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add651ee FG |
1 | // Unlike `impl Into<Option<T>>` or `Option<impl Into<T>>`, this isn't ambiguous for the `None` |
2 | // case. | |
3 | ||
4 | use crate::builder::ArgAction; | |
5 | use crate::builder::OsStr; | |
6 | use crate::builder::Str; | |
7 | use crate::builder::StyledStr; | |
8 | use crate::builder::ValueHint; | |
9 | use crate::builder::ValueParser; | |
10 | use crate::builder::ValueRange; | |
11 | ||
12 | /// Clearable builder value | |
13 | /// | |
14 | /// This allows a builder function to both accept any value that can [`Into::into`] `T` (like | |
15 | /// `&str` into `OsStr`) as well as `None` to reset it to the default. This is needed to | |
16 | /// workaround a limitation where you can't have a function argument that is `impl Into<Option<T>>` | |
17 | /// where `T` is `impl Into<S>` accept `None` as its type is ambiguous. | |
18 | /// | |
19 | /// # Example | |
20 | /// | |
21 | /// ```rust | |
22 | /// # use clap_builder as clap; | |
23 | /// # use clap::Command; | |
24 | /// # use clap::Arg; | |
25 | /// fn common() -> Command { | |
26 | /// Command::new("cli") | |
27 | /// .arg(Arg::new("input").short('i').long("input")) | |
28 | /// } | |
29 | /// let mut command = common(); | |
30 | /// command.mut_arg("input", |arg| arg.short(None)); | |
31 | /// ``` | |
32 | #[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash)] | |
33 | pub enum Resettable<T> { | |
34 | /// Overwrite builder value | |
35 | Value(T), | |
36 | /// Reset builder value | |
37 | Reset, | |
38 | } | |
39 | ||
40 | impl<T> Resettable<T> { | |
41 | pub(crate) fn into_option(self) -> Option<T> { | |
42 | match self { | |
43 | Self::Value(t) => Some(t), | |
44 | Self::Reset => None, | |
45 | } | |
46 | } | |
47 | } | |
48 | ||
49 | impl<T> From<T> for Resettable<T> { | |
50 | fn from(other: T) -> Self { | |
51 | Self::Value(other) | |
52 | } | |
53 | } | |
54 | ||
55 | impl<T> From<Option<T>> for Resettable<T> { | |
56 | fn from(other: Option<T>) -> Self { | |
57 | match other { | |
58 | Some(inner) => Self::Value(inner), | |
59 | None => Self::Reset, | |
60 | } | |
61 | } | |
62 | } | |
63 | ||
64 | /// Convert to the intended resettable type | |
65 | pub trait IntoResettable<T> { | |
66 | /// Convert to the intended resettable type | |
67 | fn into_resettable(self) -> Resettable<T>; | |
68 | } | |
69 | ||
70 | impl IntoResettable<char> for Option<char> { | |
71 | fn into_resettable(self) -> Resettable<char> { | |
72 | match self { | |
73 | Some(s) => Resettable::Value(s), | |
74 | None => Resettable::Reset, | |
75 | } | |
76 | } | |
77 | } | |
78 | ||
79 | impl IntoResettable<usize> for Option<usize> { | |
80 | fn into_resettable(self) -> Resettable<usize> { | |
81 | match self { | |
82 | Some(s) => Resettable::Value(s), | |
83 | None => Resettable::Reset, | |
84 | } | |
85 | } | |
86 | } | |
87 | ||
88 | impl IntoResettable<ArgAction> for Option<ArgAction> { | |
89 | fn into_resettable(self) -> Resettable<ArgAction> { | |
90 | match self { | |
91 | Some(s) => Resettable::Value(s), | |
92 | None => Resettable::Reset, | |
93 | } | |
94 | } | |
95 | } | |
96 | ||
97 | impl IntoResettable<ValueHint> for Option<ValueHint> { | |
98 | fn into_resettable(self) -> Resettable<ValueHint> { | |
99 | match self { | |
100 | Some(s) => Resettable::Value(s), | |
101 | None => Resettable::Reset, | |
102 | } | |
103 | } | |
