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|
//! Auxiliary macros.
/// Create trait implementations for an error type.
macro_rules! error_type {
(
$this:ident: $type:ident,
$(res: $res:ident,)*
show: $f:ident => $show:expr,
$(source: $source:expr,)*
$(from: ($err:ident: $from:path, $conv:expr),)*
) => {
// Possibly create a result type.
$(type $res<T> = std::result::Result<T, $type>;)*
impl std::fmt::Display for $type {
fn fmt(&$this, $f: &mut std::fmt::Formatter) -> std::fmt::Result {
$show
}
}
debug_display!($type);
impl std::error::Error for $type {
// The source method is only generated if an implementation was given.
$(fn source(&$this) -> Option<&(dyn std::error::Error + 'static)> {
$source
})*
}
// Create any number of from implementations.
$(impl From<$from> for $type {
fn from($err: $from) -> $type {
$conv
}
})*
};
}
/// Create a `Debug` implementation from a `Display` implementation.
macro_rules! debug_display {
($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 $name::*;
};
}
/// Whether an expression matches a set of patterns.
macro_rules! matches {
($expression:expr, $( $pattern:pat )|+ $( if $guard: expr )?) => {
match $expression {
$( $pattern )|+ $( if $guard )? => true,
_ => false
}
}
}
|
