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use std::result;
use std::convert::From;
use std::error::Error as StdError;
use std::fmt;
use regex;
pub type Result<T> = result::Result<T, Error>;
#[derive(Debug)]
pub enum Error {
Syntax(String),
UndefVariable(String),
Backref(String),
DuplicateDef(String),
Regex(regex::Error),
}
impl StdError for Error {
fn description(&self) -> &str {
use Error::*;
match *self {
Syntax(ref s) |
UndefVariable(ref s) |
Backref(ref s) |
DuplicateDef(ref s) => s,
Regex(ref err) => err.description(),
}
}
fn cause(&self) -> Option<&StdError> {
use Error::*;
match *self {
Regex(ref err) => Some(err),
_ => None,
}
}
}
impl fmt::Display for Error {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
write!(fmt, "{}", self.description())
}
}
impl From<regex::Error> for Error {
fn from(e: regex::Error) -> Error {
Error::Regex(e)
}
}