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//! Contains helpers for parsing-related errors.
/// Creates an error type intended for string parsing errors.
///
/// The resulting error type has two fields: `input` and `source`. The type of `input` is
/// [`InputString`](super::InputString), the type of `source` is specified as the second argument
/// to the macro.
///
/// The resulting type is public, conditionally implements [`std::error::Error`] and has a private
/// `new()` method for convenience.
///
/// # Parameters
///
/// * `name` - the name of the error type
/// * `source` - the type of the source type
/// * `subject` - English description of the type being parsed (e.g. "a bitcoin amount")
/// * `derive` - list of derives to add
#[macro_export]
macro_rules! parse_error_type {
($vis:vis $name:ident, $source:ty, $subject:expr $(, $derive:path)* $(,)?) => {
#[derive(Debug $(, $derive)*)]
$vis struct $name {
input: $crate::error::InputString,
source: $source,
}
impl $name {
/// Creates `Self`.
fn new<T: Into<$crate::error::InputString>>(input: T, source: $source) -> Self {
$name {
input: input.into(),
source,
}
}
}
impl core::fmt::Display for $name {
fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
$crate::error::write_err!(f, "{}", self.input.display_cannot_parse($subject); self.source)
}
}
#[cfg(feature = "std")]
impl std::error::Error for $name {
fn source(&self) -> Option<&(dyn std::error::Error + 'static)> { Some(&self.source) }
}
}
}