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nac3/nac3parser/src/mode.rs

41 lines
921 B
Rust

use crate::token::Tok;
#[derive(Clone, Copy)]
pub enum Mode {
Module,
Interactive,
Expression,
}
impl Mode {
pub(crate) fn to_marker(self) -> Tok {
match self {
Self::Module => Tok::StartModule,
Self::Interactive => Tok::StartInteractive,
Self::Expression => Tok::StartExpression,
}
}
}
impl std::str::FromStr for Mode {
type Err = ModeParseError;
fn from_str(s: &str) -> Result<Self, ModeParseError> {
match s {
"exec" | "single" => Ok(Mode::Module),
"eval" => Ok(Mode::Expression),
_ => Err(ModeParseError { _priv: () }),
}
}
}
#[derive(Debug)]
pub struct ModeParseError {
_priv: (),
}
impl std::fmt::Display for ModeParseError {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
write!(f, r#"mode should be "exec", "eval", or "single""#)
}
}