1 //: Writing to a literal (not computed) address of 0 in a recipe chains two
  2 //: spaces together. When a variable has a property of /space:1, it looks up
  3 //: the variable in the chained/surrounding space. /space:2 looks up the
  4 //: surrounding space of the surrounding space, etc.
  5 
  6 :(scenario closure)
  7 def main [
  8   default-space:space <- new location:type, 30
  9   1:space/names:new-counter <- new-counter
 10   2:num/raw <- increment-counter 1:space/names:new-counter
 11   3:num/raw <- increment-counter 1:space/names:new-counter
 12 ]
 13 def new-counter [
 14   default-space:space <- new location:type, 30
 15   x:num <- copy 23
 16   y:num <- copy 3  # variable that will be incremented
 17   return default-space:space
 18 ]
 19 def increment-counter [
 20   default-space:space <- new location:type, 30
 21   0:space/names:new-counter <- next-ingredient  # outer space must be created by 'new-counter' above
 22   y:num/space:1 <- add y:num/space:1, 1  # increment
 23   y:num <- copy 234  # dummy
 24   return y:num/space:1
 25 ]
 26 +name: lexically surrounding space for recipe increment-counter comes from new-counter
 27 +mem: storing 5 in location 3
 28 
 29 //: To make this work, compute the recipe that provides names for the
 30 //: surrounding space of each recipe.
 31 
 32 :(before "End Globals")
 33 map<recipe_ordinal, recipe_ordinal> Surrounding_space;
 34 
 35 :(before "Transform.push_back(transform_names)")
 36 Transform.push_back(collect_surrounding_spaces);  // idempotent
 37 
 38 :(code)
 39 void collect_surrounding_spaces(const recipe_ordinal r) {
 40   trace(9991, "transform") << "--- collect surrounding spaces for recipe " << get(Recipe, r).name << end();
 41   for (int i = 0;  i < SIZE(get(Recipe, r).steps);  ++i) {
 42     const instruction& inst = get(Recipe, r).steps.at(i);
 43     if (inst.is_label) continue;
 44     for (int j = 0;  j < SIZE(inst.products);  ++j) {
 45       if (is_literal(inst.products.at(j))) continue;
 46       if (inst.products.at(j).name != "0") continue;
 47       if (!is_space(inst.products.at(j))) {
 48         raise << "slot 0 should always have type address:array:location, but is '" << to_string(inst.products.at(j)) << "'\n" << end();
 49         continue;
 50       }
 51       string_tree* s = property(inst.products.at(j), "names");
 52       if (!s) {
 53         raise << "slot 0 requires a /names property in recipe '" << get(Recipe, r).name << "'\n" << end();
 54         continue;
 55       }
 56       if (!s->atom) raise << "slot 0 should have a single value in /names, but got '" << to_string(inst.products.at(j)) << "'\n" << end();
 57       const string& surrounding_recipe_name = s->value;
 58       if (surrounding_recipe_name.empty()) {
 59         raise << "slot 0 doesn't initialize its /names property in recipe '" << get(Recipe, r).name << "'\n" << end();
 60         continue;
 61       }
 62       if (contains_key(Surrounding_space, r)
 63           && get(Surrounding_space, r) != get(Recipe_ordinal, surrounding_recipe_name)) {
 64         raise << "recipe '" << get(Recipe, r).name << "' can have only one 'surrounding' recipe but has '" << get(Recipe, get(Surrounding_space, r)).name << "' and '" << surrounding_recipe_name << "'\n" << end();
 65         continue;
 66       }
 67       trace(9993, "name") << "lexically surrounding space for recipe " << get(Recipe, r).name << " comes from " << surrounding_recipe_name << end();
 68       if (!contains_key(Recipe_ordinal, surrounding_recipe_name)) {
 69         raise << "can't find recipe providing surrounding space for '" << get(Recipe, r).name << "'; looking for '" << surrounding_recipe_name << "'\n" << end();
 70         continue;
 71       }
 72       put(Surrounding_space, r, get(Recipe_ordinal, surrounding_recipe_name));
 73     }
 74   }
 75 }
 76 
 77 //: Once surrounding spaces are available, transform_names uses them to handle
 78 //: /space properties.
