//: Construct types out of their constituent fields. :(scenario merge) container foo [ x:num y:num ] def main [ 1:foo <- merge 3, 4 ] +mem: storing 3 in location 1 +mem: storing 4 in location 2 :(before "End Primitive Recipe Declarations") MERGE, :(before "End Primitive Recipe Numbers") put(Recipe_ordinal, "merge", MERGE); :(before "End Primitive Recipe Checks") case MERGE: { // type-checking in a separate transform below break; } :(before "End Primitive Recipe Implementations") case MERGE: { products.resize(1); for (int i = 0; i < SIZE(ingredients); ++i) for (int j = 0; j < SIZE(ingredients.at(i)); ++j) products.at(0).push_back(ingredients.at(i).at(j)); break; } //: type-check 'merge' to avoid interpreting numbers as addresses :(scenario merge_check) def main [ 1:point <- merge 3, 4 ] $error: 0 :(scenario merge_check_missing_element) % Hide_errors = true; def main [ 1:point <- merge 3 ] +error: main: too few ingredients in '1:point <- merge 3' :(scenario merge_check_extra_element) % Hide_errors = true; def main [ 1:point <- merge 3, 4, 5 ] +error: main: too many ingredients in '1:point <- merge 3, 4, 5' //: We want to avoid causing memory corruption, but other than that we want to //: be flexible in how we construct containers of containers. It should be //: equally easy to define a container out of primitives or intermediate //: container fields. :(scenario merge_check_recursive_containers) def main [ 1:point <- merge 3, 4 1:point-number <- merge 1:point, 5 ] $error: 0 :(scenario merge_check_recursive_containers_2) % Hide_errors = true; def main [ 1:point <- merge 3, 4 2:point-number <- merge 1:point ] +error: main: too few ingredients in '2:point-number <- merge 1:point' :(scenario merge_check_recursive_containers_3) def main [ 1:point-number <- merge 3, 4, 5 ] $error: 0 :(scenario merge_check_recursive_containers_4) % Hide_errors = true; def main [ 1:point-number <- merge 3, 4 ] +error: main: too few ingredients in '1:point-number <- merge 3, 4' :(scenario merge_check_reflexive) % Hide_errors = true; def main [ 1:point <- merge 3, 4 2:point <- merge 1:point ] $error: 0 //: Since a container can be merged in several ways, we need to be able to //: backtrack through different possibilities. Later we'll allow creating //: exclusive containers which contain just one of rather than all of their //: elements. That will also require backtracking capabilities. Here's the //: state we need to maintain for backtracking: :(before "End Types") struct merge_check_point { reagent container; int container_element_index; merge_check_point(const reagent& c, int i) :container(c), container_element_index(i) {} }; struct merge_check_state { stack data; }; :(before "End Checks") Transform.push_back(check_merge_calls); // idempotent :(code) void check_merge_calls(const recipe_ordinal r) { const recipe& caller = get(Recipe, r); trace(9991, "transform") << "--- type-check merge instructions in recipe " << caller.name << end(); for (int i = 0; i < SIZE(caller.steps); ++i) { const instruction& inst = caller.steps.at(i); if (inst.name != "merge") continue; if (SIZE(inst.products) != 1) { raise << maybe(caller.name) << "'merge' should yield a single product in '" << to_original_string(inst) << "'\n" << end(); continue; } reagent/*copy*/ product = inst.products.at(0); // Update product While Type-checking Merge const type_tree* product_base_type = product.type->atom ? product.type : product.type->left; assert(product_base_type->atom); if (product_base_type->value == 0 || !contains_key(Type, product_base_type->value)) { raise << maybe(caller.name) << "'merge' should yield a container in '" << to_original_string(inst) << "'\n" << end(); continue; } const type_info& info = get(Type, product_base_type->value); if (info.kind != CONTAINER && info.kind != EXCLUSIVE_CONTAINER) { raise << maybe(caller.name) << "'merge' should yield a container in '" << to_original_string(inst) << "'\n" << end(); continue; } check_merge_call(inst.ingredients, product, caller, inst); } } void check_merge_call(const vector& ingredients, const reagent& product, const recipe& caller, const instruction& inst) { int ingredient_index = 0; merge_check_state state; state.data.push(merge_check_point(product, 0)); while (true) { assert(!state.data.empty()); trace("transform") << ingredient_index << " vs " << SIZE(ingredients) << end(); if (ingredient_index >= SIZE(ingredients)) { raise << maybe(caller.name) << "too few ingredients in '" << to_original_string(inst) << "'\n" << end(); return; } reagent& container = state.data.top().container; if (!container.type) return; // error handled elsewhere const type_tree* top_root_type = container.type->atom ? container.type : container.type->left; assert(top_root_type->atom); type_info& container_info = get(Type, top_root_type->value); switch (container_info.kind) { case CONTAINER: { // degenerate case: merge with the same type always succeeds if (state.data.top().container_element_index == 0 && types_coercible(container, inst.ingredients.at(ingredient_index))) return; const reagent& expected_ingredient = element_type(container.type, state.data.top().container_element_index); trace("transform") << "checking container " << to_string(container) << " || " << to_string(expected_ingredient) << " vs ingredient " << ingredient_index << end(); // if the current element is the ingredient we expect, move on to the next element/ingredient if (types_coercible(expected_ingredient, ingredients.at(ingredient_index))) { ++ingredient_index; ++state.data.top().container_element_index; while (state.data.top().container_element_index >= SIZE(get(Type, get_base_type(state.data.top().container.type)->value).elements)) { state.data.pop(); if (state.data.empty()) { if (ingredient_index < SIZE(ingredients)) raise << maybe(caller.name) << "too many ingredients in '" << to_original_string(inst) << "'\n" << end(); return; } ++state.data.top().container_element_index; } } // if not, maybe it's a field of t