51 lines
1.4 KiB
Rust
51 lines
1.4 KiB
Rust
/// Create an error type.
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macro_rules! error_type {
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(
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$var:ident: $err:ident,
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$(res: $res:ident,)*
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show: $f:ident => $show:expr,
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$(source: $source:expr,)*
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$(from: ($from:path, $conv:expr),)*
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) => {
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// Possibly create a result type.
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$(type $res<T> = std::result::Result<T, $err>;)*
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impl std::fmt::Display for $err {
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fn fmt(&self, $f: &mut std::fmt::Formatter) -> std::fmt::Result {
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#[allow(unused)]
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let $var = self;
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$show
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}
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}
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debug_display!($err);
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impl std::error::Error for $err {
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// The source method is only generated if an implementation was given.
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$(fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
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#[allow(unused)]
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let $var = self;
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$source
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})*
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}
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// Create any number of from implementations.
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$(impl From<$from> for $err {
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fn from($var: $from) -> $err {
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$conv
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}
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})*
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};
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}
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/// Create a `Debug` implementation from a display implementation.
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macro_rules! debug_display {
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($type:ident) => {
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impl std::fmt::Debug for $type {
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fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
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std::fmt::Display::fmt(self, f)
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}
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}
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};
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}
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