 79 
 80 :(replace{} "int lookup_name(const reagent& r, const recipe_ordinal default_recipe)")
 81 int lookup_name(const reagent& x, const recipe_ordinal default_recipe) {
 82   if (!has_property(x, "space")) {
 83     if (Name[default_recipe].empty()) raise << "name not found: " << x.name << '\n' << end();
 84     return Name[default_recipe][x.name];
 85   }
 86   string_tree* p = property(x, "space");
 87   if (!p || !p->atom) raise << "/space property should have exactly one (non-negative integer) value\n" << end();
 88   int n = to_integer(p->value);
 89   assert(n >= 0);
 90   recipe_ordinal surrounding_recipe = lookup_surrounding_recipe(default_recipe, n);
 91   if (surrounding_recipe == -1) return -1;
 92   set<recipe_ordinal> done;
 93   vector<recipe_ordinal> path;
 94   return lookup_name(x, surrounding_recipe, done, path);
 95 }
 96 
 97 // If the recipe we need to lookup this name in doesn't have names done yet,
 98 // recursively call transform_names on it.
 99 int lookup_name(const reagent& x, const recipe_ordinal r, set<recipe_ordinal>& done, vector<recipe_ordinal>& path) {
100   if (!Name[r].empty()) return Name[r][x.name];
101   if (contains_key(done, r)) {
102     raise << "can't compute address of '" << to_string(x) << "' because\n" << end();
103     for (int i = 1;  i < SIZE(path);  ++i) {
104       raise << path.at(i-1) << " requires computing names of " << path.at(i) << '\n' << end();
105     }
106     raise << path.at(SIZE(path)-1) << " requires computing names of " << r << "..ad infinitum\n" << end();
107     return -1;
108   }
109   done.insert(r);
110   path.push_back(r);
111   transform_names(r);  // Not passing 'done' through. Might this somehow cause an infinite loop?
112   assert(!Name[r].empty());
113   return Name[r][x.name];
114 }
115 
116 recipe_ordinal lookup_surrounding_recipe(const recipe_ordinal r, int n) {
117   if (n == 0) return r;
118   if (!contains_key(Surrounding_space, r)) {
119     raise << "don't know surrounding recipe of '" << get(Recipe, r).name << "'\n" << end();
120     return -1;
121   }
122   assert(contains_key(Surrounding_space, r));
123   return lookup_surrounding_recipe(get(Surrounding_space, r), n-1);
124 }
125 
126 //: weaken use-before-set detection just a tad
127 :(replace{} "bool already_transformed(const reagent& r, const map<string, int>& names)")
128 bool already_transformed(const reagent& r, const map<string, int>& names) {
129   if (has_property(r, "space")) {
130     string_tree* p = property(r, "space");
131     if (!p || !p->atom) {
132       raise << "/space property should have exactly one (non-negative integer) value in '" << r.original_string << "'\n" << end();
133       return false;
134     }
135     if (p->value != "0") return true;
136   }
137   return contains_key(names, r.name);
138 }
139 
140 :(scenario missing_surrounding_space)
141 % Hide_errors = true;
142 def f [
143   local-scope
144   x:num/space:1 <- copy 34
145 ]
146 +error: don't know surrounding recipe of 'f'
147 +error: f: can't find a place to store 'x'
148 
149 //: extra test for try_reclaim_locals() from previous layers
150 :(scenario local_scope_ignores_nonlocal_spaces)
151 def new-scope [
152   new-default-space
153   x:&:num <- new number:type
154   *x:&:num <- copy 34
155   return default-space:space
156 ]
157 def use-scope [
158   local-scope
159   outer:space <- next-ingredient
160   0:space/names:new-scope <- copy outer:space
161   return *x:&:num/space:1
162 ]
163 def main [
164   1:space/raw <- new-scope
165   2:num/raw <- use-scope 1:space/raw
166 ]
167 +mem: storing 34 in location 2