Commit | Line | Data |
---|---|---|
03ac148f SK |
1 | %%%---------------------------------------------------------------------------- |
2 | %%% Equivalent to stdlib's orddict, but with a pretty (IMO), uniform interface. | |
3 | %%%---------------------------------------------------------------------------- | |
4 | -module(hope_kv_list). | |
5 | ||
6 | -behavior(hope_dictionary). | |
7 | ||
8 | -export_type( | |
9 | [ t/2 | |
10 | ]). | |
11 | ||
12 | -export( | |
13 | [ empty/0 | |
14 | , get/2 | |
15 | , set/3 | |
16 | , update/3 | |
70cf8e86 | 17 | , pop/2 |
03ac148f SK |
18 | , iter/2 |
19 | , map/2 | |
20 | , filter/2 | |
21 | , fold/3 | |
22 | , of_kv_list/1 | |
23 | , to_kv_list/1 | |
24 | ]). | |
25 | ||
26 | ||
27 | -type t(K, V) :: | |
28 | [{K, V}]. | |
29 | ||
30 | ||
31 | %% ============================================================================ | |
32 | %% API | |
33 | %% ============================================================================ | |
34 | ||
35 | -spec empty() -> | |
36 | []. | |
37 | empty() -> | |
38 | []. | |
39 | ||
40 | get(T, K) -> | |
41 | case lists:keyfind(K, 1, T) | |
42 | of false -> none | |
43 | ; {K, V} -> {some, V} | |
44 | end. | |
45 | ||
46 | set(T, K, V) -> | |
47 | lists:keystore(K, 1, T, {K, V}). | |
48 | ||
49 | update(T, K, F) -> | |
50 | V1Opt = get(T, K), | |
51 | V2 = F(V1Opt), | |
37c6e98b | 52 | % TODO: Eliminate the 2nd lookup. |
03ac148f SK |
53 | set(T, K, V2). |
54 | ||
70cf8e86 SK |
55 | pop(T1, K) -> |
56 | case lists:keytake(K, 1, T1) | |
57 | of {value, {K, V}, T2} -> {{some, V}, T2} | |
58 | ; false -> {none , T1} | |
59 | end. | |
60 | ||
c1672ac4 | 61 | iter(T, F1) -> |
d10156b0 | 62 | F2 = lift_map(F1), |
c1672ac4 | 63 | lists:foreach(F2, T). |
03ac148f | 64 | |
c1672ac4 | 65 | map(T, F1) -> |
d10156b0 SK |
66 | F2 = fun ({K, _}=X) -> {K, apply_map(F1, X)} end, |
67 | lists:map(F2, T). | |
03ac148f | 68 | |
c1672ac4 | 69 | filter(T, F1) -> |
d10156b0 | 70 | F2 = lift_map(F1), |
c1672ac4 | 71 | lists:filter(F2, T). |
03ac148f SK |
72 | |
73 | fold(T, F1, Accumulator) -> | |
74 | F2 = fun ({K, V}, Acc) -> F1(K, V, Acc) end, | |
75 | lists:foldl(F2, T, Accumulator). | |
76 | ||
77 | to_kv_list(T) -> | |
78 | T. | |
79 | ||
80 | of_kv_list(List) -> | |
37c6e98b | 81 | % TODO: Decide if validation is to be done here. Do so if yes. |
03ac148f SK |
82 | List. |
83 | ||
84 | ||
85 | %% ============================================================================ | |
86 | %% Helpers | |
87 | %% ============================================================================ | |
88 | ||
48371999 SK |
89 | -spec lift_map(F) -> |
90 | G | |
91 | when F :: fun(( K, V1 ) -> V2) | |
92 | , G :: fun(({K, V1}) -> V2) | |
93 | . | |
d10156b0 SK |
94 | lift_map(F) -> |
95 | fun (X) -> apply_map(F, X) end. | |
96 | ||
48371999 SK |
97 | -spec apply_map(fun((K, V1) -> V2), {K, V1}) -> |
98 | V2. | |
d10156b0 SK |
99 | apply_map(F, {K, V}) -> |
100 | F(K, V). |