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//! This contains error and result types that can happen while parsing
//! Derivations from ATerm.
use nom::IResult;
use crate::nixhash;
pub type NomResult<I, O> = IResult<I, O, NomError<I>>;
#[derive(Debug, PartialEq)]
pub enum ErrorKind {
// duplicate key in map
DuplicateMapKey(String),
// Digest parsing error
NixHashError(nixhash::Error),
// error kind wrapped from native nom errors
Nom(nom::error::ErrorKind),
}
/// Our own error type to pass along parser-related errors.
#[derive(Debug, PartialEq)]
pub struct NomError<I> {
/// position of the error in the input data
pub input: I,
/// error code
pub code: ErrorKind,
}
impl<I, E> nom::error::FromExternalError<I, E> for NomError<I> {
fn from_external_error(input: I, kind: nom::error::ErrorKind, _e: E) -> Self {
Self {
input,
code: ErrorKind::Nom(kind),
}
}
}
impl<I> nom::error::ParseError<I> for NomError<I> {
fn from_error_kind(input: I, kind: nom::error::ErrorKind) -> Self {
Self {
input,
code: ErrorKind::Nom(kind),
}
}
// FUTUREWORK: implement, so we have support for backtracking through the
// parse tree?
fn append(_input: I, _kind: nom::error::ErrorKind, other: Self) -> Self {
other
}
}
/// This wraps a [nom::error::Error] into our error.
impl<I> From<nom::error::Error<I>> for NomError<I> {
fn from(value: nom::error::Error<I>) -> Self {
Self {
input: value.input,
code: ErrorKind::Nom(value.code),
}
}
}
/// This essentially implements
/// From<nom::Err<nom::error::Error<I>>> for nom::Err<NomError<I>>,
/// which we can't because nom::Err<_> is a foreign type.
pub(crate) fn into_nomerror<I>(e: nom::Err<nom::error::Error<I>>) -> nom::Err<NomError<I>> {
match e {
nom::Err::Incomplete(n) => nom::Err::Incomplete(n),
nom::Err::Error(e) => nom::Err::Error(e.into()),
nom::Err::Failure(e) => nom::Err::Failure(e.into()),
}
}
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