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25 lines
662 B
Rust
25 lines
662 B
Rust
macro_rules! enum_number {
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($name:ident { $($variant:ident = $value:expr, )* }) => {
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enum $name {
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$($variant = $value,)*
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}
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fn foo(value: i32) -> Option<$name> {
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match value {
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$( $value => Some($name::$variant), )* // PatKind::Lit
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$( $value ..= 42 => Some($name::$variant), )* // PatKind::Range
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_ => None
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}
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}
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}
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}
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enum_number!(Change {
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Pos = 1,
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Neg = -1,
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Arith = 1 + 1, //~ ERROR arbitrary expressions aren't allowed in patterns
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//~| ERROR arbitrary expressions aren't allowed in patterns
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});
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fn main() {}
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