1 //: Introduce a new transform to perform various checks in instructions before
  2 //: we start running them. It'll be extensible, so that we can add checks for
  3 //: new recipes as we extend 'run' to support them.
  4 //:
  5 //: Doing checking in a separate part complicates things, because the values
  6 //: of variables in memory and the processor (current_recipe_name,
  7 //: current_instruction) aren't available at checking time. If I had a more
  8 //: sophisticated layer system I'd introduce the simpler version first and
  9 //: transform it in a separate layer or set of layers.
 10 
 11 :(before "End Checks")
 12 Transform.push_back(check_instruction);  // idempotent
 13 
 14 :(code)
 15 void check_instruction(const recipe_ordinal r) {
 16   trace(9991, "transform") << "--- perform checks for recipe " << get(Recipe, r).name << end();
 17   map<string, vector<type_ordinal> > metadata;
 18   for (int i = 0;  i < SIZE(get(Recipe, r).steps);  ++i) {
 19     instruction& inst = get(Recipe, r).steps.at(i);
 20     if (inst.is_label) continue;
 21     switch (inst.operation) {
 22       // Primitive Recipe Checks
 23       case COPY: {
 24         if (SIZE(inst.products) != SIZE(inst.ingredients)) {
 25           raise << maybe(get(Recipe, r).name) << "ingredients and products should match in '" << inst.original_string << "'\n" << end();
 26           break;
 27         }
 28         for (int i = 0;  i < SIZE(inst.ingredients);  ++i) {
 29           if (!types_coercible(inst.products.at(i), inst.ingredients.at(i))) {
 30             raise << maybe(get(Recipe, r).name) << "can't copy '" << inst.ingredients.at(i).original_string << "' to '" << inst.products.at(i).original_string << "'; types don't match\n" << end();
 31             goto finish_checking_instruction;
 32           }
 33         }
 34         break;
 35       }
 36       // End Primitive Recipe Checks
 37       default: {
 38         // Defined Recipe Checks
 39         // End Defined Recipe Checks
 40       }
 41     }
 42     finish_checking_instruction:;
 43   }
 44 }
 45 
 46 :(scenario copy_checks_reagent_count)
 47 % Hide_errors = true;
 48 def main [
 49   1:num <- copy 34, 35
 50 ]
 51 +error: main: ingredients and products should match in '1:num <- copy 34, 35'
 52 
 53 :(scenario write_scalar_to_array_disallowed)
 54 % Hide_errors = true;
 55 def main [
 56   1:array:num <- copy 34
 57 ]
 58 +error: main: can't copy '34' to '1:array:num'; types don't match
 59 
 60 :(scenario write_scalar_to_array_disallowed_2)
 61 % Hide_errors = true;
 62 def main [
 63   1:num, 2:array:num <- copy 34, 35
 64 ]
 65 +error: main: can't copy '35' to '2:array:num'; types don't match
 66 
 67 :(scenario write_scalar_to_address_disallowed)
 68 % Hide_errors = true;
 69 def main [
 70   1:address:num <- copy 34
 71 ]
 72 +error: main: can't copy '34' to '1:address:num'; types don't match
 73 
 74 :(scenario write_address_to_number_allowed)
 75 def main [
 76   1:address:num <- copy 12/unsafe
 77   2:num <- copy 1:address:num
 78 ]
 79 +mem: storing 12 in location 2
 80 $error: 0
 81 
 82 :(scenario write_boolean_to_number_allowed)
 83 def main [
 84   1:bool <- copy 1/true
 85   2:num <- copy 1:bool
 86 ]
 87 +mem: storing 1 in location 2
 88 $error: 0
 89 
 90 :(scenario write_number_to_boolean_allowed)
 91 def main [
 92   1:num <- copy 34
 93   2:bool <- copy 1:num
 94 ]
 95 +mem: storing 34 in location 2
 96 $error: 0
 97 
 98 :(code)
 99 // types_match with some leniency
100 bool types_coercible(const reagent& to, const reagent& from) {
101   if (types_match(to, from)) return true;
102   if (is_mu_address(from) && is_mu_number(to)) return true;
103   if (is_mu_boolean(from) && is_mu_number(to)) return true;
104   if (is_mu_number(from) && is_mu_boolean(to)) return true;
105   // End types_coercible Special-cases
106   return false;
107 }
108 
109 bool types_match(const reagent& to, const reagent& from) {
110   // to sidestep type-checking, use /unsafe in the source.
111   // this will be highlighted in red inside vim. just for setting up some tests.
