// $Id: scanner.h 17 2007-08-19 18:51:39Z tb $
#ifndef EXAMPLE_SCANNER_H
#define EXAMPLE_SCANNER_H
// Flex expects the signature of yylex to be defined in the macro YY_DECL, and
// the C++ parser expects it to be declared. We can factor both as follows.
#ifndef YY_DECL
#define YY_DECL \ example::Parser::token_type \ example::Scanner::lex( \ example::Parser::semantic_type* yylval, \ example::Parser::location_type* yylloc \ )
#endif
#ifndef __FLEX_LEXER_H
#define yyFlexLexer ExampleFlexLexer
#include "FlexLexer.h"
#undef yyFlexLexer
#endif
#include "parser.h"
namespace example {
/** Scanner is a derived class to add some extra function to the scanner
* class. Flex itself creates a class named yyFlexLexer, which is renamed using
* macros to ExampleFlexLexer. However we change the context of the generated
* yylex() function to be contained within the Scanner class. This is required
* because the yylex() defined in ExampleFlexLexer has no parameters. */
class Scanner : public ExampleFlexLexer
{
public:
/** Create a new scanner object. The streams arg_yyin and arg_yyout default
* to cin and cout, but that assignment is only made when initializing in
* yylex(). */
Scanner(std::istream* arg_yyin = 0,
std::ostream* arg_yyout = 0);
/** Required for virtual functions */
virtual ~Scanner();
/** This is the main lexing function. It is generated by flex according to
* the macro declaration YY_DECL above. The generated bison parser then
* calls this virtual function to fetch new tokens. */
virtual Parser::token_type lex(
Parser::semantic_type* yylval,
Parser::location_type* yylloc
);
/** Enable debug output (via arg_yyout) if compiled into the scanner. */
void set_debug(bool b);
};
} // namespace example
#endif // EXAMPLE_SCANNER_H
