1 files changed, 70 insertions, 0 deletions
diff --git a/cpp/037call_reply b/cpp/037call_reply
new file mode 100644
index 00000000..b44552cc
--- /dev/null
+++ b/cpp/037call_reply
@@ -0,0 +1,70 @@
+//: Calls can also generate results, using 'reply'.
+:(scenario "reply")
+recipe main [
+  3:integer, 4:integer <- f 2:literal
+]
+recipe f [
+  12:integer <- next-ingredient
+  13:integer <- add 1:literal, 12:integer
+  reply 12:integer, 13:integer
+]
++run: instruction main/0
++run: result 0 is 2
++mem: storing 2 in location 3
++run: result 1 is 3
++mem: storing 3 in location 4
+
+:(before "End Primitive Recipe Declarations")
+REPLY,
+:(before "End Primitive Recipe Numbers")
+Recipe_number["reply"] = REPLY;
+:(before "End Primitive Recipe Implementations")
+case REPLY: {
+  vector<vector<int> > callee_results;
+  for (size_t i = 0; i < instructions[pc].ingredients.size(); ++i) {
+    callee_results.push_back(read_memory(instructions[pc].ingredients[i]));
+  }
+  rr.calls.pop();
+  assert(!rr.calls.empty());
+  size_t& caller_pc = rr.calls.top().pc;
+  instruction& caller_instruction = Recipe[rr.calls.top().running_recipe].steps[caller_pc];
+  assert(caller_instruction.products.size() <= callee_results.size());
+  for (size_t i = 0; i < caller_instruction.products.size(); ++i) {
+    trace("run") << "result " << i << " is " << to_string(callee_results[i]);
+    write_memory(caller_instruction.products[i], callee_results[i]);
+  }
+  ++caller_pc;
+  break;
+}
+
+//: Results can include containers and exclusive containers, addresses and arrays.
+:(scenario "reply_container")
+recipe main [
+  3:point <- f 2:literal
+]
+recipe f [
+  12:integer <- next-ingredient
+  13:integer <- copy 35:literal
+  reply 12:point
+]
++run: instruction main/0
++run: result 0 is [2, 35]
++mem: storing 2 in location 3
++mem: storing 35 in location 4
+
+:(code)
+string to_string(const vector<int>& in) {
+  if (in.empty()) return "[]";
+  ostringstream out;
+  if (in.size() == 1) {
+    out << in[0];
+    return out.str();
+  }
+  out << "[";
+  for (size_t i = 0; i < in.size(); ++i) {
+    if (i > 0) out << ", ";
+    out << in[i];
+  }
+  out << "]";
+  return out.str();
+}