/* Lexer.cc -- simple lexer for 8-puzzle test language. -*- c++ -*-
   Copyright (C) 2007  Casey Marshall <csm@soe.ucsc.edu> */

#include <string>
#include <sstream>
#include "Lexer.h"

static std::string inputString;
static int inputIndex;

void
Lexer::setInputString(std::string& input)
{
  inputString = input;
  inputIndex = 0;
}

void
Lexer::nextToken(LexerInterface *lex)
{
  if (inputString.length() <= inputIndex)
    {
      lex->type = TOK_EOF;
      return;
    }

  while (true)
    {
      char c = inputString[inputIndex];
      std::cerr << "process char " << c << std::endl;
      switch ((c = inputString[inputIndex++]))
        {
        case '+': lex->type = TOK_PLUS; return;
        case '-': lex->type = TOK_MINUS; return;
        case '*': lex->type = TOK_TIMES; return;
        case '/': lex->type = TOK_DIVIDE; return;
        case 'e': lex->type = TOK_EDGE; return;
        case 'm': lex->type = TOK_MANHATTAN; return;
        case 'M': lex->type = TOK_MANHATTAN2; return;
        case 'n': lex->type = TOK_NEIGHBOR; return;
        case 'N': lex->type = TOK_NEIGHBOR2; return;
        case '(': lex->type = TOK_LPAREN; return;
        case ')': lex->type = TOK_RPAREN; return;

        case '0':
        case '1':
        case '2':
        case '3':
        case '4':
        case '5':
        case '6':
        case '7':
        case '8':
        case '9':
          {
            std::string val;
            val.append(1, c);
            bool saw_dot = false;
            for (; inputIndex < inputString.length(); inputIndex++)
              {
                char cc = inputString[inputIndex];
                if (isdigit(cc))
                  val.append(1, cc);
                else if (cc == '.')
                  {
                    if (saw_dot)
                      {
                        throw "malformed input; two decimals seen in a double";
                      }
                    saw_dot = true;
                    val.append(1, cc);
                  }
                else
                  break;
              }
            double *value = (double *) malloc(sizeof(double));
            std::istringstream in(val);
            in >> (*value);
            
            lex->type = TOK_LITERAL;
            lex->sval = (SemanticValue) value;
          }
          return;
          
        default:
          if (!isspace(c))
            throw "invalid character in input";
        }
    }
}

string
Lexer::tokenDesc() const
{
  return string("");
}

string
Lexer::tokenKindDesc(int kind) const
{
  return string("");
}