add evaluator

src/main.rs

@@ -5,6 +5,8 @@ mod lexer;
 use lexer::Lexer;
 mod parser;
 use parser::Parser;
+mod eval;
+use eval::Evaluator;
 
 fn main() -> std::io::Result<()> {
     let args = std::env::args().collect::<Vec<String>>();
@@ -29,7 +31,11 @@ fn main() -> std::io::Result<()> {
         let parsed = parser.parse();
         match parsed {
             parser::Expr::EOL => break,
-            _ => println!("{:?}", parsed)
+            _ => {
+                println!("AST:   {:?}", parsed);
+                let eval = Evaluator::new(parsed);
+                println!("Eval:  {:?}", eval.eval());
+            }
         }
     }