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: 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: T) => 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: char) => 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: usize) => 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: ArgAction) => 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: ValueHint) => 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: ValueParser) => 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: &str) => 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: &str) => 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: &str) => 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 | } |
213 | |