From e80c05bb4840af91a14583438d0b6b1296bdc799 Mon Sep 17 00:00:00 2001
From: Andrew Johnson <andrewjohnson@Andrews-MacBook-Pro.local>
Date: Fri, 25 May 2018 13:52:06 -0600
Subject: [PATCH] kleene start

---
 Chapter09/metaprogramming_ebnf.rs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Chapter09/metaprogramming_ebnf.rs b/Chapter09/metaprogramming_ebnf.rs
index 49e38c6..b08bc04 100644
--- a/Chapter09/metaprogramming_ebnf.rs
+++ b/Chapter09/metaprogramming_ebnf.rs
@@ -15,6 +15,12 @@ macro_rules! abc_or_aaa {
   (a a a) => { println!("'a a a' is also correct syntax.") };
 }
 
+//this is a grammar sequence matching many of one token
+macro_rules! many_a {
+  ( $($a:ident)* ) => {{ $( print!("one {} ", stringify!($a)); )* println!(""); }};
+  ( $($a:ident),* ) => {{ $( print!("one {} comma ", stringify!($a)); )* println!(""); }};
+}
+
 fn main() {
    abc!(a b c);
 
@@ -23,4 +29,7 @@ fn main() {
 
    abc_or_aaa!(a b c);
    abc_or_aaa!(a a a);
+
+   many_a!(a a a);
+   many_a!(a, a, a);
 }