104 | } | |
105 | ||
106 | impl IntoResettable<ValueParser> for Option<ValueParser> { | |
107 | fn into_resettable(self) -> Resettable<ValueParser> { | |
108 | match self { | |
109 | Some(s) => Resettable::Value(s), | |
110 | None => Resettable::Reset, | |
111 | } | |
112 | } | |
113 | } | |
114 | ||
115 | impl IntoResettable<StyledStr> for Option<&'static str> { | |
116 | fn into_resettable(self) -> Resettable<StyledStr> { | |
117 | match self { | |
118 | Some(s) => Resettable::Value(s.into()), | |
119 | None => Resettable::Reset, | |
120 | } | |
121 | } | |
122 | } | |
123 | ||
124 | impl IntoResettable<OsStr> for Option<&'static str> { | |
125 | fn into_resettable(self) -> Resettable<OsStr> { | |
126 | match self { | |
127 | Some(s) => Resettable::Value(s.into()), | |
128 | None => Resettable::Reset, | |
129 | } | |
130 | } | |
131 | } | |
132 | ||
133 | impl IntoResettable<Str> for Option<&'static str> { | |
134 | fn into_resettable(self) -> Resettable<Str> { | |
135 | match self { | |
136 | Some(s) => Resettable::Value(s.into()), | |
137 | None => Resettable::Reset, | |
138 | } | |
139 | } | |
140 | } | |
141 | ||
142 | impl<T> IntoResettable<T> for Resettable<T> { | |
143 | fn into_resettable(self) -> Resettable<T> { | |
144 | self | |
145 | } | |
146 | } | |
147 | ||
148 | impl IntoResettable<char> for char { | |
149 | fn into_resettable(self) -> Resettable<char> { | |
150 | Resettable::Value(self) | |
151 | } | |
152 | } | |
153 | ||
154 | impl IntoResettable<usize> for usize { | |
155 | fn into_resettable(self) -> Resettable<usize> { | |
156 | Resettable::Value(self) | |
157 | } | |
158 | } | |
159 | ||
160 | impl IntoResettable<ArgAction> for ArgAction { | |
161 | fn into_resettable(self) -> Resettable<ArgAction> { | |
162 | Resettable::Value(self) | |
163 | } | |
164 | } | |
165 | ||
166 | impl IntoResettable<ValueHint> for ValueHint { | |
167 | fn into_resettable(self) -> Resettable<ValueHint> { | |
168 | Resettable::Value(self) | |
169 | } | |
170 | } | |
171 | ||
172 | impl<I: Into<ValueRange>> IntoResettable<ValueRange> for I { | |
173 | fn into_resettable(self) -> Resettable<ValueRange> { | |
174 | Resettable::Value(self.into()) | |
175 | } | |
176 | } | |
177 | ||
178 | impl<I: Into<ValueParser>> IntoResettable<ValueParser> for I { | |
179 | fn into_resettable(self) -> Resettable<ValueParser> { | |
180 | Resettable::Value(self.into()) | |
181 | } | |
182 | } | |
183 | ||
184 | impl<I: Into<String>> IntoResettable<String> for I { | |
185 | fn into_resettable(self) -> Resettable<String> { | |
186 | Resettable::Value(self.into()) | |
187 | } | |
188 | } | |
189 | ||
190 | impl<I: Into<StyledStr>> IntoResettable<StyledStr> for I { | |
191 | fn into_resettable(self) -> Resettable<StyledStr> { | |
192 | Resettable::Value(self.into()) | |
193 | } | |
194 | } | |
195 | ||
196 | impl<I: Into<OsStr>> IntoResettable<OsStr> for I { | |
197 | fn into_resettable(self) -> Resettable<OsStr> { | |
198 | Resettable::Value(self.into()) | |
199 | } | |
200 | } | |
201 | ||
202 | impl<I: Into<Str>> IntoResettable<Str> for I { | |
203 | fn into_resettable(self) -> Resettable<Str> { | |
204 | Resettable::Value(self.into()) | |
205 | } | |
206 | } | |
207 | ||
208 | impl<I: Into<crate::Id>> IntoResettable<crate::Id> for I { | |
209 | fn into_resettable(self) -> Resettable<crate::Id> { | |
210 | Resettable::Value(self.into()) | |
211 | } | |
212 | } |