scanner.h

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/*
 *  scanner.h
 *
 *  This file is part of NEST.
 *
 *  Copyright (C) 2004 The NEST Initiative
 *
 *  NEST is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  NEST is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with NEST.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

# ifndef Scanner_H
#define Scanner_H
/* 
    SLI's lexical analyzer

*/
#include <typeinfo>
#include <iostream>
#include <string>

#include "token.h"
#include "symboldatum.h"
#include "charcode.h"


class Scanner 
{
  std::istream* in;
  
  CharCode code;             // some Chars cause the same Transition 

  unsigned long line; 
  unsigned long col;  
  std::string   context; 
  std::string   old_context;
  enum ScanStates {
    start=0, 
    intdgtst,
    intexpst,
    nullst,
    aheadintst,
    decpfirstst,
    decpdgtst,
    decpointst,
    fracdgtst,
    minusst,
    plusst,
    aheadsgst,
    sgalphast,
    aheadfracst,
    expntlst,
    plexpst,
    mnexpst,
    openbracketst,
    closebracketst,
    openbracest,
    closebracest,
    openparst,
    closeparst,
    expdigst,
    dotalphast,
    alphast,
    aheadalphst,
    slashst,
    literalst,
    aheadlitst,
    percentst,
    whitest,
    asteriskst,
    ccommentst,
    startstringst,
    stringst,
    backslashst,
    newlinest,
    tabulatorst,
    backslashcst,
    oparenthcst,
    cparenthcst,
    end,
    eofst,
    error,
    lastscanstate
  };

  enum Codes {
    invalid=0,
    whitespace,
    eof,
    digit,
    null,
    expntl,
    decpoint,
    plus,
    minus,
    openbracket,
    closebracket,
    openbrace,
    closebrace,
    openparenth,
    closeparenth,
    alpha,
    slash,
    backslash,
    newline,
    tabulator,
    asterisk,
    percent,
    eoln,
    other,
    lastcode
  };
  
  enum ScanStates trans[lastscanstate][lastcode];     // DFA transition-function



  
  const unsigned char space;
  const unsigned char tab;
  const unsigned char endoln;
  const unsigned char cr; // carriage return (ctrl M)
  const unsigned char endof;
  int digval(unsigned char c) const 
  {return c-'0';}



public:
  SymbolDatum BeginArraySymbol;
  SymbolDatum EndArraySymbol;
  SymbolDatum BeginProcedureSymbol;
  SymbolDatum EndProcedureSymbol;
  SymbolDatum EndSymbol;
  
  Scanner(std::istream *);

  void source(std::istream *);

  std::istream* GetSource(void) {return in; }

  bool     operator()(Token&);

  void print_error(const char *);

  unsigned long get_line() const
  {
    return line;
  }

  unsigned long get_col() const
  {
    return col;
  }

  void clear_context()
  {
    line=0;
    col=0;
    context.clear();
    old_context.clear();
  }
};

# endif