2778 - fix all layers

1 files changed, 974 insertions, 0 deletions

diff --git a/058shape_shifting_recipe.cc b/058shape_shifting_recipe.cc
new file mode 100644
index 00000000..35791147
--- /dev/null
+++ b/058shape_shifting_recipe.cc
@@ -0,0 +1,974 @@
+//:: Like container definitions, recipes too can contain type parameters.
+
+:(scenario shape_shifting_recipe)
+def main [
+  10:point <- merge 14, 15
+  11:point <- foo 10:point
+]
+# non-matching variant
+def foo a:number -> result:number [
+  local-scope
+  load-ingredients
+  result <- copy 34
+]
+# matching shape-shifting variant
+def foo a:_t -> result:_t [
+  local-scope
+  load-ingredients
+  result <- copy a
+]
++mem: storing 14 in location 11
++mem: storing 15 in location 12
+
+//: Before anything else, disable transforms for shape-shifting recipes and
+//: make sure we never try to actually run a shape-shifting recipe. We should
+//: be rewriting such instructions to *specializations* with the type
+//: ingredients filled in.
+
+:(before "End Transform Checks")
+if (any_type_ingredient_in_header(/*recipe_ordinal*/p->first)) continue;
+
+:(after "Running One Instruction")
+if (Current_routine->calls.front().running_step_index == 0
+    && any_type_ingredient_in_header(Current_routine->calls.front().running_recipe)) {
+//?   DUMP("");
+  raise << "ran into unspecialized shape-shifting recipe " << current_recipe_name() << '\n' << end();
+//?   exit(0);
+}
+
+//: Make sure we don't match up literals with type ingredients without
+//: specialization.
+:(before "End Matching Types For Literal(to)")
+if (contains_type_ingredient_name(to)) return false;
+
+//: We'll be creating recipes without loading them from anywhere by
+//: *specializing* existing recipes.
+//:
+//: Keep track of these new recipes in a separate variable in addition to
+//: Recently_added_recipes, so that edit/ can clear them before reloading to
+//: regenerate errors.
+:(before "End Globals")
+vector<recipe_ordinal> Recently_added_shape_shifting_recipes;
+:(before "End Setup")
+Recently_added_shape_shifting_recipes.clear();
+
+//: make sure we don't clear any of these recipes when we start running tests
+:(before "End Loading .mu Files")
+Recently_added_recipes.clear();
+Recently_added_types.clear();
+Recently_added_shape_shifting_recipes.clear();
+
+//: save original name of specialized recipes
+:(before "End recipe Fields")
+string original_name;
+//: original name is only set during load
+:(before "End Load Recipe Name")
+result.original_name = result.name;
+
+:(after "Static Dispatch Phase 2")
+candidates = strictly_matching_shape_shifting_variants(inst, variants);
+if (!candidates.empty()) {
+  recipe_ordinal exemplar = best_shape_shifting_variant(inst, candidates);
+  trace(9992, "transform") << "found variant to specialize: " << exemplar << ' ' << get(Recipe, exemplar).name << end();
+  recipe_ordinal new_recipe_ordinal = new_variant(exemplar, inst, caller_recipe);
+  if (new_recipe_ordinal == 0) goto skip_shape_shifting_variants;
+  variants.push_back(new_recipe_ordinal);  // side-effect
+  recipe& variant = get(Recipe, new_recipe_ordinal);
+  // perform all transforms on the new specialization
+  if (!variant.steps.empty()) {
+    trace(9992, "transform") << "transforming new specialization: " << variant.name << end();
+    for (int t = 0; t < SIZE(Transform); ++t) {
+      (*Transform.at(t))(new_recipe_ordinal);
+    }
+  }
+  variant.transformed_until = SIZE(Transform)-1;
+  trace(9992, "transform") << "new specialization: " << variant.name << end();
+  return variant.name;
+}
+skip_shape_shifting_variants:;
+
+//: make sure we have no unspecialized shape-shifting recipes being called
+//: before running mu programs
+
+:(before "End Instruction Operation Checks")
+if (contains_key(Recipe, inst.operation) && inst.operation >= MAX_PRIMITIVE_RECIPES
+    && any_type_ingredient_in_header(inst.operation)) {
+  raise << maybe(caller.name) << "instruction " << inst.name << " has no valid specialization\n" << end();
