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

module(location).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% TYPES %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
type type() :: {non_neg_integer(), non_neg_integer()}.
export_type([type/0]).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% EXPORTS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
export
(
[
decode/1,
encode/1
]
).
export
(
[
apply_direction/2,
dist/2
]
).
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% LOCAL FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
spec validate ({integer(), integer()}) > type().
validate ({X, Y}) >
true = (X >= 0),
true = (Y >= 0),
{X, Y}.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% EXPORTED FUNCTIONS %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
spec apply_direction (direction:enum(), type()) > type().
apply_direction (left, {X, Y}) >
validate({(X  1), Y});
apply_direction (right, {X, Y}) >
validate({(X + 1), Y});
apply_direction (up, {X, Y}) >
validate({X, (Y  1)});
apply_direction (down, {X, Y}) >
validate({X, (Y + 1)}).
spec dist(type(), type()) > non_neg_integer().
dist ({OX, OY}, {DX, DY}) >
(abs(DY  OY) + abs(DX  OX)).
spec encode (type()) > {list(any())}.
encode ({X, Y}) >
{
[
{<<"x">>, X},
{<<"y">>, Y}
]
}.
spec decode (map()) > type().
decode (Map) >
X = maps:get(<<"x">>, Map),
Y = maps:get(<<"y">>, Map),
true = (is_integer(X) and is_integer(Y)),
validate({X, Y}).
