parser in rust

rust/rox/src/expression.rs

@@ -0,0 +1,20 @@
+use crate::token::{self, Token};
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum Expression {
+    Binary {
+        left: Box<Expression>,
+        operator: Token,
+        right: Box<Expression>,
+    },
+    Grouping {
+        expression: Box<Expression>,
+    },
+    Literal {
+        value: token::Literal,
+    },
+    Unary {
+        operator: Token,
+        right: Box<Expression>,
+    },
+}