+  return;
+}
+
+:(code)
+// phase 2 of static dispatch
+vector<recipe_ordinal> strictly_matching_shape_shifting_variants(const instruction& inst, vector<recipe_ordinal>& variants) {
+  vector<recipe_ordinal> result;
+  for (int i = 0; i < SIZE(variants); ++i) {
+    if (variants.at(i) == -1) continue;
+    if (!any_type_ingredient_in_header(variants.at(i))) continue;
+    if (all_concrete_header_reagents_strictly_match(inst, get(Recipe, variants.at(i))))
+      result.push_back(variants.at(i));
+  }
+  return result;
+}
+
+bool all_concrete_header_reagents_strictly_match(const instruction& inst, const recipe& variant) {
+  if (SIZE(inst.ingredients) < SIZE(variant.ingredients)) {
+    trace(9993, "transform") << "too few ingredients" << end();
+    return false;
+  }
+  if (SIZE(variant.products) < SIZE(inst.products)) {
+    trace(9993, "transform") << "too few products" << end();
+    return false;
+  }
+  for (int i = 0; i < SIZE(variant.ingredients); ++i) {
+    if (!concrete_type_names_strictly_match(variant.ingredients.at(i), inst.ingredients.at(i))) {
+      trace(9993, "transform") << "concrete-type match failed: ingredient " << i << end();
+      return false;
+    }
+  }
+  for (int i = 0; i < SIZE(inst.products); ++i) {
+    if (is_dummy(inst.products.at(i))) continue;
+    if (!concrete_type_names_strictly_match(variant.products.at(i), inst.products.at(i))) {
+      trace(9993, "transform") << "strict match failed: product " << i << end();
+      return false;
+    }
+  }
+  return true;
+}
+
+// tie-breaker for phase 2
+recipe_ordinal best_shape_shifting_variant(const instruction& inst, vector<recipe_ordinal>& candidates) {
+  assert(!candidates.empty());
+  // primary score
+  int max_score = -1;
+  for (int i = 0; i < SIZE(candidates); ++i) {
+    int score = number_of_concrete_type_names(candidates.at(i));
+    assert(score > -1);
+    if (score > max_score) max_score = score;
+  }
+  // break any ties at max_score by a secondary score
+  int min_score2 = 999;
+  int best_index = 0;
+  for (int i = 0; i < SIZE(candidates); ++i) {
+    int score1 = number_of_concrete_type_names(candidates.at(i));
+    assert(score1 <= max_score);
+    if (score1 != max_score) continue;
+    const recipe& candidate = get(Recipe, candidates.at(i));
+    int score2 = (SIZE(candidate.products)-SIZE(inst.products))
+                           + (SIZE(inst.ingredients)-SIZE(candidate.ingredients));
+    assert(score2 < 999);
+    if (score2 < min_score2) {
+      min_score2 = score2;
+      best_index = i;
+    }
+  }
+  return candidates.at(best_index);
+}
+
+bool any_type_ingredient_in_header(recipe_ordinal variant) {
+  const recipe& caller = get(Recipe, variant);
+  for (int i = 0; i < SIZE(caller.ingredients); ++i) {
+    if (contains_type_ingredient_name(caller.ingredients.at(i)))
+      return true;
+  }
+  for (int i = 0; i < SIZE(caller.products); ++i) {
+    if (contains_type_ingredient_name(caller.products.at(i)))
+      return true;
+  }
+  return false;
+}
+
+bool concrete_type_names_strictly_match(reagent to, reagent from) {
+  canonize_type(to);
+  canonize_type(from);
+  return concrete_type_names_strictly_match(to.type, from.type, from);
+}
+
+int number_of_concrete_type_names(recipe_ordinal r) {
+  const recipe& caller = get(Recipe, r);
+  int result = 0;
+  for (int i = 0; i < SIZE(caller.ingredients); ++i)
+    result += number_of_concrete_type_names(caller.ingredients.at(i));
+  for (int i = 0; i < SIZE(caller.products); ++i)
+    result += number_of_concrete_type_names(caller.products.at(i));
+  return result;
+}
+
+int number_of_concrete_type_names(const reagent& r) {
+  return number_of_concrete_type_names(r.type);
+}
+
+int number_of_concrete_type_names(const type_tree* type) {
+  if (!type) return 0;
+  int result = 0;
+  if (!type->name.empty() && !is_type_ingredient_name(type->name))
+    result++;
+  result += number_of_concrete_type_names(type->left);
