From 619879b5bd86a99334affe1f05d17616cc2c1898 Mon Sep 17 00:00:00 2001
From: Jens Vollinga <jensv@nikhef.nl>
Date: Wed, 15 Jul 2009 05:19:07 +0200
Subject: [PATCH 1/1] Allow underscores in identifiers.

---
 ginac/parser/lexer.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/ginac/parser/lexer.cpp b/ginac/parser/lexer.cpp
index 1cc2f496..cc3be3d9 100644
--- a/ginac/parser/lexer.cpp
+++ b/ginac/parser/lexer.cpp
@@ -43,12 +43,12 @@ int lexer::gettok()
 	// Skip any whitespace.
 	c = skipspace(input, c, line_num);
 
-	// identifier: [a-zA-Z][a-zA-Z0-9]*
+	// identifier: [a-zA-Z][a-zA-Z0-9_]*
 	if (isalpha(c)) { 
 		str = c;
 		do {
 			c = input->get();
-			if (isalnum(c))
+			if ( isalnum(c) || c=='_' )
 				str += c;
 			else
 				break;
-- 
2.44.0