TOKEN_H_
+#ifndef PLS_DATAFLOW_INTERNAL_TOKEN_H_
+#define PLS_DATAFLOW_INTERNAL_TOKEN_H_
 
 namespace pls {
 namespace dataflow {
+namespace internal {
 
 /**
  * Parallel invocations of the same sub-graph are usually working with some kind of coloring
  * for tokens to distinguishe different invocations. As this concept is abstract and we could
  * change it in the future (for e.g. more advanced features/dataflows) we encapsulate it.
  */
-struct color {
+struct token_color {
   unsigned int clock_;
 };
 
 template<typename T>
 class token {
   T value_;
-  color color_;
+  token_color color_;
 
  public:
   T value() const { return value_; }
-  color color() const { return color_; }
+  token_color color() const { return color_; }
 };
 
 }
 }
+}
 
-#endif //PLS_DATAFLOW_TOKEN_H_
+#endif //PLS_DATAFLOW_INTERNAL_TOKEN_H_

lib/pls/include/pls/dataflow/outputs.h

@@ -2,23 +2,16 @@
 #ifndef PLS_DATAFLOW_OUTPUTS_H_
 #define PLS_DATAFLOW_OUTPUTS_H_
 
-#include <tuple>
-
-#include "output.h"
+#include "internal/outputs.h"
+#include "outputs.h"
 
 namespace pls {
 namespace dataflow {
 
 template<typename O1, typename ...O>
-class outputs {
-  using values_type = std::tuple<output<O1>, output<O>...>;
-  values_type values_;
-
- public:
-  template<int N>
-  typename std::tuple_element<N, values_type>::type &get() {
-    return std::get<N>(values_);
-  }
+struct outputs {
+  template<int P>
+  using internal_outputs = internal::outputs<P, O1, O...>;
 };
 
 }