+  result += number_of_concrete_type_names(type->right);
+  return result;
+}
+
+bool concrete_type_names_strictly_match(const type_tree* to, const type_tree* from, const reagent& rhs_reagent) {
+  if (!to) return !from;
+  if (!from) return !to;
+  if (is_type_ingredient_name(to->name)) return true;  // type ingredient matches anything
+  if (to->name == "literal" && from->name == "literal")
+    return true;
+  if (to->name == "literal"
+      && Literal_type_names.find(from->name) != Literal_type_names.end())
+    return true;
+  if (from->name == "literal"
+      && Literal_type_names.find(to->name) != Literal_type_names.end())
+    return true;
+  if (from->name == "literal" && to->name == "address")
+    return rhs_reagent.name == "0";
+  return to->name == from->name
+      && concrete_type_names_strictly_match(to->left, from->left, rhs_reagent)
+      && concrete_type_names_strictly_match(to->right, from->right, rhs_reagent);
+}
+
+bool contains_type_ingredient_name(const reagent& x) {
+  return contains_type_ingredient_name(x.type);
+}
+
+bool contains_type_ingredient_name(const type_tree* type) {
+  if (!type) return false;
+  if (is_type_ingredient_name(type->name)) return true;
+  return contains_type_ingredient_name(type->left) || contains_type_ingredient_name(type->right);
+}
+
+recipe_ordinal new_variant(recipe_ordinal exemplar, const instruction& inst, const recipe& caller_recipe) {
+  string new_name = next_unused_recipe_name(inst.name);
+  assert(!contains_key(Recipe_ordinal, new_name));
+  recipe_ordinal new_recipe_ordinal = put(Recipe_ordinal, new_name, Next_recipe_ordinal++);
+  // make a copy
+  assert(contains_key(Recipe, exemplar));
+  assert(!contains_key(Recipe, new_recipe_ordinal));
+  Recently_added_recipes.push_back(new_recipe_ordinal);
+  Recently_added_shape_shifting_recipes.push_back(new_recipe_ordinal);
+  put(Recipe, new_recipe_ordinal, get(Recipe, exemplar));
+  recipe& new_recipe = get(Recipe, new_recipe_ordinal);
+  new_recipe.name = new_name;
+  trace(9993, "transform") << "switching " << inst.name << " to specialized " << header_label(new_recipe_ordinal) << end();
+  // Since the exemplar never ran any transforms, we have to redo some of the
+  // work of the check_types_by_name transform while supporting type-ingredients.
+  compute_type_names(new_recipe);
+  // that gives enough information to replace type-ingredients with concrete types
+  {
+    map<string, const type_tree*> mappings;
+    bool error = false;
+    compute_type_ingredient_mappings(get(Recipe, exemplar), inst, mappings, caller_recipe, &error);
+    if (!error) replace_type_ingredients(new_recipe, mappings);
+    for (map<string, const type_tree*>::iterator p = mappings.begin(); p != mappings.end(); ++p)
+      delete p->second;
+    if (error) return 0;  // todo: delete new_recipe_ordinal from Recipes and other global state
+  }
+  ensure_all_concrete_types(new_recipe, get(Recipe, exemplar));
+  return new_recipe_ordinal;
+}
+
+void compute_type_names(recipe& variant) {
+  trace(9993, "transform") << "compute type names: " << variant.name << end();
+  map<string, type_tree*> type_names;
+  for (int i = 0; i < SIZE(variant.ingredients); ++i)
+    save_or_deduce_type_name(variant.ingredients.at(i), type_names, variant);
+  for (int i = 0; i < SIZE(variant.products); ++i)
+    save_or_deduce_type_name(variant.products.at(i), type_names, variant);
+  for (int i = 0; i < SIZE(variant.steps); ++i) {
+    instruction& inst = variant.steps.at(i);
+    trace(9993, "transform") << "  instruction: " << to_string(inst) << end();
+    for (int in = 0; in < SIZE(inst.ingredients); ++in)
+      save_or_deduce_type_name(inst.ingredients.at(in), type_names, variant);
+    for (int out = 0; out < SIZE(inst.products); ++out)
+      save_or_deduce_type_name(inst.products.at(out), type_names, variant);
+  }
+}
+
+void save_or_deduce_type_name(reagent& x, map<string, type_tree*>& type, const recipe& variant) {
