codefrags.h

用于词法分析的词法分析器

/*
  $Id: CodeFrags.h,v 1.2 1996/07/27 07:26:28 matt Exp $

  Code frags handler class.

  (c) Matt Phillips 1996.
  */

#ifndef _CODE_FRAGS
#define _CODE_FRAGS

#include <istream.h>
#include <std/string.h>

// code frags example:
//
//  *
//  cpp
//  > a c++ code frag
//  > a c++ code frag
//  ada
//  > an ada code frag
//  *
//  c
//  > a c code frag

class CodeFrags
{
public:

  // an object reading from <i> looking for fragments of language <l>.
  CodeFrags (istream &i, const string &l) :
    input (i), lang (l) {atFrag = 0;}

  // jump to next code fragment (if any).
  int nextFrag ();
  
  // true if the previous nextFrag () found a code fragment.
  int hasFrag () const {return atFrag;}
  
  // output a fragment found by nextFrag () to <output>.  does nothing
  // if no fragment was found.
  void outputFrag (ostream &output);

  // true if the code frags file has been fully processed.
  int eof () const {return input.eof ();}

protected:

  istream &input;
  const string lang;
  string line;
  int atFrag;

  void nextSection ();
};

#endif