1 //: Let's raise errors when students use real hardware in any recipes besides
 2 //: 'main'. Part of the goal is to teach them testing hygiene and dependency
 3 //: injection.
 4 //:
 5 //: This is easy to sidestep, it's for feedback rather than safety.
 6 
 7 :(before "End Globals")
 8 vector<type_tree*> Real_hardware_types;
 9 :(before "Begin transform_all")
10 setup_real_hardware_types();
11 :(before "End transform_all")
12 teardown_real_hardware_types();
13 :(code)
14 void setup_real_hardware_types() {
15   Real_hardware_types.push_back(parse_type("address:screen"));
16   Real_hardware_types.push_back(parse_type("address:console"));
17   Real_hardware_types.push_back(parse_type("address:resources"));
18 }
19 type_tree* parse_type(string s) {
20   reagent x("x:"+s);
21   type_tree* result = x.type;
22   x.type = NULL;  // don't deallocate on return
23   return result;
24 }
25 void teardown_real_hardware_types() {
26   for (int i = 0;  i < SIZE(Real_hardware_types);  ++i)
27     delete Real_hardware_types.at(i);
28   Real_hardware_types.clear();
29 }
30 
31 :(before "End Checks")
32 Transform.push_back(check_for_misuse_of_real_hardware);
33 :(code)
34 void check_for_misuse_of_real_hardware(const recipe_ordinal r) {
35   const recipe& caller = get(Recipe, r);
36   if (caller.name == "main") return;
37   if (starts_with(caller.name, "scenario_")) return;
38   trace(9991, "transform") << "--- check if recipe " << caller.name << " has any dependency-injection mistakes" << end();
39   for (int index = 0;  index < SIZE(caller.steps);  ++index) {
40     const instruction& inst = caller.steps.at(index);
41     if (is_primitive(inst.operation)) continue;
42     for (int i = 0;  i < SIZE(inst.ingredients);  ++i) {
43       const reagent& ing = inst.ingredients.at(i);
44       if (!is_literal(ing) || ing.name != "0") continue;
45       const recipe& callee = get(Recipe, inst.operation);
46       if (!callee.has_header) continue;
47       if (i >= SIZE(callee.ingredients)) continue;
48       const reagent& expected_ing = callee.ingredients.at(i);
49       for (int j = 0;  j < SIZE(Real_hardware_types);  ++j) {
50         if (*Real_hardware_types.at(j) == *expected_ing.type)
51           raise << maybe(caller.name) << "'" << to_original_string(inst) << "': only 'main' can pass 0 into a " << to_string(expected_ing.type) << '\n' << end();
52       }
53     }
54   }
55 }
56 
57 :(scenarios transform)
58 :(scenario warn_on_using_real_screen_directly_in_non_main_recipe)
59 % Hide_errors = true;
60 def foo [
61   print 0, 34
62 ]
63 +error: foo: 'print 0, 34': only 'main' can pass 0 into a (address screen)