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Diffstat (limited to 'nitrocli/src/arg_util.rs')
-rw-r--r-- | nitrocli/src/arg_util.rs | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/nitrocli/src/arg_util.rs b/nitrocli/src/arg_util.rs new file mode 100644 index 0000000..6dd14ed --- /dev/null +++ b/nitrocli/src/arg_util.rs @@ -0,0 +1,79 @@ +// arg_util.rs + +// ************************************************************************* +// * Copyright (C) 2019 Daniel Mueller (deso@posteo.net) * +// * * +// * This program is free software: you can redistribute it and/or modify * +// * it under the terms of the GNU General Public License as published by * +// * the Free Software Foundation, either version 3 of the License, or * +// * (at your option) any later version. * +// * * +// * This program is distributed in the hope that it will be useful, * +// * but WITHOUT ANY WARRANTY; without even the implied warranty of * +// * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * +// * GNU General Public License for more details. * +// * * +// * You should have received a copy of the GNU General Public License * +// * along with this program. If not, see <http://www.gnu.org/licenses/>. * +// ************************************************************************* + +/// A macro for generating an enum with a set of simple (i.e., no +/// parameters) variants and their textual representations. +// TODO: Right now we hard code the derives we create. We may want to +// make this set configurable. +macro_rules! Enum { + ( $name:ident, [ $( $var:ident => $str:expr ), *] ) => { + #[derive(Clone, Copy, Debug, PartialEq)] + #[allow(unused)] + pub enum $name { + $( + $var, + )* + } + + impl AsRef<str> for $name { + fn as_ref(&self) -> &'static str { + match *self { + $( + $name::$var => $str, + )* + } + } + } + + impl ::std::fmt::Display for $name { + fn fmt(&self, f: &mut ::std::fmt::Formatter<'_>) -> ::std::fmt::Result { + write!(f, "{}", self.as_ref()) + } + } + + impl ::std::str::FromStr for $name { + type Err = (); + + fn from_str(s: &str) -> ::std::result::Result<Self, Self::Err> { + match s { + $( + $str => Ok($name::$var), + )* + _ => Err(()), + } + } + } + } +} + +#[cfg(test)] +mod tests { + Enum! {Command, [ + Var1 => "var1", + Var2 => "2", + Var3 => "crazy" + ]} + + #[test] + fn text_representations() { + assert_eq!(Command::Var1.as_ref(), "var1"); + assert_eq!(Command::Var2.as_ref(), "2"); + assert_eq!(Command::Var3.as_ref(), "crazy"); + } +} |