+  trace(9994, "transform") << "    checking " << to_string(x) << ": " << names_to_string(x.type) << end();
+  if (!x.type && contains_key(type, x.name)) {
+    x.type = new type_tree(*get(type, x.name)); //TODO
+    trace(9994, "transform") << "    deducing type to " << names_to_string(x.type) << end();
+    return;
+  }
+  if (!x.type) {
+    raise << maybe(variant.original_name) << "unknown type for " << x.original_string << " (check the name for typos)\n" << end();
+    return;
+  }
+  if (contains_key(type, x.name)) return;
+  if (x.type->name == "offset" || x.type->name == "variant") return;  // special-case for container-access instructions
+  put(type, x.name, x.type);
+  trace(9993, "transform") << "type of " << x.name << " is " << names_to_string(x.type) << end();
+}
+
+void compute_type_ingredient_mappings(const recipe& exemplar, const instruction& inst, map<string, const type_tree*>& mappings, const recipe& caller_recipe, bool* error) {
+  int limit = min(SIZE(inst.ingredients), SIZE(exemplar.ingredients));
+  for (int i = 0; i < limit; ++i) {
+    const reagent& exemplar_reagent = exemplar.ingredients.at(i);
+    reagent ingredient = inst.ingredients.at(i);
+    canonize_type(ingredient);
+    if (is_mu_address(exemplar_reagent) && ingredient.name == "0") continue;  // assume it matches
+    accumulate_type_ingredients(exemplar_reagent, ingredient, mappings, exemplar, inst, caller_recipe, error);
+  }
+  limit = min(SIZE(inst.products), SIZE(exemplar.products));
+  for (int i = 0; i < limit; ++i) {
+    const reagent& exemplar_reagent = exemplar.products.at(i);
+    reagent product = inst.products.at(i);
+    canonize_type(product);
+    accumulate_type_ingredients(exemplar_reagent, product, mappings, exemplar, inst, caller_recipe, error);
+  }
+}
+
+inline int min(int a, int b) {
+  return (a < b) ? a : b;
+}
+
+void accumulate_type_ingredients(const reagent& exemplar_reagent, reagent& refinement, map<string, const type_tree*>& mappings, const recipe& exemplar, const instruction& call_instruction, const recipe& caller_recipe, bool* error) {
+  assert(refinement.type);
+  accumulate_type_ingredients(exemplar_reagent.type, refinement.type, mappings, exemplar, exemplar_reagent, call_instruction, caller_recipe, error);
+}
+
+void accumulate_type_ingredients(const type_tree* exemplar_type, const type_tree* refinement_type, map<string, const type_tree*>& mappings, const recipe& exemplar, const reagent& exemplar_reagent, const instruction& call_instruction, const recipe& caller_recipe, bool* error) {
+  if (!exemplar_type) return;
+  if (!refinement_type) {
+    // todo: make this smarter; only flag an error if exemplar_type contains some *new* type ingredient
+    raise << maybe(exemplar.name) << "missing type ingredient in " << exemplar_reagent.original_string << '\n' << end();
+    return;
+  }
+  if (is_type_ingredient_name(exemplar_type->name)) {
+    const type_tree* curr_refinement_type = NULL;  // temporary heap allocation; must always be deleted before it goes out of scope
+    if (refinement_type->left)
+      curr_refinement_type = new type_tree(*refinement_type->left);
+    else if (exemplar_type->right)
+      // splice out refinement_type->right, it'll be used later by the exemplar_type->right
+      curr_refinement_type = new type_tree(refinement_type->name, refinement_type->value, NULL);
+    else
+      curr_refinement_type = new type_tree(*refinement_type);
+    assert(!curr_refinement_type->left);
+    if (!contains_key(mappings, exemplar_type->name)) {
+      trace(9993, "transform") << "adding mapping from " << exemplar_type->name << " to " << to_string(curr_refinement_type) << end();
+      put(mappings, exemplar_type->name, new type_tree(*curr_refinement_type));
+    }
+    else {
+      if (!deeply_equal_type_names(get(mappings, exemplar_type->name), curr_refinement_type)) {
+        raise << maybe(caller_recipe.name) << "no call found for '" << to_string(call_instruction) << "'\n" << end();
