fennec-parser 0.1.8

// Copyright 2022 Gregory Petrosyan <pgregory@pgregory.net>
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

use std::fmt::{Debug, Error, Formatter};

pub enum Expr {
    Number(i32),
    Op(Box<Expr>, Opcode, Box<Expr>),
    Error,
}

#[derive(Copy, Clone)]
pub enum Opcode {
    Mul,
    Div,
    Add,
    Sub,
}

impl Debug for Expr {
    fn fmt(&self, fmt: &mut Formatter) -> Result<(), Error> {
        use self::Expr::{Error, Number, Op};
        match *self {
            Number(n) => write!(fmt, "{n:?}"),
            Op(ref l, op, ref r) => write!(fmt, "({l:?} {op:?} {r:?})"),
            Error => write!(fmt, "error"),
        }
    }
}

impl Debug for Opcode {
    fn fmt(&self, fmt: &mut Formatter) -> Result<(), Error> {
        use self::Opcode::{Add, Div, Mul, Sub};
        match *self {
            Mul => write!(fmt, "*"),
            Div => write!(fmt, "/"),
            Add => write!(fmt, "+"),
            Sub => write!(fmt, "-"),
        }
    }
}