reader.hh

    
#ifndef already_included_reader_hh
#define already_included_reader_hh

class Gulper
{
public:
   virtual ~Gulper() {}
   virtual int gulp_char() = null;
};

class FileGulper : public Gulper
{
private:
   FILE* f;
   bool ours_to_close;
public:
   FileGulper(string file_name);
   FileGulper(const char* file_name);
   FileGulper(FILE* f);
   ~FileGulper();
   int gulp_char();
};

class Reader_core
{
private:
   enum Return_values {
      TT_eof = -1, TT_void=256, TT_char, TT_int, TT_double,
      TT_identifier, TT_string, TT_bool,
   };

Gulper*       reader;
   int           current;
   Return_values current_type;
   string        file_name;

public:
   Reader_core(string file_name);
   ~Reader_core();

bool currently_bool()       { return current_type == TT_bool; }
   bool currently_char()       { return current_type == TT_char; }
   bool currently_int()        { return current_type == TT_int; }
   bool currently_double()     { return current_type == TT_double; }
   bool currently_identifier() { return current_type == TT_identifier; }
   bool currently_string()     { return current_type == TT_string; }
   bool currently_eof()        { return current_type == TT_eof; }

bool   peek_bool();
   char   peek_char();
   int    peek_int();
   double peek_double();
   string peek_identifier();
   string peek_string();

void   next_token();
   int    get_file_line();
   string get_file_name();

private:
   void        skip_whitespace();
   int         scan_int();
   double      scan_fraction();
   string      scan_identifier();
   string      scan_quoted_string();
   double      fractionalise(int i);
   void        gulp();
   void        wrong_type(string tname);
   /* DIAGNOSTICS: */
   void   error(string s);
   string debug_say_symbol();

char        last_char;
   int         last_int;
   double      last_double;
   string      last_identifier;
   string      last_string;
   bool        last_bool;
   int         current_line;
   string      current_file;
};

class Reader : public Reader_core
{
public:
   Reader(string file_name) : Reader_core(file_name) {}
   /* PEEKING: */
   bool looking_at(char ch);
   bool looking_at(string s);
   /* READING LITERALS: */
   friend Reader& operator>>(Reader& r, const char& ch);
   friend Reader& operator>>(Reader& r, const char* s);
   /* GULPING DATA: */
   friend Reader& operator>>(Reader& r, bool& b);
   friend Reader& operator>>(Reader& r, char& ch);
   friend Reader& operator>>(Reader& r, int& i);
   friend Reader& operator>>(Reader& r, double& d);
   friend Reader& operator>>(Reader& r, string& s);
   string gulp_quoted_string();
};

#endif /* already_included_reader_hh */