+        *error = true;
+        delete curr_refinement_type;
+        return;
+      }
+      if (get(mappings, exemplar_type->name)->name == "literal") {
+        delete get(mappings, exemplar_type->name);
+        put(mappings, exemplar_type->name, new type_tree(*curr_refinement_type));
+      }
+    }
+    delete curr_refinement_type;
+  }
+  else {
+    accumulate_type_ingredients(exemplar_type->left, refinement_type->left, mappings, exemplar, exemplar_reagent, call_instruction, caller_recipe, error);
+  }
+  accumulate_type_ingredients(exemplar_type->right, refinement_type->right, mappings, exemplar, exemplar_reagent, call_instruction, caller_recipe, error);
+}
+
+void replace_type_ingredients(recipe& new_recipe, const map<string, const type_tree*>& mappings) {
+  // update its header
+  if (mappings.empty()) return;
+  trace(9993, "transform") << "replacing in recipe header ingredients" << end();
+  for (int i = 0; i < SIZE(new_recipe.ingredients); ++i)
+    replace_type_ingredients(new_recipe.ingredients.at(i), mappings, new_recipe);
+  trace(9993, "transform") << "replacing in recipe header products" << end();
+  for (int i = 0; i < SIZE(new_recipe.products); ++i)
+    replace_type_ingredients(new_recipe.products.at(i), mappings, new_recipe);
+  // update its body
+  for (int i = 0; i < SIZE(new_recipe.steps); ++i) {
+    instruction& inst = new_recipe.steps.at(i);
+    trace(9993, "transform") << "replacing in instruction '" << to_string(inst) << "'" << end();
+    for (int j = 0; j < SIZE(inst.ingredients); ++j)
+      replace_type_ingredients(inst.ingredients.at(j), mappings, new_recipe);
+    for (int j = 0; j < SIZE(inst.products); ++j)
+      replace_type_ingredients(inst.products.at(j), mappings, new_recipe);
+    // special-case for new: replace type ingredient in first ingredient *value*
+    if (inst.name == "new" && inst.ingredients.at(0).type->name != "literal-string") {
+      type_tree* type = parse_type_tree(inst.ingredients.at(0).name);
+      replace_type_ingredients(type, mappings);
+      inst.ingredients.at(0).name = inspect(type);
+      delete type;
+    }
+  }
+}
+
+void replace_type_ingredients(reagent& x, const map<string, const type_tree*>& mappings, const recipe& caller) {
+  string before = to_string(x);
+  trace(9993, "transform") << "replacing in ingredient " << x.original_string << end();
+  if (!x.type) {
+    raise << "specializing " << caller.original_name << ": missing type for " << x.original_string << '\n' << end();
+    return;
+  }
+  replace_type_ingredients(x.type, mappings);
+}
+
+// todo: too complicated and likely incomplete; maybe avoid replacing in place?
+void replace_type_ingredients(type_tree* type, const map<string, const type_tree*>& mappings) {
+  if (!type) return;
+  if (contains_key(Type_ordinal, type->name))  // todo: ugly side effect
+    type->value = get(Type_ordinal, type->name);
+  if (!is_type_ingredient_name(type->name) || !contains_key(mappings, type->name)) {
+    replace_type_ingredients(type->left, mappings);
+    replace_type_ingredients(type->right, mappings);
+    return;
+  }
+
+  const type_tree* replacement = get(mappings, type->name);
+  trace(9993, "transform") << type->name << " => " << names_to_string(replacement) << end();
+
+  // type is a single type ingredient
+  assert(!type->left);
+  if (!type->right) assert(!replacement->left);
+
+  if (!replacement->right) {
+    if (!replacement->left) {
+      type->name = (replacement->name == "literal") ? "number" : replacement->name;
+      type->value = get(Type_ordinal, type->name);
+    }
+    else {
+      type->name = "";
+      type->value = 0;
+      type->left = new type_tree(*replacement);
+    }
+    replace_type_ingredients(type->right, mappings);
+  }
+  // replace non-last type?
+  else if (type->right) {
+    type->name = "";
+    type->value = 0;
+    type->left = new type_tree(*replacement);
