_site/cover/narcs_combinator.COVER.html

1 %% Copyright (c) 2023 Peter Morgan <peter.james.morgan@gmail.com>
2 %%
3 %% Licensed under the Apache License, Version 2.0 (the "License");
4 %% you may not use this file except in compliance with the License.
5 %% You may obtain a copy of the License at
6 %%
7 %% http://www.apache.org/licenses/LICENSE-2.0
8 %%
9 %% Unless required by applicable law or agreed to in writing, software
10 %% distributed under the License is distributed on an "AS IS" BASIS,
11 %% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 %% See the License for the specific language governing permissions and
13 %% limitations under the License.
14
15
16 %% @doc Encoder combinators.
17
18 -module(narcs_combinator).
19
20
21 -export([condition/2]).
22 -export([map_result/2]).
23 -export([rest/0]).
24 -export([v/2]).
25 -include_lib("kernel/include/logger.hrl").
26
27
28 %% @doc Map the result of the supplied encoder.
29
30 map_result(Encoder, Mapping) ->
31 9 fun
32 (Decoded) ->
33 6 (Mapping(Encoder(Decoded)))
34 end.
35
36
37 %% @doc Apply the encoder if the condition is true.
38
39 -type condition() :: boolean()
40 | atom().
41
42 -spec condition(condition(), narcs:encoder()) -> narcs:encoder().
43
44 condition(true, Encoder) ->
45
:-(
fun
46 (Decoded) ->
47
:-(
(Encoder)(Decoded)
48 end;
49
50 condition(false, _) ->
51
:-(
fun
52 (_) ->
53
:-(
<<>>
54 end;
55
56 condition(Key, Encoder) ->
57 1 fun
58 (#{Key := true} = Decoded) ->
59 1 (Encoder)(Decoded);
60
61 (#{Key := false}) ->
62 1 <<>>;
63
64 (_) ->
65
:-(
error(badarg, [Key, Encoder])
66 end.
67
68
69 %% @doc Apply an encoder on the value represented by the supplied key.
70
71 -spec v(any(), narcs:encoder()) -> narcs:encoder(map(), narcs:output()).
72
73 v(Key, Encoder) ->
74 8 fun
75 (#{Key := Value} = Decoded) ->
76 4 ?LOG_DEBUG(#{key => Key, value => Value, decoded => Decoded}),
77 4 Encoder(Value);
78
79 (_) ->
80
:-(
error(badarg, [Key, Encoder])
81 end.
82
83
84 %% @doc Use the rest of the output as is.
85
86 -spec rest() -> narcs:encoder().
87
88 rest() ->
89
:-(
fun
90 (Decoded) ->
91
:-(
Decoded
92 end.
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