1 files changed, 142 insertions, 0 deletions
diff --git a/cpp/020array b/cpp/020array
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+//: Support for arrays.
+:(before "End Mu Types Initialization")
+//: We'll use this array as a running example:
+int integer_array = Type_number["integer-array"] = Next_type_number++;
+Type[integer_array].is_array = true;
+Type[integer_array].element.push_back(integer);
+
+//: Arrays can be copied around with a single instruction just like integers,
+//: no matter how large they are.
+
+:(scenario copy_array)
+recipe main [
+  1:integer <- copy 3:literal
+  2:integer <- copy 14:literal
+  3:integer <- copy 15:literal
+  4:integer <- copy 16:literal
+  5:integer-array <- copy 1:integer-array
+]
++run: instruction main/4
++run: ingredient 0 is 1
++mem: location 1 is 3
++mem: location 2 is 14
++mem: location 3 is 15
++mem: location 4 is 16
++mem: storing in location 5
++mem: storing in location 6
++mem: storing in location 7
++mem: storing in location 8
+
+:(replace{} "size_t size_of(reagent r)")
+size_t size_of(reagent r) {
+  type_info t = Type[r.types[0]];
+  if (t.is_record) {
+    int result = 0;
+    for (size_t i = 0; i < t.size; ++i) {
+      ostringstream out;
+      out << result;
+      reagent x(out.str());
+      copy(t.elements[i].begin(), t.elements[i].end(), inserter(x.types, x.types.begin()));
+      result += size_of(x);
+    }
+    return result;
+  }
+  if (t.is_array) {
+    assert(!r.name.empty());
+    int base = to_int(r.name);
+    if (Memory[base] == 0) return 0;
+    ostringstream out;
+    out << base+1;
+    reagent x(out.str());
+    x.types.push_back(t.element[0]);
+    return 1 + Memory[base]*size_of(x);
+  }
+  // scalar
+  return t.size;
+}
+
+:(before "End Globals")
+// Operator to look at elements of arrays.
+const int INDEX = 20;
+:(before "End Primitive Recipe Numbers")
+Recipe_number["index"] = INDEX;
+assert(Next_recipe_number == INDEX);
+Next_recipe_number++;
+:(before "End Primitive Recipe Implementations")
+case INDEX: {
+  trace("run") << "ingredient 0 is " << instructions[pc].ingredients[0].name;
+  reagent base = canonize(instructions[pc].ingredients[0]);
+  int base_address = to_int(base.name);
+  int base_type = base.types[0];
+  assert(Type[base_type].is_array);
+  trace("run") << "ingredient 1 is " << instructions[pc].ingredients[1].name;
+  size_t offset = to_int(instructions[pc].ingredients[1].name);
+  int src = base_address + 1 + offset*size_of(reagent(Type[base_type].element[0]));
+  trace("run") << "address to copy is " << src;
+  int src_type = Type[base_type].element[0];
+  trace("run") << "its type is " << src_type;
+  ostringstream s;
+  s << src;
+  reagent tmp(s.str());
+  tmp.types.push_back(src_type);
+  vector<int> result(read_memory(tmp));
+  trace("run") << "product 0 is " << result[0];
+  write_memory(instructions[pc].products[0], result);
+  break;
+}
+
+:(scenario "index")
+recipe main [
+  1:integer <- copy 3:literal
+  2:integer <- copy 14:literal
+  3:integer <- copy 15:literal
+  4:integer <- copy 16:literal
+  5:integer <- index 1:integer-array, 0:literal
+]
++run: instruction main/4
++run: ingredient 0 is 1
++run: ingredient 1 is 0
++run: address to copy is 2
++run: its type is 1
++mem: location 2 is 14
++run: product 0 is 14
++mem: storing in location 5
+
+:(before "End Globals")
+// To write to fields of records, you need their address.
+const int INDEX_ADDRESS = 21;
+:(before "End Primitive Recipe Numbers")
+Recipe_number["index-address"] = INDEX_ADDRESS;
+assert(Next_recipe_number == INDEX_ADDRESS);
+Next_recipe_number++;
+:(before "End Primitive Recipe Implementations")
+case INDEX_ADDRESS: {
+  trace("run") << "ingredient 0 is " << instructions[pc].ingredients[0].name;
+  reagent base = canonize(instructions[pc].ingredients[0]);
+  int base_address = to_int(base.name);
+  int base_type = base.types[0];
+  assert(Type[base_type].is_array);
+  trace("run") << "ingredient 1 is " << instructions[pc].ingredients[1].name;
+  size_t offset = to_int(instructions[pc].ingredients[1].name);
+  int src = base_address + 1 + offset*size_of(reagent(Type[base_type].element[0]));
+  trace("run") << "address to copy is " << src;
+  vector<int> result;
+  result.push_back(src);
+  trace("run") << "product 0 is " << result[0];
+  write_memory(instructions[pc].products[0], result);
+  break;
+}
+
+:(scenario "index_address")
+recipe main [
+  1:integer <- copy 3:literal
+  2:integer <- copy 14:literal
+  3:integer <- copy 15:literal
+  4:integer <- copy 16:literal
+  5:integer <- index-address 1:integer-array, 0:literal
+]
++run: instruction main/4
++run: ingredient 0 is 1
++run: ingredient 1 is 0
++run: address to copy is 2
++mem: storing in location 5