sli_scanner.h

/*
 *  scanner.h
 *
 *  This file is part of NEST
 *
 *  Copyright (C) 2004 by
 *  The NEST Initiative
 *
 *  See the file AUTHORS for details.
 *
 *  Permission is granted to compile and modify
 *  this file for non-commercial use.
 *  See the file LICENSE for details.
 *
 */

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

*/
#include "sli_token.h"
#include "sli_name.h"
#include "sli_charcode.h"

#include <iostream>
#include <string>

namespace sli3
{
  class SLIInterpreter;

  class Scanner 
  {
    std::istream* in;
    
    CharCode code;             // some Chars cause the same Transition 
    
    unsigned long line; //!< Current line number
    unsigned long col;  //!< Current column in line
    std::string   context; //!< Current 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,
      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';}
    
    std::string ds;
    
  public:
    Name BeginArraySymbol;
    Name EndArraySymbol;
    Name BeginProcedureSymbol;
    Name EndProcedureSymbol;
    Name EndSymbol;
    
    /**
     * Initialise scanner with a stream. 
     */
    Scanner(std::istream *);
    
    /**
     * Set new input stream.
     */
    void source(std::istream *);
    
    /**
     * Return input stream.
     */
    std::istream* GetSource(void) {return in; }
    
    /**
     * Scan input until the next Token.
     */
    bool     operator()(SLIInterpreter &, Token&);
    
    /**
     * Issue an error message.
     */
    void print_error(const char *);
    
    /**
     * Return current line number in input stream.
     */
    unsigned long get_line() const
    {
      return line;
    }
    
    /**
     * Return position in  current line in input stream.
     */
    unsigned long get_col() const
    {
      return col;
    }
    
    void clear_context()
    {
      line=0;
      col=0;
      context.clear();
      old_context.clear();
    }
  };
}
# endif