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//! Auxiliary macros.
/// Create trait implementations for an error type.
macro_rules! error_type {
(
$var:ident: $err:ident,
$(res: $res:ident,)*
show: $f:ident => $show:expr,
$(source: $source:expr,)*
$(from: ($from:path, $conv:expr),)*
) => {
// Possibly create a result type.
$(type $res<T> = std::result::Result<T, $err>;)*
impl std::fmt::Display for $err {
fn fmt(&self, $f: &mut std::fmt::Formatter) -> std::fmt::Result {
#[allow(unused)]
let $var = self;
$show
}
}
debug_display!($err);
impl std::error::Error for $err {
// The source method is only generated if an implementation was given.
$(fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
#[allow(unused)]
let $var = self;
$source
})*
}
// Create any number of from implementations.
$(impl From<$from> for $err {
fn from($var: $from) -> $err {
$conv
}
})*
};
}
/// Shorthand for checking whether an expression matches a pattern.
macro_rules! matches {
($expr:expr, $($pattern:tt)*) => {
match $expr {
$($pattern)* => true,
_ => false,
}
};
}
/// Create a `Debug` implementation from a `Display` implementation.
macro_rules! debug_display {
($type:ident) => (
impl std::fmt::Debug for $type {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
std::fmt::Display::fmt(self, f)
}
}
);
($type:ident; $generics:tt where $($bounds:tt)*) => (
impl<$generics> std::fmt::Debug for $type<$generics> where $($bounds)* {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
std::fmt::Display::fmt(self, f)
}
}
);
}
/// Declare a module and reexport all its contents.
macro_rules! pub_use_mod {
($name:ident) => {
mod $name;
pub use $name::*;
};
}
|
