about summary refs log tree commit diff stats
path: root/033exclusive_container.cc
blob: e2f520f8bb36039ffb2489d68b7a66e0bc1966f6 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
//: Exclusive containers contain exactly one of a fixed number of 'variants'
//: of different types.
//:
//: They also implicitly contain a tag describing precisely which variant is
//: currently stored in them.

:(before "End Mu Types Initialization")
//: We'll use this container as a running example, with two number elements.
{
type_ordinal tmp = Type_ordinal["number-or-point"] = Next_type_ordinal++;
Type[tmp].size = 2;
Type[tmp].kind = exclusive_container;
Type[tmp].name = "number-or-point";
vector<type_ordinal> t1;
t1.push_back(number);
Type[tmp].elements.push_back(t1);
vector<type_ordinal> t2;
t2.push_back(point);
Type[tmp].elements.push_back(t2);
Type[tmp].element_names.push_back("i");
Type[tmp].element_names.push_back("p");
}

//: Tests in this layer often explicitly setup memory before reading it as an
//: array. Don't do this in general. I'm tagging exceptions with /raw to
//: avoid warnings.
:(scenario copy_exclusive_container)
# Copying exclusive containers copies all their contents and an extra location for the tag.
recipe main [
  1:number <- copy 1  # 'point' variant
  2:number <- copy 34
  3:number <- copy 35
  4:number-or-point <- copy 1:number-or-point/raw  # unsafe
]
+mem: storing 1 in location 4
+mem: storing 34 in location 5
+mem: storing 35 in location 6

:(before "End size_of(types) Cases")
if (t.kind == exclusive_container) {
  // size of an exclusive container is the size of its largest variant
  // (So like containers, it can't contain arrays.)
  long long int result = 0;
  for (long long int i = 0; i < t.size; ++i) {
    long long int tmp = size_of(t.elements.at(i));
    if (tmp > result) result = tmp;
  }
  // ...+1 for its tag.
  return result+1;
}

//:: To access variants of an exclusive container, use 'maybe-convert'.
//: It always returns an address (so that you can modify it) or null (to
//: signal that the conversion failed (because the container contains a
//: different variant).

//: 'maybe-convert' requires a literal in ingredient 1. We'll use a synonym
//: called 'variant'.
:(before "End Mu Types Initialization")
Type_ordinal["variant"] = 0;

:(scenario maybe_convert)
recipe main [
  12:number <- copy 1
  13:number <- copy 35
  14:number <- copy 36
  20:address:point <- maybe-convert 12:number-or-point/raw, 1:variant  # unsafe
]
+mem: storing 13 in location 20

:(scenario maybe_convert_fail)
recipe main [
  12:number <- copy 1
  13:number <- copy 35
  14:number <- copy 36
  20:address:point <- maybe-convert 12:number-or-point/raw, 0:variant  # unsafe
]
+mem: storing 0 in location 20

:(before "End Primitive Recipe Declarations")
MAYBE_CONVERT,
:(before "End Primitive Recipe Numbers")
Recipe_ordinal["maybe-convert"] = MAYBE_CONVERT;
:(before "End Primitive Recipe Implementations")
case MAYBE_CONVERT: {
  if (SIZE(ingredients) != 2) {
    raise << current_recipe_name() << ": 'maybe-convert' expects exactly 2 ingredients in '" << current_instruction().to_string() << "'\n" << end();
    break;
  }
  reagent base = canonize(current_instruction().ingredients.at(0));
  long long int base_address = base.value;
  if (base_address == 0) {
    raise << current_recipe_name() << ": tried to access location 0 in '" << current_instruction().to_string() << "'\n" << end();
    break;
  }
  type_ordinal base_type = base.types.at(0);
  if (Type[base_type].kind != exclusive_container) {
    raise << current_recipe_name () << ": first ingredient of 'maybe-convert' should be an exclusive-container, but got " << base.original_string << '\n' << end();
    break;
  }
  if (!is_literal(current_instruction().ingredients.at(1))) {
    raise << current_recipe_name() << ": second ingredient of 'maybe-convert' should have type 'variant', but got " << current_instruction().ingredients.at(1).original_string << '\n' << end();
    break;
  }
  long long int tag = current_instruction().ingredients.at(1).value;
  long long int result;
  if (tag == static_cast<long long int>(Memory[base_address])) {
    result = base_address+1;
  }
  else {
    result = 0;
  }
  products.resize(1);
  products.at(0).push_back(result);
  break;
}

//:: Allow exclusive containers to be defined in mu code.

:(scenario exclusive_container)
exclusive-container foo [
  x:number
  y:number
]
+parse: reading exclusive-container foo
+parse:   element name: x
+parse:   type: 1
+parse:   element name: y
+parse:   type: 1

:(before "End Command Handlers")
else if (command == "exclusive-container") {
  insert_container(command, exclusive_container, in);
}

//:: To construct exclusive containers out of variant types, use 'merge'.
:(scenario lift_to_exclusive_container)
exclusive-container foo [
  x:number
  y:number
]

recipe main [
  1:number <- copy 34
  2:foo <- merge 0/x, 1:number
  4:foo <- merge 1/x, 1:number
]
+mem: storing 0 in location 2
+mem: storing 34 in location 3
+mem: storing 1 in location 4
+mem: storing 34 in location 5