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use std::{
cmp::{Eq, Ord, Ordering, PartialEq, PartialOrd},
convert::From,
fmt,
ops::{Add, Mul, Sub},
};
use crate::lisp::error::{EvalError, LispError};
#[derive(Debug, Copy, Clone)]
pub enum LispNumber {
Integer(i64),
Float(f64),
}
impl LispNumber {
pub fn div(self, rhs: Self) -> Result<LispNumber, LispError> {
use LispNumber::*;
if rhs == Integer(0) || rhs == Float(0.) {
Err(EvalError::DivByZero.into())
} else {
Ok(match (self, rhs) {
(Integer(a), Integer(b)) => Float(a as f64 / b as f64),
(Float(a), Integer(b)) => Float(a / b as f64),
(Integer(a), Float(b)) => Float(a as f64 / b),
(Float(a), Float(b)) => Float(a / b),
})
}
}
pub fn unwrap_integer(self) -> i64 {
match self {
Self::Integer(x) => x,
Self::Float(x) => x.floor() as i64, // lossy
}
}
}
impl Add for LispNumber {
type Output = Self;
fn add(self, rhs: Self) -> Self::Output {
use LispNumber::*;
match (self, rhs) {
(Integer(a), Integer(b)) => Integer(a + b),
(Float(a), Integer(b)) => Float(a + b as f64),
(Integer(a), Float(b)) => Float(a as f64 + b),
(Float(a), Float(b)) => Float(a + b),
}
}
}
impl Sub for LispNumber {
type Output = Self;
fn sub(self, rhs: Self) -> Self::Output {
use LispNumber::*;
match (self, rhs) {
(Integer(a), Integer(b)) => Integer(a - b),
(Float(a), Integer(b)) => Float(a - b as f64),
(Integer(a), Float(b)) => Float(a as f64 - b),
(Float(a), Float(b)) => Float(a - b),
}
}
}
impl Mul for LispNumber {
type Output = Self;
fn mul(self, rhs: Self) -> Self::Output {
use LispNumber::*;
match (self, rhs) {
(Integer(a), Integer(b)) => Integer(a * b),
(Float(a), Integer(b)) => Float(a * b as f64),
(Integer(a), Float(b)) => Float(a as f64 * b),
(Float(a), Float(b)) => Float(a * b),
}
}
}
impl PartialEq for LispNumber {
fn eq(&self, other: &Self) -> bool {
use LispNumber::*;
match (self, other) {
(Integer(a), Integer(b)) => *a == *b,
(Float(a), Integer(b)) => *a == *b as f64,
(Integer(a), Float(b)) => *a as f64 == *b,
(Float(a), Float(b)) => *a == *b,
}
}
}
impl Eq for LispNumber {}
impl Ord for LispNumber {
fn cmp(&self, other: &Self) -> Ordering {
use LispNumber::*;
match (*self, *other) {
(Integer(a), Integer(b)) => a.cmp(&b),
(Float(a), Integer(b)) => (a as i64).cmp(&b),
(Integer(a), Float(b)) => a.cmp(&(b as i64)),
(Float(a), Float(b)) => (a as i64).cmp(&(b as i64)),
}
}
}
impl PartialOrd for LispNumber {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl fmt::Display for LispNumber {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
LispNumber::Integer(v) => write!(f, "{}", v),
LispNumber::Float(v) => write!(f, "{}", v),
}
}
}
impl From<i64> for LispNumber {
fn from(target: i64) -> Self {
LispNumber::Integer(target)
}
}
|