+    replace_type_ingredients(type->right, mappings);
+  }
+  // replace last type?
+  else {
+    type->name = replacement->name;
+    type->value = get(Type_ordinal, type->name);
+    type->right = new type_tree(*replacement->right);
+  }
+}
+
+type_tree* parse_type_tree(const string& s) {
+  istringstream in(s);
+  in >> std::noskipws;
+  return parse_type_tree(in);
+}
+
+type_tree* parse_type_tree(istream& in) {
+  skip_whitespace_but_not_newline(in);
+  if (!has_data(in)) return NULL;
+  if (in.peek() == ')') {
+    in.get();
+    return NULL;
+  }
+  if (in.peek() != '(') {
+    string type_name = next_word(in);
+    if (!contains_key(Type_ordinal, type_name))
+      put(Type_ordinal, type_name, Next_type_ordinal++);
+    type_tree* result = new type_tree(type_name, get(Type_ordinal, type_name));
+    return result;
+  }
+  in.get();  // skip '('
+  type_tree* result = NULL;
+  type_tree** curr = &result;
+  while (in.peek() != ')') {
+    assert(has_data(in));
+    *curr = new type_tree("", 0);
+    skip_whitespace_but_not_newline(in);
+    if (in.peek() == '(')
+      (*curr)->left = parse_type_tree(in);
+    else {
+      (*curr)->name = next_word(in);
+      if (!is_type_ingredient_name((*curr)->name)) {
+        if (!contains_key(Type_ordinal, (*curr)->name))
+          put(Type_ordinal, (*curr)->name, Next_type_ordinal++);
+        (*curr)->value = get(Type_ordinal, (*curr)->name);
+      }
+    }
+    curr = &(*curr)->right;
+  }
+  in.get();  // skip ')'
+  return result;
+}
+
+string inspect(const type_tree* x) {
+  ostringstream out;
+  dump_inspect(x, out);
+  return out.str();
+}
+
+void dump_inspect(const type_tree* x, ostream& out) {
+  if (!x->left && !x->right) {
+    out << x->name;
+    return;
+  }
+  out << '(';
+  for (const type_tree* curr = x; curr; curr = curr->right) {
+    if (curr != x) out << ' ';
+    if (curr->left)
+      dump_inspect(curr->left, out);
+    else
+      out << curr->name;
+  }
+  out << ')';
+}
+
+void ensure_all_concrete_types(/*const*/ recipe& new_recipe, const recipe& exemplar) {
+  for (int i = 0; i < SIZE(new_recipe.ingredients); ++i)
+    ensure_all_concrete_types(new_recipe.ingredients.at(i), exemplar);
+  for (int i = 0; i < SIZE(new_recipe.products); ++i)
+    ensure_all_concrete_types(new_recipe.products.at(i), exemplar);
+  for (int i = 0; i < SIZE(new_recipe.steps); ++i) {
+    instruction& inst = new_recipe.steps.at(i);
+    for (int j = 0; j < SIZE(inst.ingredients); ++j)
+      ensure_all_concrete_types(inst.ingredients.at(j), exemplar);
+    for (int j = 0; j < SIZE(inst.products); ++j)
+      ensure_all_concrete_types(inst.products.at(j), exemplar);
+  }
+}
+
+void ensure_all_concrete_types(/*const*/ reagent& x, const recipe& exemplar) {
+  if (!x.type || contains_type_ingredient_name(x.type)) {
+    raise << maybe(exemplar.name) << "failed to map a type to " << x.original_string << '\n' << end();
+    if (!x.type) x.type = new type_tree("", 0);  // just to prevent crashes later
+    return;
+  }
+  if (x.type->value == -1) {
+    raise << maybe(exemplar.name) << "failed to map a type to the unknown " << x.original_string << '\n' << end();
+    return;
+  }
+}
+
+:(scenario shape_shifting_recipe_2)
+def main [
+  10:point <- merge 14, 15
+  11:point <- foo 10:point
+]
+# non-matching shape-shifting variant
+def foo a:_t, b:_t -> result:number [
+  local-scope
+  load-ingredients
+  result <- copy 34
+]
+# matching shape-shifting variant
+def foo a:_t -> result:_t [
+  local-scope
+  load-ingredients
+  result <- copy a
+]
++mem: storing 14 in location 11
++mem: storing 15 in location 12
+
+:(scenario shape_shifting_recipe_nonroot)
+def main [
+  10:foo:point <- merge 14, 15, 16
+  20:point/raw <- bar 10:foo:point
+]
+# shape-shifting recipe with type ingredient following some other type
+def bar a:foo:_t -> result:_t [
+  local-scope
+  load-ingredients
+  result <- get a, x:offset
+]
+container foo:_t [
+  x:_t
+  y:number
+]
++mem: storing 14 in location 20
