//: 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<merge_check_point> 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<reagent>& 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(9999, "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(9999, "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 the current element
else {
// no change to ingredient_index
state.data.push(merge_check_point(expected_ingredient, 0));
}
break;
}
// End check_merge_call Special-cases
default: {
if (!types_coercible(container, ingredients.at(ingredient_index))) {
raise << maybe(caller.name) << "incorrect type of ingredient " << ingredient_index << " in '" << to_original_string(inst) << "'\n" << end();
raise << " (expected '" << debug_string(container) << "')\n" << end();
raise << " (got '" << debug_string(ingredients.at(ingredient_index)) << "')\n" << end();
return;
}
++ingredient_index;
// ++state.data.top().container_element_index; // unnecessary, but wouldn't do any harm
do {
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;
} while (state.data.top().container_element_index >= SIZE(get(Type, get_base_type(state.data.top().container.type)->value).elements));
}
}
}
// never gets here
assert(false);
}
//: replaced in a later layer
//: todo: find some clean way to take this call completely out of this layer
const type_tree* get_base_type(const type_tree* t) {
return t;
}
:(scenario merge_check_product)
% Hide_errors = true;
def main [
1:num <- merge 3
]
+error: main: 'merge' should yield a container in '1:num <- merge 3'
:(before "End Includes")
#include <stack>
using std::stack;