logos calculator example

src/ast/mod.rs

@@ -0,0 +1,12 @@
+pub mod evaluator;
+
+#[derive(Debug)]
+pub enum Expression {
+    Integer(isize),
+    Negate(Box<Expression>),
+    // Binary operators,
+    Add(Box<Expression>, Box<Expression>),
+    Substract(Box<Expression>, Box<Expression>),
+    Multiply(Box<Expression>, Box<Expression>),
+    Divide(Box<Expression>, Box<Expression>),
+}