From 3e0c60f1dcf3d333cbcb2a9c6e0ca1c0a74d2d8c Mon Sep 17 00:00:00 2001
From: Anicka Bernathova <anicka@anicka.net>
Date: Thu, 3 Jul 2008 13:16:30 +0200
Subject: [PATCH] do not unget EOF

---
 cond.y | 31 ++++++++++++++++++++-----------
 1 file changed, 20 insertions(+), 11 deletions(-)

diff --git a/cond.y b/cond.y
index 1dc42c3..cb995c6 100644
--- a/cond.y
+++ b/cond.y
@@ -109,6 +109,16 @@ get_string_out(char delim)
 	return s;
 }
 
+int
+safe_unget(char c)
+{
+	if (c==EOF)
+		return 0;
+
+	ungetc(c,stdin);
+	return 1;
+}
+
 int
 yylex(void)
 {
@@ -147,39 +157,38 @@ yylex(void)
 		else if (c == '~')
 			return NRE;
 		else
-			ungetc(c,stdin);
+			if (! safe_unget(c))
+				return c;
 	}
 
 	if (c == '<'){
 		if ((c = getchar ()) == '=')
 			return LE;
-		else {
-			ungetc(c,stdin);
-			return LT;
-		}
+		else
+			return (safe_unget(c) ? LT : c); 
 	}
 
 	if (c == '>'){
 		if ((c = getchar ()) == '=')
 			return GE;
-		else {
-			ungetc(c,stdin);
-			return GT;
-		}
+		else
+			return (safe_unget(c) ? GT : c); 
 	}
 
 	if (c == '='){
 		if ((c = getchar ()) == '=')
 			return EQ;
 		else
-			ungetc(c,stdin);
+			if (! safe_unget(c))
+				return c;
 	}
 
 	if (c == '~'){
 		if ((c = getchar ()) == '~')
 			return RE;
 		else
-			ungetc(c,stdin);
+			if (! safe_unget(c))
+				return c;
 	}
 	
 	if (c == EOF)
-- 
2.39.2