From 17ae669b30cb01d0404ced06b8e04525392fea0e Mon Sep 17 00:00:00 2001
From: Yuichi Nishiwaki <yuichi.nishiwaki@gmail.com>
Date: Tue, 18 Feb 2014 17:24:08 +0900
Subject: [PATCH] support nested comments

---
 src/scan.l | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/scan.l b/src/scan.l
index 7e0a64e3..90a62c51 100644
--- a/src/scan.l
+++ b/src/scan.l
@@ -57,11 +57,31 @@ infnan		"+inf.0"|"-inf.0"|"+nan.0"|"-nan.0"
   /* bytevector */
 %x BYTEVECTOR
 
+  /* block comment */
+%x BLOCK_COMMENT
+
 %%
 
 [ \t\n\r]	/* skip whitespace */
 {comment}	/* skip comment */
 
+"#|"		{
+  BEGIN(BLOCK_COMMENT);
+  yylvalp->i = 0;
+}
+<BLOCK_COMMENT>"#|" 	{
+  yylvalp->i++;
+}
+<BLOCK_COMMENT>"|#"	{
+  if (yylvalp->i == 0)
+    BEGIN(INITIAL);
+  else
+    yylvalp->i--;
+}
+<BLOCK_COMMENT>.	{
+  yymore();
+}
+
 "#;"		return tDATUM_COMMENT;
 "."		return tDOT;
 "("		return tLPAREN;