rename env to eval, add div operator

1 files changed, 21 insertions, 3 deletions

diff --git a/src/lisp/number.rs b/src/lisp/number.rs
index ddadbe6..18a41f7 100644
--- a/src/lisp/number.rs
+++ b/src/lisp/number.rs
@@ -1,14 +1,32 @@
 use std::{
-    fmt::*,
+    fmt,
     ops::{Add, Div, Mul, Sub},
 };
 
+use crate::lisp::error::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.) {
+            return Err(LispError::EvalError);
+        } else {
+            return 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),
+            });
+        }
+    }
+}
+
 impl Add for LispNumber {
     type Output = Self;
     fn add(self, rhs: Self) -> Self::Output {
@@ -60,8 +78,8 @@ impl PartialEq for LispNumber {
     }
 }
 
-impl Display for LispNumber {
-    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+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),