Mu - 031merge.cc

https://github.com/akkartik/mu/blob/master/031merge.cc

  1 //: Construct types out of their constituent fields.
  2 
  3 :(scenario merge)
  4 container foo [
  5   x:num
  6   y:num
  7 ]
  8 def main [
  9   1:foo <- merge 3, 4
 10 ]
 11 +mem: storing 3 in location 1
 12 +mem: storing 4 in location 2
../../ranger/config/commands.py

or intermediate 57 //: container fields. 58 59 :(scenario merge_check_recursive_containers) 60 def main [ 61 1:point <- merge 3, 4 62 1:point-number <- merge 1:point, 5 63 ] 64 $error: 0 65 66 :(scenario merge_check_recursive_containers_2) 67 % Hide_errors = true; 68 def main [ 69 1:point <- merge 3, 4 70 2:point-number <- merge 1:point 71 ] 72 +error: main: too few ingredients in '2:point-number <- merge 1:point' 73 74 :(scenario merge_check_recursive_containers_3) 75 def main [ 76 1:point-number <- merge 3, 4, 5 77 ] 78 $error: 0 79 80 :(scenario merge_check_recursive_containers_4) 81 % Hide_errors = true; 82 def main [ 83 1:point-number <- merge 3, 4 84 ] 85 +error: main: too few ingredients in '1:point-number <- merge 3, 4' 86 87 :(scenario merge_check_reflexive) 88 % Hide_errors = true; 89 def main [ 90 1:point <- merge 3, 4 91 2:point <- merge 1:point 92 ] 93 $error: 0 94 95 //: Since a container can be merged in several ways, we need to be able to 96 //: backtrack through different possibilities. Later we'll allow creating 97 //: exclusive containers which contain just one of rather than all of their 98 //: elements. That will also require backtracking capabilities. Here's the 99 //: state we need to maintain for backtracking: 100 101 :(before "End Types") 102 struct merge_check_point { 103 reagent container; 104 int container_element_index; 105 merge_check_point(const reagent& c, int i) :container(c), container_element_index(i) {} 106 }; 107 108 struct merge_check_state { 109 stack<merge_check_point> data; 110 }; 111 112 :(before "End Checks") 113 Transform.push_back(check_merge_calls); // idempotent 114 :(code) 115 void check_merge_calls(const recipe_ordinal r) { 116 const recipe& caller = get(Recipe, r); 117 trace(9991, "transform") << "--- type-check merge instructions in recipe " << caller.name << end(); 118 for (int i = 0; i < SIZE(caller.steps); ++i) { 119 const instruction& inst = caller.steps.at(i); 120 if (inst.name != "merge") continue; 121 if (SIZE(inst.products) != 1) { 122 raise << maybe(caller.name) << "'merge' should yield a single product in '" << to_original_string(inst) << "'\n" << end(); 123 continue; 124 } 125 reagent/*copy*/ product = inst.products.at(0); 126 // Update product While Type-checking Merge 127 const type_tree* product_base_type = product.type->atom ? product.type : product.type->left; 128 assert(product_base_type->atom); 129 if (product_base_type->value == 0 || !contains_key(Type, product_base_type->value)) { 130 raise << maybe(caller.name) << "'merge' should yield a container in '" << to_original_string(inst) << "'\n" << end(); 131 continue; 132 } 133 const type_info& info = get(Type, product_base_type->value); 134 if (info.kind != CONTAINER && info.kind != EXCLUSIVE_CONTAINER) { 135 raise << maybe(caller.name) << "'merge' should yield a container in '" << to_original_string(inst) << "'\n" << end(); 136 continue; 137 } 138 check_merge_call(inst.ingredients, product, caller, inst); 139 } 140 } 141 142 void check_merge_call(const vector<reagent>& ingredients, const reagent& product, const recipe& caller, const instruction& inst) { 143 int ingredient_index = 0; 144 merge_check_state state; 145 state.data.push(merge_check_point(product, 0)); 146 while (true) { 147 assert(!state.data.empty()); 148 trace("transform") << ingredient_index << " vs " << SIZE(ingredients) << end(); 149 if (ingredient_index >= SIZE(ingredients)) { 150 raise << maybe(caller.name) << "too few ingredients in '" << to_original_string(inst) << "'\n" << end(); 151 return; 152 } 153 reagent& container = state.data.top().container; 154 if (!container.type) return; // error handled elsewhere 155 const type_tree* top_root_type = container.type->atom ? container.type : container.type->left; 156 assert(top_root_type->atom); 157 type_info& container_info = get(Type, top_root_type->value); 158 switch (container_info.kind) { 159 case CONTAINER: { 160 // degenerate case: merge with the same type always succeeds 161 if (state.data.top().container_element_index == 0 && types_coercible(container, inst.ingredients.at(ingredient_index))) 162 return; 163 const reagent& expected_ingredient = element_type(container.type, state.data.top().container_element_index); 164 trace("transform") << "checking container " << to_string(container) << " || " << to_string(expected_ingredient) << " vs ingredient " << ingredient_index << end(); 165 // if the current element is the ingredient we expect, move on to the next element/ingredient 166 if (types_coercible(expected_ingredient, ingredients.at(ingredient_index))) { 167 ++ingredient_index; 168 ++state.data.top().container_element_index; 169 while (state.data.top().container_element_index >= SIZE(get(Type, get_base_type(state.data.top().container.type)->value).elements)) { 170 state.data.pop(); 171 if (state.data.empty()) { 172 if (ingredient_index < SIZE(ingredients)) 173 raise << maybe(caller.name) << "too many ingredients in '" << to_original_string(inst) << "'\n" << end(); 174 return; 175 } 176 ++state.data.top().container_element_index; 177 } 178 } 179 // if not, maybe it's a field of the current element 180 else { 181 // no change to ingredient_index 182 state.data.push(merge_check_point(expected_ingredient, 0)); 183 } 184 break; 185 } 186 // End check_merge_call Special-cases 187 default: { 188 if (!types_coercible(container, ingredients.at(ingredient_index))) { 189 raise << maybe(caller.name) << "incorrect type of ingredient " << ingredient_index << " in '" << to_original_string(inst) << "'\n" << end(); 190 raise << " (expected '" << debug_string(container) << "')\n" << end(); 191 raise << " (got '" << debug_string(ingredients.at(ingredient_index)) << "')\n" << end(); 192 return; 193 } 194 ++ingredient_index; 195 // ++state.data.top().container_element_index; // unnecessary, but wouldn't do any harm 196 do { 197 state.data.pop(); 198 if (state.data.empty()) { 199 if (ingredient_index < SIZE(ingredients)) 200 raise << maybe(caller.name) << "too many ingredients in '" << to_original_string(inst) << "'\n" << end(); 201 return; 202 } 203 ++state.data.top().container_element_index; 204 } while (state.data.top().container_element_index >= SIZE(get(Type, get_base_type(state.data.top().container.type)->value).elements)); 205 } 206 } 207 } 208 // never gets here 209 assert(false); 210 } 211 212 //: replaced in a later layer 213 //: todo: find some clean way to take this call completely out of this layer 214 const type_tree* get_base_type(const type_tree* t) { 215 return t; 216 } 217 218 :(scenario merge_check_product) 219 % Hide_errors = true; 220 def main [ 221 1:num <- merge 3 222 ] 223 +error: main: 'merge' should yield a container in '1:num <- merge 3' 224 225 :(before "End Includes") 226 #include <stack> 227 using std::stack;