1 files changed, 158 insertions, 0 deletions
diff --git a/036call_reply.cc b/036call_reply.cc
new file mode 100644
index 00000000..8c69fa3f
--- /dev/null
+++ b/036call_reply.cc
@@ -0,0 +1,158 @@
+//: Calls can also generate products, using 'reply'.
+
+:(scenario reply)
+recipe main [
+  1:number, 2:number <- f 34:literal
+]
+recipe f [
+  12:number <- next-ingredient
+  13:number <- add 1:literal, 12:number
+  reply 12:number, 13:number
+]
++mem: storing 34 in location 1
++mem: storing 35 in location 2
+
+:(before "End Primitive Recipe Declarations")
+REPLY,
+:(before "End Primitive Recipe Numbers")
+Recipe_number["reply"] = REPLY;
+:(before "End Primitive Recipe Implementations")
+case REPLY: {
+  const instruction& reply_inst = current_instruction();  // save pointer into recipe before pop
+  const string& callee = current_recipe_name();
+  --Callstack_depth;
+//?   if (tb_is_active()) { //? 1
+//?     tb_clear(); //? 1
+//?     cerr << Recipe[Current_routine->calls.front().running_recipe].name << ' ' << current_step_index() << '\n'; //? 1
+//?   } //? 1
+  Current_routine->calls.pop_front();
+  // just in case 'main' returns a value, drop it for now
+  if (Current_routine->calls.empty()) goto stop_running_current_routine;
+  const instruction& caller_instruction = current_instruction();
+  // make reply results available to caller
+  copy(ingredients.begin(), ingredients.end(), inserter(products, products.begin()));
+  // check that any reply ingredients with /same-as-ingredient connect up
+  // the corresponding ingredient and product in the caller.
+  for (long long int i = 0; i < SIZE(caller_instruction.products); ++i) {
+//?     cerr << Recipe[Current_routine->calls.front().running_recipe].name << '\n'; //? 1
+    trace(Primitive_recipe_depth, "run") << "result " << i << " is " << to_string(ingredients.at(i));
+    if (has_property(reply_inst.ingredients.at(i), "same-as-ingredient")) {
+      vector<string> tmp = property(reply_inst.ingredients.at(i), "same-as-ingredient");
+      assert(SIZE(tmp) == 1);
+      long long int ingredient_index = to_integer(tmp.at(0));
+      if (caller_instruction.products.at(i).value != caller_instruction.ingredients.at(ingredient_index).value)
+        raise << current_recipe_name() << ": 'same-as-ingredient' result " << caller_instruction.products.at(i).value << " from call to " << callee << " must be location " << caller_instruction.ingredients.at(ingredient_index).value << '\n';
+    }
+  }
+  break;  // continue to process rest of *caller* instruction
+}
+
+//: Products can include containers and exclusive containers, addresses and arrays.
+:(scenario reply_container)
+recipe main [
+  3:point <- f 2:literal
+]
+recipe f [
+  12:number <- next-ingredient
+  13:number <- copy 35:literal
+  reply 12:point/raw  # unsafe
+]
++run: result 0 is [2, 35]
++mem: storing 2 in location 3
++mem: storing 35 in location 4
+
+//: In mu we'd like to assume that any instruction doesn't modify its
+//: ingredients unless they're also products. The /same-as-ingredient inside
+//: the recipe's 'reply' will help catch accidental misuse of such
+//: 'ingredient-results' (sometimes called in-out parameters in other languages).
+
+:(scenario reply_same_as_ingredient)
+% Hide_warnings = true;
+recipe main [
+  1:number <- copy 0:literal
+  2:number <- test1 1:number  # call with different ingredient and product
+]
+recipe test1 [
+  10:address:number <- next-ingredient
+  reply 10:address:number/same-as-ingredient:0
+]
++warn: main: 'same-as-ingredient' result 2 from call to test1 must be location 1
+
+:(code)
+string to_string(const vector<double>& in) {
+  if (in.empty()) return "[]";
+  ostringstream out;
+  if (SIZE(in) == 1) {
+    out << in.at(0);
+    return out.str();
+  }
+  out << "[";
+  for (long long int i = 0; i < SIZE(in); ++i) {
+    if (i > 0) out << ", ";
+    out << in.at(i);
+  }
+  out << "]";
+  return out.str();
+}
+
+//: Conditional reply.
+
+:(scenario reply_if)
+recipe main [
+  1:number <- test1
+]
+recipe test1 [
+  reply-if 0:literal, 34:literal
+  reply 35:literal
+]
++mem: storing 35 in location 1
+
+:(scenario reply_if2)
+recipe main [
+  1:number <- test1
+]
+recipe test1 [
+  reply-if 1:literal, 34:literal
+  reply 35:literal
+]
++mem: storing 34 in location 1
+
+:(before "End Rewrite Instruction(curr)")
+// rewrite `reply-if a, b, c, ...` to
+//   ```
+//   jump-unless a, 1:offset
+//   reply b, c, ...
+//   ```
+if (curr.name == "reply-if") {
+  assert(curr.products.empty());
+  curr.operation = Recipe_number["jump-unless"];
+  curr.name = "jump-unless";
+  vector<reagent> results;
+  copy(++curr.ingredients.begin(), curr.ingredients.end(), inserter(results, results.end()));
+  curr.ingredients.resize(1);
+  curr.ingredients.push_back(reagent("1:offset"));
+  result.steps.push_back(curr);
+  curr.clear();
+  curr.operation = Recipe_number["reply"];
+  curr.name = "reply";
+  curr.ingredients.swap(results);
+}
+// rewrite `reply-unless a, b, c, ...` to
+//   ```
+//   jump-if a, 1:offset
+//   reply b, c, ...
+//   ```
+if (curr.name == "reply-unless") {
+  assert(curr.products.empty());
+  curr.operation = Recipe_number["jump-if"];
+  curr.name = "jump-if";
+  vector<reagent> results;
+  copy(++curr.ingredients.begin(), curr.ingredients.end(), inserter(results, results.end()));
+  curr.ingredients.resize(1);
+  curr.ingredients.push_back(reagent("1:offset"));
+  result.steps.push_back(curr);
+  curr.clear();
+  curr.operation = Recipe_number["reply"];
+  curr.name = "reply";
+  curr.ingredients.swap(results);
+}