diff --git a/src/grammar.rs b/src/grammar.rs
index 7eb1ac8..bf63666 100644
--- a/src/grammar.rs
+++ b/src/grammar.rs
@@ -1,5 +1,5 @@
 
-#[derive(Show)]
+#[derive(Debug)]
 #[derive(Clone)]
 #[derive(PartialEq)]
 pub enum AddOp {
@@ -7,7 +7,7 @@ pub enum AddOp {
   Subtract,
 }
 
-#[derive(Show)]
+#[derive(Debug)]
 #[derive(Clone)]
 #[derive(PartialEq)]
 pub enum MultOp {
@@ -17,16 +17,16 @@ pub enum MultOp {
 }
 
 #[derive(Clone)]
-#[derive(Show)]
+#[derive(Debug)]
 #[derive(PartialEq)]
 pub struct AddTerm(pub AddOp, pub Expr);
 
 #[derive(Clone)]
-#[derive(Show)]
+#[derive(Debug)]
 #[derive(PartialEq)]
 pub struct MultTerm(pub MultOp, pub Expr);
 
-#[derive(Show)]
+#[derive(Debug)]
 #[derive(Clone)]
 #[derive(PartialEq)]
 pub enum Expr {
@@ -38,12 +38,12 @@ pub enum Expr {
 
 
 //for now this is it's own type and not a statement
-#[derive(Show)]
+#[derive(Debug)]
 #[derive(Clone)]
 #[derive(PartialEq)]
 pub struct Block(pub Vec<Statement>);
 
-#[derive(Show)]
+#[derive(Debug)]
 #[derive(Clone)]
 #[derive(PartialEq)]
 pub enum Statement {
@@ -53,7 +53,7 @@ pub enum Statement {
   While(Expr, Comparator, Expr, Block),
 }
 
-#[derive(Show)]
+#[derive(Debug)]
 #[derive(Clone)]
 #[derive(Eq)]
 #[derive(PartialEq)]
@@ -68,7 +68,7 @@ pub enum Comparator {
 
 
 
-#[derive(Show)]
+#[derive(Debug)]
 #[derive(Eq)]
 #[derive(PartialEq)]
 #[derive(Clone)]
diff --git a/src/lexer.rs b/src/lexer.rs
index 80a1369..e186f4a 100644
--- a/src/lexer.rs
+++ b/src/lexer.rs
@@ -11,10 +11,10 @@ use std::str::FromStr;
 pub fn token() -> Box<SliceParser<I=str, O=Vec<Token>>> {
 
   fn lt(s: &str, t: Token) -> RegexLiteralParser<Token> {
-    str_lit((String::from_str(r"^[ \t]*") + s).as_str(), t)
+    str_lit((String::from_str(r"^[ \t]*").unwrap() + s).as_str(), t)
   }
 
-  let ident = capture(r"^[ \t]*([a-zA-Z]\w*)[ \t]*", |caps| Token::Ident(String::from_str(caps.at(1).unwrap()))); 
+  let ident = capture(r"^[ \t]*([a-zA-Z]\w*)[ \t]*", |caps| Token::Ident(String::from_str(caps.at(1).unwrap()).unwrap()));
 
   let number = capture(r"^[ \t]*(\d+)[ \t]*", |caps| Token::Number(FromStr::from_str(caps.at(1).unwrap()).unwrap()));
 
diff --git a/src/main.rs b/src/main.rs
index 67caf2f..26cb820 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,4 @@
+#![feature(custom_derive)]
 #![feature(unboxed_closures)]
 #![feature(collections)]
 #![feature(convert)]