112   if (is_unsafe(from)) return true;
113   if (is_literal(from)) {
114     if (is_mu_array(to)) return false;
115     // End Matching Types For Literal(to)
116     // allow writing 0 to any address
117     if (is_mu_address(to)) return from.name == "0";
118     if (!to.type) return false;
119     if (to.type->atom && to.type->value == get(Type_ordinal, "boolean"))
120       return from.name == "0" || from.name == "1";
121     return size_of(to) == 1;  // literals are always scalars
122   }
123   return types_strictly_match(to, from);
124 }
125 
126 //: copy arguments for later layers
127 bool types_strictly_match(reagent/*copy*/ to, reagent/*copy*/ from) {
128   // End Preprocess types_strictly_match(reagent to, reagent from)
129   if (is_literal(from) && to.type->value == get(Type_ordinal, "number")) return true;
130   // to sidestep type-checking, use /unsafe in the source.
131   // this will be highlighted in red inside vim. just for setting up some tests.
132   if (is_unsafe(from)) return true;
133   // '_' never raises type error
134   if (is_dummy(to)) return true;
135   if (!to.type) return !from.type;
136   return types_strictly_match(to.type, from.type);
137 }
138 
139 bool types_strictly_match(const type_tree* to, const type_tree* from) {
140   if (from == to) return true;
141   if (!to) return false;
142   if (!from) return to->atom && to->value == 0;
143   if (from->atom != to->atom) return false;
144   if (from->atom) {
145     if (from->value == -1) return from->name == to->name;
146     return from->value == to->value;
147   }
148   return types_strictly_match(to->left, from->left) && types_strictly_match(to->right, from->right);
149 }
150 
151 void test_unknown_type_does_not_match_unknown_type() {
152   reagent a("a:foo");
153   reagent b("b:bar");
154   CHECK(!types_strictly_match(a, b));
155 }
156 
157 void test_unknown_type_matches_itself() {
158   reagent a("a:foo");
159   reagent b("b:foo");
160   CHECK(types_strictly_match(a, b));
161 }
162 
163 //: helpers
164 
165 bool is_unsafe(const reagent& r) {
166   return has_property(r, "unsafe");
167 }
168 
169 bool is_mu_array(reagent/*copy*/ r) {
170   // End Preprocess is_mu_array(reagent r)
171   return is_mu_array(r.type);
172 }
173 bool is_mu_array(const type_tree* type) {
174   if (!type) return false;
175   if (is_literal(type)) return false;
176   if (type->atom) return false;
177   if (!type->left->atom) {
178     raise << "invalid type " << to_string(type) << '\n' << end();
179     return false;
180   }
181   return type->left->value == get(Type_ordinal, "array");
182 }
183 
184 bool is_mu_address(reagent/*copy*/ r) {
185   // End Preprocess is_mu_address(reagent r)
186   return is_mu_address(r.type);
187 }
188 bool is_mu_address(const type_tree* type) {
189   if (!type) return false;
190   if (is_literal(type)) return false;
191   if (type->atom) return false;
192   if (!type->left->atom) {
193     raise << "invalid type " << to_string(type) << '\n' << end();
194     return false;
195   }
196   return type->left->value == get(Type_ordinal, "address");
197 }
198 
199 bool is_mu_boolean(reagent/*copy*/ r) {
200   // End Preprocess is_mu_boolean(reagent r)
201   if (!r.type) return false;
202   if (is_literal(r)) return false;
203   if (!r.type->atom) return false;
204   return r.type->value == get(Type_ordinal, "boolean");
205 }
206 
207 bool is_mu_number(reagent/*copy*/ r) {
208   // End Preprocess is_mu_number(reagent r)
209   if (!r.type) return false;
210   if (!r.type->atom) return false;
211   if (is_literal(r)) {
212     return r.type->name == "literal-fractional-number"
213         || r.type->name == "literal";
214   }
215   if (r.type->value == get(Type_ordinal, "character")) return true;  // permit arithmetic on unicode code points
216   return r.type->value == get(Type_ordinal, "number");
217 }
218 
219 bool is_mu_character(reagent/*copy*/ r) {
220   // End Preprocess is_mu_character(reagent r)
221   return is_mu_character(r.type);
222 }
223 bool is_mu_character(const type_tree* type) {
224   if (!type) return false;
225   if (!type->atom) return false;
226   if (is_literal(type)) return false;
227   return type->value == get(Type_ordinal, "character");
228 }
229 
230 bool is_mu_scalar(reagent/*copy*/ r) {
231   return is_mu_scalar(r.type);
232 }
233 bool is_mu_scalar(const type_tree* type) {
234   if (!type) return false;
235   if (is_mu_address(type)) return true;
236   if (!type->atom) return false;
237   if (is_literal(type))
238     return type->name != "literal-string";
239   return size_of(type) == 1;
240 }