forked from VictorTaelin/abstract-algorithm
-
Notifications
You must be signed in to change notification settings - Fork 0
/
inet.js
188 lines (176 loc) · 4.93 KB
/
inet.js
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
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
const Name = require("./name.js");
const New = (ctor, kind) => ({ctor, port: [null, null, null], kind: kind||{}});
const Ptr = (node, slot) => ({ctor: "Ptr", node, slot});
// Stringifies an interaction net.
// The syntax used denotes one node per line. A line starts with "-" for a Lam
// node, and "+" for a Let node. It is followed by 3 write names. Example:
// - a b b
// - a c c
// Represents a net with two nodes connected by their main ports:
// __________
// | a |
// / \ / \
// |'''| |'''|
// |___| |___|
// b c
function show(inet) {
var text = "";
var numb = 0;
var link = {};
for (var node in inet) {
text += inet[node].ctor === "Lam" ? "- " : "+ ";
for (var slot = 0; slot < 3; ++slot) {
var self_id = node+"-"+slot;
if (equal(inet[node].port[slot], Ptr(node, slot))) {
text += "- ";
} else {
var neig_id = inet[node].port[slot].node+"-"+inet[node].port[slot].slot;
if (link[neig_id]) {
text += link[neig_id] + " ";
} else {
link[self_id] = Name.rank(numb++);
text += link[self_id] + " ";
}
}
}
text += "\n";
};
return text.slice(0,-1);
};
// Parses a string as an interaction net.
function read(code) {
var lines = code.split("\n").filter(x => x !== "");
var link = {};
var inet = {};
for (var node = 0; node < lines.length; ++node) {
var node = String(node);
var kind = lines[node][0];
var vars = lines[node].slice(2).split(" ");
inet[node] = New(kind === "-" ? "Lam" : kind === "+" ? "Let" : Name.fresh());
for (var slot = 0; slot < 3; ++slot) {
var name = vars[slot];
if (name === "-") {
inet[node].port[slot] = Ptr(node, slot);
} else if (!link[name]) {
link[name] = Ptr(node, slot);
} else {
inet[node].port[slot] = link[name];
inet[link[name].node].port[link[name].slot] = Ptr(node, slot);
}
}
};
return inet;
};
// Are two pointers the same?
function equal(a, b) {
return b !== null && a.node === b.node && a.slot === b.slot;
}
// Gets the other side of a pointer
function enter(inet, ptr) {
if (inet[ptr.node] !== null) {
//console.log(inet, ptr.node);
return inet[ptr.node].port[ptr.slot];
} else {
return null;
}
};
// Links two ports
function link(inet, a_ptr, b_ptr) {
if (a_ptr) {
inet[a_ptr.node].port[a_ptr.slot] = b_ptr;
}
if (b_ptr) {
inet[b_ptr.node].port[b_ptr.slot] = a_ptr;
}
}
// Unlinks a port (neighbor will point to itself)
function unlink(inet, a_ptr) {
var b_ptr = enter(inet, a_ptr);
if (equal(a_ptr, enter(inet, b_ptr))) {
inet[a_ptr.node].port[a_ptr.slot] = a_ptr;
inet[b_ptr.node].port[b_ptr.slot] = b_ptr;
}
}
// Applies the annihilate rewrite rule
function annihilate(inet, a, b) {
var a_dest1 = enter(inet, Ptr(a, 1));
var b_dest1 = enter(inet, Ptr(b, 1));
link(inet, a_dest1, b_dest1);
var a_dest2 = enter(inet, Ptr(a, 2));
var b_dest2 = enter(inet, Ptr(b, 2));
link(inet, a_dest2, b_dest2);
}
// Applies the commute rewrite rule
function commute(inet, a, b) {
var p = Name.fresh();
var q = Name.fresh();
var r = Name.fresh();
var s = Name.fresh();
inet[p] = New(inet[b].ctor, inet[b].kind);
inet[q] = New(inet[b].ctor, inet[b].kind);
inet[r] = New(inet[a].ctor, inet[a].kind);
inet[s] = New(inet[a].ctor, inet[a].kind);
link(inet, Ptr(r, 1), Ptr(p, 1));
link(inet, Ptr(s, 1), Ptr(p, 2));
link(inet, Ptr(r, 2), Ptr(q, 1));
link(inet, Ptr(s, 2), Ptr(q, 2));
link(inet, Ptr(p, 0), enter(inet, Ptr(a, 1)));
link(inet, Ptr(q, 0), enter(inet, Ptr(a, 2)));
link(inet, Ptr(r, 0), enter(inet, Ptr(b, 1)));
link(inet, Ptr(s, 0), enter(inet, Ptr(b, 2)));
}
// Applies a single pairwise rewrite
function rewrite(inet, a, b) {
if (inet[a].ctor === inet[b].ctor) {
annihilate(inet, a, b);
} else {
commute(inet, a, b);
}
// Makes sure there aren't leftover pointers to rewritten nodes
for (var i = 0; i < 3; i++) {
unlink(inet, Ptr(a, i));
unlink(inet, Ptr(b, i));
}
// Deletes rewritten nodes
delete inet[a];
delete inet[b];
};
// Reduces a net to normal form lazily
// Returns number of rewrites
function reduce(inet) {
var warp = [];
var exit = [];
var next = enter(inet, Ptr("0", 1));
var prev = null;
var back = null;
var rwts = 0;
while (next.node !== "0" || warp.length > 0) {
next = next.node === "0" ? enter(inet, warp.pop()) : next;
prev = enter(inet, next);
if (next.slot === 0 && prev.slot === 0) {
back = enter(inet, Ptr(prev.node, exit.pop()));
rewrite(inet, prev.node, next.node);
next = enter(inet, back);
++rwts;
} else if (next.slot === 0) {
warp.push(Ptr(next.node, 2));
next = enter(inet, Ptr(next.node, 1));
} else {
exit.push(next.slot);
next = enter(inet, Ptr(next.node, 0));
}
}
return rwts;
}
module.exports = {
New,
Ptr,
show,
read,
equal,
enter,
link,
unlink,
rewrite,
reduce,
};