++mem: storing 15 in location 21
+
+:(scenario shape_shifting_recipe_nested)
+container c:_a:_b [
+  a:_a
+  b:_b
+]
+def main [
+  s:address:shared:array:character <- new [abc]
+  {x: (c (address shared array character) number)} <- merge s, 34
+  foo x
+]
+def foo x:c:_bar:_baz [
+  local-scope
+  load-ingredients
+]
+
+:(scenario shape_shifting_recipe_type_deduction_ignores_offsets)
+def main [
+  10:foo:point <- merge 14, 15, 16
+  20:point/raw <- bar 10:foo:point
+]
+def bar a:foo:_t -> result:_t [
+  local-scope
+  load-ingredients
+  x:number <- copy 1
+  result <- get a, x:offset  # shouldn't collide with other variable
+]
+container foo:_t [
+  x:_t
+  y:number
+]
++mem: storing 14 in location 20
++mem: storing 15 in location 21
+
+:(scenario shape_shifting_recipe_empty)
+def main [
+  foo 1
+]
+# shape-shifting recipe with no body
+def foo a:_t [
+]
+# shouldn't crash
+
+:(scenario shape_shifting_recipe_handles_shape_shifting_new_ingredient)
+def main [
+  1:address:shared:foo:point <- bar 3
+  11:foo:point <- copy *1:address:shared:foo:point
+]
+container foo:_t [
+  x:_t
+  y:number
+]
+def bar x:number -> result:address:shared:foo:_t [
+  local-scope
+  load-ingredients
+  # new refers to _t in its ingredient *value*
+  result <- new {(foo _t) : type}
+]
++mem: storing 0 in location 11
++mem: storing 0 in location 12
++mem: storing 0 in location 13
+
+:(scenario shape_shifting_recipe_handles_shape_shifting_new_ingredient_2)
+def main [
+  1:address:shared:foo:point <- bar 3
+  11:foo:point <- copy *1:address:shared:foo:point
+]
+def bar x:number -> result:address:shared:foo:_t [
+  local-scope
+  load-ingredients
+  # new refers to _t in its ingredient *value*
+  result <- new {(foo _t) : type}
+]
+# container defined after use
+container foo:_t [
+  x:_t
+  y:number
+]
++mem: storing 0 in location 11
++mem: storing 0 in location 12
++mem: storing 0 in location 13
+
+:(scenario shape_shifting_recipe_supports_compound_types)
+def main [
+  1:address:shared:point <- new point:type
+  2:address:number <- get-address *1:address:shared:point, y:offset
+  *2:address:number <- copy 34
+  3:address:shared:point <- bar 1:address:shared:point  # specialize _t to address:shared:point
+  4:point <- copy *3:address:shared:point
+]
+def bar a:_t -> result:_t [
+  local-scope
+  load-ingredients
+  result <- copy a
+]
++mem: storing 34 in location 5
+
+:(scenario shape_shifting_recipe_error)
+% Hide_errors = true;
+def main [
+  a:number <- copy 3
+  b:address:shared:number <- foo a
+]
+def foo a:_t -> b:_t [
+  load-ingredients
+  b <- copy a
+]
++error: main: no call found for 'b:address:shared:number <- foo a'
+
+:(scenario specialize_inside_recipe_without_header)
+def main [
+  foo 3
+]
+def foo [
+  local-scope
+  x:number <- next-ingredient  # ensure no header
+  1:number/raw <- bar x  # call a shape-shifting recipe
+]
+def bar x:_elem -> y:_elem [
+  local-scope
+  load-ingredients
+  y <- add x, 1
+]
++mem: storing 4 in location 1
+
+:(scenario specialize_with_literal)
+def main [
+  local-scope
+  # permit literal to map to number
+  1:number/raw <- foo 3
+]
+def foo x:_elem -> y:_elem [
+  local-scope
+  load-ingredients
+  y <- add x, 1
+]
++mem: storing 4 in location 1
+
+:(scenario specialize_with_literal_2)
+def main [
+  local-scope
+  # permit literal to map to character
+  1:character/raw <- foo 3
+]
+def foo x:_elem -> y:_elem [
+  local-scope
+  load-ingredients
+  y <- add x, 1
+]
++mem: storing 4 in location 1
+
+:(scenario specialize_with_literal_3)
+def main [
+  local-scope
+  # permit '0' to map to address to shape-shifting type-ingredient
+  1:address:shared:character/raw <- foo 0
+]
+def foo x:address:_elem -> y:address:_elem [
+  local-scope
+  load-ingredients
+  y <- copy x
+]
++mem: storing 0 in location 1
+$error: 0
+
+:(scenario specialize_with_literal_4)
+% Hide_errors = true;
+def main [
+  local-scope
+  # ambiguous call: what's the type of its ingredient?!
