Commit | Line | Data |
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6731749b SK |
1 | -module(hope_result). |
2 | ||
b69220d7 | 3 | -behavior(hope_gen_monad). |
2a40de4f | 4 | |
3b156801 SK |
5 | -export_type( |
6 | [ t/2 | |
7 | ]). | |
6731749b | 8 | |
3b156801 | 9 | -export( |
4af0774b SK |
10 | [ return/1 |
11 | , map/2 | |
12 | , pipe/2 | |
8fc25ea1 | 13 | , lift_exn/1 |
b79afea0 | 14 | , lift_exn/2 |
3b156801 | 15 | ]). |
6731749b SK |
16 | |
17 | ||
3b156801 SK |
18 | -type t(A, B) :: |
19 | {ok, A} | |
20 | | {error, B} | |
21 | . | |
6731749b SK |
22 | |
23 | ||
4af0774b SK |
24 | -spec return(A) -> |
25 | {ok, A}. | |
26 | return(X) -> | |
27 | {ok, X}. | |
28 | ||
29 | -spec map(t(A, Error), fun((A) -> (B))) -> | |
30 | t(B, Error). | |
31 | map({ok, X}, F) -> | |
32 | {ok, F(X)}; | |
33 | map({error, _}=Error, _) -> | |
34 | Error. | |
35 | ||
ed9905af SK |
36 | -spec pipe([F], X) -> |
37 | t(Ok, Error) | |
38 | when X :: any() | |
39 | , Ok :: any() | |
40 | , Error :: any() | |
41 | , F :: fun((X) -> t(Ok, Error)) | |
42 | . | |
3efbdbc9 SK |
43 | pipe([], X) -> |
44 | {ok, X}; | |
6731749b SK |
45 | pipe([F|Fs], X) -> |
46 | case F(X) | |
47 | of {error, _}=E -> E | |
48 | ; {ok, Y} -> pipe(Fs, Y) | |
49 | end. | |
8fc25ea1 SK |
50 | |
51 | -spec lift_exn(F) -> G | |
52 | when F :: fun((A)-> B) | |
53 | , G :: fun((A)-> t(B, {Class, Reason :: any()})) | |
54 | , Class :: error | |
55 | | exit | |
56 | | throw | |
57 | . | |
58 | lift_exn(F) when is_function(F, 1) -> | |
59 | fun(X) -> | |
60 | try | |
61 | {ok, F(X)} | |
62 | catch Class:Reason -> | |
63 | {error, {Class, Reason}} | |
64 | end | |
65 | end. | |
b79afea0 SK |
66 | |
67 | -spec lift_exn(F, Label) -> G | |
68 | when F :: fun((A)-> B) | |
69 | , G :: fun((A)-> t(B, {Label, {Class, Reason :: any()}})) | |
70 | , Class :: error | |
71 | | exit | |
72 | | throw | |
73 | . | |
74 | lift_exn(F, Label) when is_function(F, 1) -> | |
75 | fun(X) -> | |
76 | try | |
77 | {ok, F(X)} | |
78 | catch Class:Reason -> | |
79 | {error, {Label, {Class, Reason}}} | |
80 | end | |
81 | end. |