X-Git-Url: https://www.ginac.de/ginac.git//ginac.git?p=ginac.git;a=blobdiff_plain;f=ginac%2Fparser%2Flexer.cpp;h=cc3be3d91768c1f930b89bd71b12ca8a0672e410;hp=050c85f73454a865750932297b0d0885a1bb934f;hb=619879b5bd86a99334affe1f05d17616cc2c1898;hpb=1602530f716ba1d425a0667b897182b99c374823

diff --git a/ginac/parser/lexer.cpp b/ginac/parser/lexer.cpp
index 050c85f7..cc3be3d9 100644
--- a/ginac/parser/lexer.cpp
+++ b/ginac/parser/lexer.cpp
@@ -26,6 +26,7 @@
 #include <iostream>
 #include <sstream>
 #include <string>
+#include <cstdio>
 
 namespace GiNaC {
 
@@ -42,12 +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;