+  foo 0
+]
+def foo x:address:_elem -> y:address:_elem [
+  local-scope
+  load-ingredients
+  y <- copy x
+]
++error: foo: failed to map a type to x
++error: foo: failed to map a type to y
+
+:(scenario specialize_with_literal_5)
+def main [
+  foo 3, 4  # recipe mapping two variables to literals
+]
+def foo x:_elem, y:_elem [
+  local-scope
+  load-ingredients
+  1:number/raw <- add x, y
+]
++mem: storing 7 in location 1
+
+:(scenario multiple_shape_shifting_variants)
+# try to call two different shape-shifting recipes with the same name
+def main [
+  e1:d1:number <- merge 3
+  e2:d2:number <- merge 4, 5
+  1:number/raw <- foo e1
+  2:number/raw <- foo e2
+]
+# the two shape-shifting definitions
+def foo a:d1:_elem -> b:number [
+  local-scope
+  load-ingredients
+  return 34
+]
+def foo a:d2:_elem -> b:number [
+  local-scope
+  load-ingredients
+  return 35
+]
+# the shape-shifting containers they use
+container d1:_elem [
+  x:_elem
+]
+container d2:_elem [
+  x:number
+  y:_elem
+]
++mem: storing 34 in location 1
++mem: storing 35 in location 2
+
+:(scenario multiple_shape_shifting_variants_2)
+# static dispatch between shape-shifting variants, _including pointer lookups_
+def main [
+  e1:d1:number <- merge 3
+  e2:address:shared:d2:number <- new {(d2 number): type}
+  1:number/raw <- foo e1
+  2:number/raw <- foo *e2  # different from previous scenario
+]
+def foo a:d1:_elem -> b:number [
+  local-scope
+  load-ingredients
+  return 34
+]
+def foo a:d2:_elem -> b:number [
+  local-scope
+  load-ingredients
+  return 35
+]
+container d1:_elem [
+  x:_elem
+]
+container d2:_elem [
+  x:number
+  y:_elem
+]
++mem: storing 34 in location 1
++mem: storing 35 in location 2
+
+:(scenario missing_type_in_shape_shifting_recipe)
+% Hide_errors = true;
+def main [
+  a:d1:number <- merge 3
+  foo a
+]
+def foo a:d1:_elem -> b:number [
+  local-scope
+  load-ingredients
+  copy e  # no such variable
+  return 34
+]
+container d1:_elem [
+  x:_elem
+]
++error: foo: unknown type for e (check the name for typos)
++error: specializing foo: missing type for e
+# and it doesn't crash
+
+:(scenario missing_type_in_shape_shifting_recipe_2)
+% Hide_errors = true;
+def main [
+  a:d1:number <- merge 3
+  foo a
+]
+def foo a:d1:_elem -> b:number [
+  local-scope
+  load-ingredients
+  get e, x:offset  # unknown variable in a 'get', which does some extra checking
+  return 34
+]
+container d1:_elem [
+  x:_elem
+]
++error: foo: unknown type for e (check the name for typos)
++error: specializing foo: missing type for e
+# and it doesn't crash
+
+:(scenarios transform)
+:(scenario specialize_recursive_shape_shifting_recipe)
+def main [
+  1:number <- copy 34
+  2:number <- foo 1:number
+]
+def foo x:_elem -> y:number [
+  local-scope
+  load-ingredients
+  {
+    break
+    y:number <- foo x
+  }
+  return y
+]
++transform: new specialization: foo_2
+# transform terminates
+
+:(scenarios run)
+:(scenario specialize_most_similar_variant)
+def main [
+  1:address:shared:number <- new number:type
+  2:number <- foo 1:address:shared:number
+]
+def foo x:_elem -> y:number [
+  local-scope
+  load-ingredients
+  return 34
+]
+def foo x:address:shared:_elem -> y:number [
+  local-scope
+  load-ingredients
+  return 35
+]
++mem: storing 35 in location 2
+
+:(scenario specialize_most_similar_variant_2)
+# version with headers padded with lots of unrelated concrete types
+def main [
+  1:number <- copy 23
+  2:address:shared:array:number <- copy 0
+  3:number <- foo 2:address:shared:array:number, 1:number
+]
+# variant with concrete type
+def foo dummy:address:shared:array:number, x:number -> y:number, dummy:address:shared:array:number [
+  local-scope
+  load-ingredients
+  return 34
+]
+# shape-shifting variant
+def foo dummy:address:shared:array:number, x:_elem -> y:number, dummy:address:shared:array:number [
+  local-scope
+  load-ingredients
+  return 35
+]
+# prefer the concrete variant
++mem: storing 34 in location 3
+
+:(scenario specialize_most_similar_variant_3)
+def main [
+  1:address:shared:array:character <- new [abc]
+  foo 1:address:shared:array:character
+]
+def foo x:address:shared:array:character [
+  2:number <- copy 34
+]
+def foo x:address:_elem [
+  2:number <- copy 35
+]
+# make sure the more precise version was used
++mem: storing 34 in location 2
+
+:(scenario specialize_literal_as_number)
+def main [
+  1:number <- foo 23
+]
+def foo x:_elem -> y:number [
+  local-scope
+  load-ingredients
+  return 34
+]
+def foo x:character -> y:number [
+  local-scope
+  load-ingredients
+  return 35
+]
++mem: storing 34 in location 1
+
+:(scenario specialize_literal_as_number_2)
+# version calling with literal
+def main [
+  1:number <- foo 0
+]
+# variant with concrete type
+def foo x:number -> y:number [
+  local-scope
+  load-ingredients
+  return 34
+]
+# shape-shifting variant
+def foo x:address:shared:_elem -> y:number [
+  local-scope
+  load-ingredients
+  return 35
+]
+# prefer the concrete variant, ignore concrete types in scoring the shape-shifting variant
++mem: storing 34 in location 1