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
|
namespace Eva {
public class List : Object, Term {
private static List _empty;
private Term? _head;
private Term? _tail;
public static List empty {
get {
if(_empty == null)
_empty = new List.create_empty();
return _empty;
}
}
public Term head {
get {
assert(!is_empty);
return _head;
}
}
public Term tail {
get {
assert(!is_empty);
return _tail;
}
}
public bool is_empty {
get {
if(this == _empty) {
assert(_head == null && _tail == null);
return true;
}
else {
assert(_head != null && _tail != null);
return false;
}
}
}
public List(Term head0, Term tail0 = empty) {
_head = head0;
_tail = tail0;
}
private List.create_empty() {
_head = null;
_tail = null;
}
public static List from_list(Gee.List<Term> list) {
if(list.is_empty)
return empty;
else
return new List(list.first(), List.from_list(list[1:list.size]));
}
protected bool do_match(Term o, Gee.Map<string, Term> vars, Gee.Map<string, string> aliases) {
if(o is Var) {
return o.do_match(this, vars, aliases);
}
if(o is List) {
List l = o as List;
if(is_empty && l.is_empty)
return true;
if(is_empty && !l.is_empty)
return false;
if(!is_empty && l.is_empty)
return false;
return (_head.do_match(l.head, vars, aliases) && _tail.do_match(l.tail, vars, aliases));
}
else if(o is String) {
return do_match(string_to_list((o as String).value), vars, aliases);
}
else {
return false;
}
}
public string to_string() {
if(is_empty)
return "[]";
string ret = "[" + _head.to_string();
Term rest = _tail;
for(rest = _tail; rest is List && rest != List.empty; rest = (rest as List)._tail) {
ret += "," + (rest as List)._head.to_string();
}
if(rest != List.empty) {
ret += "|" + rest.to_string();
}
return ret + "]";
}
public void encode(Erl.Buffer buffer) {
if(is_empty) {
buffer.encode_empty_list();
}
else {
buffer.encode_list_header(1);
_head.encode(buffer);
_tail.encode(buffer);
}
}
}
}
|
