Hi, Many applications are required to parse a string/file and extract numeric values. You can use sscanf or alternatively use regexp with numeric casting templates. I suprised that boost doesn't seem to contain conversion templates like: template < typename t_target > t_target decimal_cast( const std::string& arg ){ ... }; template < typename t_target > t_target octal_cast( const std::string& arg ){ ... }; template < typename t_target > t_target hex_cast( const std::string& arg ){ ... }; When you use these type of casts with regexp, you can construct simple robust parsers for reading numeric data from files, etc ..., in just a few lines of code. The lexical_cast and numeric_cast don't seem to cover these conversions. This is much better approach than using parsing framework like spirit/antlr. Shouldn't boost have this capability. Regards