path: root/cpp/054closure_name

//: Writing to a literal (not computed) address of 0 in a recipe chains two
//: spaces together. When a variable has a property of /space:1, it looks up
//: the variable in the chained/surrounding space. /space:2 looks up the
//: surrounding space of the surrounding space, etc.

:(scenario "closure")
recipe main [
  default-space:address:space <- new location:type, 30:literal
  1:address:space/names:init-counter <- init-counter
#?   $print [AAAAAAAAAAAAAAAA]
#?   $print 1:address:space
  2:integer/raw <- increment-counter 1:address:space/names:init-counter
  3:integer/raw <- increment-counter 1:address:space/names:init-counter
]

recipe init-counter [
  default-space:address:space <- new location:type, 30:literal
  x:integer <- copy 23:literal
  y:integer <- copy 3:literal  # variable that will be incremented
  reply default-space:address:space
]

recipe increment-counter [
  default-space:address:space <- new space:literal, 30:literal
  0:address:space/names:init-counter <- next-ingredient  # outer space must be created by 'init-counter' above
  y:integer/space:1 <- add y:integer/space:1, 1:literal  # increment
  y:integer <- copy 234:literal  # dummy
  reply y:integer/space:1
]

+name: recipe increment-counter is surrounded by init-counter
+mem: storing 5 in location 3

//: To make this work, compute the recipe that provides names for the
//: surrounding space of each recipe. This must happen before transform_names.

:(before "End Globals")
unordered_map<recipe_number, recipe_number> Surrounding_space;

:(after "int main")
  Transform.push_back(collect_surrounding_spaces);

:(code)
void collect_surrounding_spaces(const recipe_number r) {
  for (size_t i = 0; i < Recipe[r].steps.size(); ++i) {
    const instruction& inst = Recipe[r].steps[i];
    if (inst.is_label) continue;
    for (size_t j = 0; j < inst.products.size(); ++j) {
      if (isa_literal(inst.products[j])) continue;
      if (inst.products[j].name != "0") continue;
      if (inst.products[j].types.size() != 2
          || inst.products[j].types[0] != Type_number["address"]
          || inst.products[j].types[1] != Type_number["space"]) {
        raise << "slot 0 should always have type address:space, but is " << inst.products[j].to_string() << '\n';
        continue;
      }
      vector<string> s = property(inst.products[j], "names");
      if (s.empty())
        raise << "slot 0 requires a /names property in recipe " << Recipe[r].name << die();
      if (s.size() > 1) raise << "slot 0 should have a single value in /names, got " << inst.products[j].to_string() << '\n';
      string surrounding_recipe_name = s[0];
      if (Surrounding_space.find(r) != Surrounding_space.end()
          && Surrounding_space[r] != Recipe_number[surrounding_recipe_name]) {
        raise << "recipe " << Recipe[r].name << " can have only one 'surrounding' recipe but has " << Recipe[Surrounding_space[r]].name << " and " << surrounding_recipe_name << '\n';
        continue;
      }
      trace("name") << "recipe " << Recipe[r].name << " is surrounded by " << surrounding_recipe_name;
      Surrounding_space[r] = Recipe_number[surrounding_recipe_name];
    }
  }
}

vector<string> property(const reagent& r, const string& name) {
  for (size_t p = 0; p != r.properties.size(); ++p) {
    if (r.properties[p].first == name)
      return r.properties[p].second;
  }
  return vector<string>();
}

//: Once surrounding spaces are available, transform_names uses them to handle
//: /space properties.

:(replace{} "size_t lookup_name(const reagent& r, const recipe_number default_recipe)")
size_t lookup_name(const reagent& x, const recipe_number default_recipe) {
//?   cout << "AAA " << default_recipe << " " << Recipe[default_recipe].name << '\n'; //? 2
//?   cout << "AAA " << x.to_string() << '\n'; //? 1
  if (!has_property(x, "space")) {
    if (Name[default_recipe].empty()) raise << "name not found: " << x.name << '\n' << die();
    return Name[default_recipe][x.name];
  }
  vector<string> p = property(x, "space");
  if (p.size() != 1) raise << "/space property should have exactly one (non-negative integer) value\n";
  int n = to_int(p[0]);
  assert(n >= 0);
  recipe_number surrounding_recipe = lookup_surrounding_recipe(default_recipe, n);
  set<recipe_number> done;
  vector<recipe_number> path;
  return lookup_name(x, surrounding_recipe, done, path);
}

// If the recipe we need to lookup this name in doesn't have names done yet,
// recursively call transform_names on it.
size_t lookup_name(const reagent& x, const recipe_number r, set<recipe_number>& done, vector<recipe_number>& path) {
  if (!Name[r].empty()) return Name[r][x.name];
  if (done.find(r) != done.end()) {
    raise << "can't compute address of " << x.to_string() << " because ";
    for (size_t i = 1; i < path.size(); ++i) {
      raise << path[i-1] << " requires computing names of " << path[i] << '\n';
    }
    raise << path[path.size()-1] << " requires computing names of " << r << "..ad infinitum\n" << die();
    return 0;
  }
  done.insert(r);
  path.push_back(r);
  transform_names(r);  // Not passing 'done' through. Might this somehow cause an infinite loop?
  assert(!Name[r].empty());
  return Name[r][x.name];
}

recipe_number lookup_surrounding_recipe(const recipe_number r, size_t n) {
  if (n == 0) return r;
  if (Surrounding_space.find(r) == Surrounding_space.end()) {
    raise << "don't know surrounding recipe of " << Recipe[r].name << '\n';
    return 0;
  }
  assert(Surrounding_space[r]);
  return lookup_surrounding_recipe(Surrounding_space[r], n-1);
}

//: weaken use-before-set warnings just a tad
:(replace{} "bool already_transformed(const reagent& r, const unordered_map<string, int>& names)")
bool already_transformed(const reagent& r, const unordered_map<string, int>& names) {
  if (has_property(r, "space")) {
    vector<string> p = property(r, "space");
    assert(p.size() == 1);
    if (p[0] != "0") return true;
  }
  return names.find(r.name) != names.end();
}

:(before "End Includes")
#include<set>
using std::set;