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use std::fmt;
use crate::{ParseError, err::{perr, ParseErrorKind::*}};
/// A bool literal: `true` or `false`. Also see [the reference][ref].
///
/// Notice that, strictly speaking, from Rust point of view "boolean literals" are not
/// actual literals but [keywords].
///
/// [ref]: https://doc.rust-lang.org/reference/expressions/literal-expr.html#boolean-literal-expressions
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum BoolLit {
False,
True,
}
impl BoolLit {
/// Parses the input as a bool literal. Returns an error if the input is
/// invalid or represents a different kind of literal.
pub fn parse(s: &str) -> Result<Self, ParseError> {
match s {
"false" => Ok(Self::False),
"true" => Ok(Self::True),
_ => Err(perr(None, InvalidLiteral)),
}
}
/// Returns the actual Boolean value of this literal.
pub fn value(self) -> bool {
match self {
Self::False => false,
Self::True => true,
}
}
/// Returns the literal as string.
pub fn as_str(&self) -> &'static str {
match self {
Self::False => "false",
Self::True => "true",
}
}
}
impl fmt::Display for BoolLit {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.pad(self.as_str())
}
}
#[cfg(test)]
mod tests;