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use super::*;
use std::fmt::{Display, Formatter, Result};

/// The error of parser handling.
///
/// Not recommended to use it at other times.
#[derive(Debug)]
pub enum PError {
    /// If parser mismatched, just choose another one.
    Mismatch,
    /// The parser is the only one can be matched.
    Terminate(u64, String),
}

impl PError {
    /// Transform to IO error.
    pub fn into_error(self, doc: &str) -> String {
        match self {
            Self::Mismatch => String::from("not matched"),
            Self::Terminate(pos, name) => {
                format!("invalid {}: \n\n{}", name, indicated_msg(doc, pos))
            }
        }
    }
}

impl From<()> for PError {
    fn from(_: ()) -> Self {
        Self::Mismatch
    }
}

impl Display for PError {
    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
        f.write_fmt(format_args!("{:?}", self))
    }
}