Report sytax errors

src/repl/mod.rs

@@ -1,6 +1,7 @@
 use std::io::{self, Write};
 
 use crate::symbol_table::SymbolTable;
+use crate::token::Token;
 
 use super::lexic;
 use super::syntax;
@@ -12,11 +13,7 @@ fn compile(input: &String) {
 
     match _tokens {
         Ok(tokens) => {
-            let mut ast = syntax::construct_ast(&tokens).unwrap();
+            build_ast(tokens);
-            let mut table = SymbolTable::new();
-            semantic::check_ast(&mut ast, &mut table);
-            let js_code = codegen::codegen(&ast);
-            println!("{}", js_code)
         },
         Err(error) => {
             eprintln!("Error scanning.\n{} at pos {}", error.reason, error.position)
@@ -25,6 +22,22 @@ fn compile(input: &String) {
 
 }
 
+fn build_ast(tokens: Vec<Token>) {
+    let ast = syntax::construct_ast(&tokens);
+
+    match ast {
+        Ok(mut ast) => {
+            let mut table = SymbolTable::new();
+            semantic::check_ast(&mut ast, &mut table);
+            let js_code = codegen::codegen(&ast);
+            println!("{}", js_code)
+        }
+        Err(reason) => {
+            eprintln!("Syntax error.\n{}", reason)
+        }
+    }
+}
+
 pub fn run() -> io::Result<()> {
     let stdin = io::stdin();
     let mut buffer = String::new();

src/token.rs

@@ -1,7 +1,6 @@
 #[derive(PartialEq, Debug, Clone)]
 pub enum TokenType {
     Identifier,
-    Comment,
     Number,
     String,
     Operator,