1 files changed, 70 insertions, 0 deletions

diff --git a/src/lisp/number.rs b/src/lisp/number.rs
new file mode 100644
index 0000000..ddadbe6
--- /dev/null
+++ b/src/lisp/number.rs
@@ -0,0 +1,70 @@
+use std::{
+    fmt::*,
+    ops::{Add, Div, Mul, Sub},
+};
+
+#[derive(Debug, Copy, Clone)]
+pub enum LispNumber {
+    Integer(i64),
+    Float(f64),
+}
+
+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 Display for LispNumber {
+    fn fmt(&self, f: &mut Formatter<'_>) -> Result {
+        match self {
+            LispNumber::Integer(v) => write!(f, "{}", v),
+            LispNumber::Float(v) => write!(f, "{}", v),
+        }
+    }
+}