vendor/clap_builder-4.3.10/src/builder/resettable.rs

   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 }