SimpleParser.h

#ifndef UTILS_SIMPLE_PARSER_H
#define UTILS_SIMPLE_PARSER_H

#include <iosfwd>
#include <ctype.h>
#include <assert.h>
#include <string>
using namespace std;

class SimpleParser
{
public:
  enum Result { Continue, Stop, Error };
  SimpleParser(istream& in);
  virtual ~SimpleParser() {}
  virtual bool IsSpace(char c) const { return isspace(c); }
  virtual bool IsComment(char c) const { return c=='#'; }
  virtual bool IsToken(char c) const { return isalnum(c); }
  virtual bool IsPunct(char c) const { return !IsSpace(c) && !IsComment(c) && !IsToken(c); }
  virtual Result InputToken(const string& word)=0;
  virtual Result InputPunct(const string& punct)=0;
  virtual Result InputEndLine()=0;

  bool Read();

  //called by sub classes on error, stop
  bool EatSpace();
  bool ReadLine(string& str);

  istream& in;
  int lineno;
};

#endif