1.1 --- a/lemon/lemon_writer.h	Tue Dec 06 18:44:26 2005 +0000
     1.2 +++ b/lemon/lemon_writer.h	Wed Dec 07 11:57:30 2005 +0000
     1.3 @@ -172,7 +172,7 @@
     1.4  
     1.5        virtual ~MapWriterBase() {}
     1.6  
     1.7 -      virtual void write(std::ostream& os, const Item& item) = 0;
     1.8 +      virtual void write(std::ostream& os, const Item& item) const = 0;
     1.9      };
    1.10  
    1.11  
    1.12 @@ -192,7 +192,7 @@
    1.13  
    1.14        virtual ~MapWriter() {}
    1.15  
    1.16 -      virtual void write(std::ostream& os, const Item& item) {
    1.17 +      virtual void write(std::ostream& os, const Item& item) const {
    1.18  	Value value = map[item];
    1.19  	writer.write(os, value);
    1.20        }