From 971ab9ba21f2e2e9d1113b06e7b59c990657927a Mon Sep 17 00:00:00 2001
From: greg <greg.shuflin@protonmail.com>
Date: Wed, 30 Dec 2015 21:14:23 -0800
Subject: [PATCH] Implement paren expressions

---
 src/parser.rs | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/parser.rs b/src/parser.rs
index d0f7ec4..7527126 100644
--- a/src/parser.rs
+++ b/src/parser.rs
@@ -145,8 +145,20 @@ impl Parser {
     }
 
     fn factor(&mut self) -> ParseResult<AST> {
-        let n = try!(self.expect_num_literal());
-        Ok(AST::Number(n))
+        use tokenizer::Token::*;
+        match self.lookahead() {
+            Some(LParen) => {
+                self.next();
+                let expr = try!(self.expr());
+                try!(self.expect(RParen));
+                Ok(expr)
+            },
+            Some(NumLiteral(n)) => {
+                self.next();
+                Ok(AST::Number(n))
+            },
+            _ => Err(ParseError { err: format!("Expected LParen or NumLiteral") })
+        }
     }
 }