querydown 0.0.1

An expressive DSL for writing relational database queries that compile to SQL
Documentation 
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use std::error;
use std::fmt;

#[derive(Clone, Debug)]
pub struct Error {
    kind: ErrorKind,
}

impl Error {
    pub(crate) fn new(kind: ErrorKind) -> Error {
        Error { kind }
    }

    pub(crate) fn unknown() -> Error {
        Error::new(ErrorKind::Unknown)
    }

    /// Return the kind of this error.
    pub fn kind(&self) -> &ErrorKind {
        &self.kind
    }
}

/// The kind of an error that can occur.
#[derive(Clone, Debug)]
pub enum ErrorKind {
    /// TODO: eliminate this variant in favor of more specific variants
    Unknown,
    /// Hints that destructuring should not be exhaustive.
    ///
    /// This enum may grow additional variants, so this makes sure clients
    /// don't count on exhaustive matching. (Otherwise, adding a new variant
    /// could break existing code.)
    #[doc(hidden)]
    __Nonexhaustive,
}

impl error::Error for Error {
    fn description(&self) -> &str {
        match self.kind {
            ErrorKind::Unknown => "Unknown error.",
            ErrorKind::__Nonexhaustive => unreachable!(),
        }
    }
}

impl fmt::Display for Error {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self.kind {
            ErrorKind::Unknown => write!(f, "Unknown error."),
            ErrorKind::__Nonexhaustive => unreachable!(),
        }
    }
}