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// $Id: lexer.cpp 1025 2007-04-30 14:48:32Z hiker $
//
// TuxKart - a fun racing game with go-kart
// Copyright (C) 2004 Matthias Braun <matze@braunis.de>
// code in this file based on lispreader from Mark Probst
//
// This program 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.
//
// This program 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 this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#include <sstream>
#include <stdexcept>
#include "lexer.hpp"
#include "translation.hpp"
#if defined(WIN32) && !defined(__CYGWIN__)
# define snprintf _snprintf
#endif
namespace lisp
{
class EOFException
{}
;
Lexer::Lexer(std::istream& newstream)
: m_stream(newstream), m_is_eof(false)
{
try
{
// trigger a refill of the m_buffer
m_c = 0;
m_buffer_end = m_c + 1;
nextChar();
}
catch(EOFException& e)
{}
}
//-----------------------------------------------------------------------------
Lexer::~Lexer()
{}
//-----------------------------------------------------------------------------
void
Lexer::nextChar()
{
++m_c;
if(m_c >= m_buffer_end)
{
if(m_is_eof)
throw EOFException();
m_stream.read(m_buffer, LEXER_BUFFER_SIZE);
std::streamsize n = m_stream.gcount();
m_c = m_buffer;
m_buffer_end = m_buffer + n;
// the following is a hack that appends an additional ' ' at the end of
// the file to avoid problems when parsing symbols/elements and a sudden
// EOF. This is faster than relying on unget and IMO also nicer.
if(n < LEXER_BUFFER_SIZE || n == 0)
{
*m_buffer_end = ' ';
++m_buffer_end;
m_is_eof = true;
}
}
}
//-----------------------------------------------------------------------------
Lexer::TokenType
Lexer::getNextToken()
{
static const char* delims = "\"();";
try
{
while(isspace(*m_c))
{
nextChar();
if(*m_c == '\n')
++m_line_number;
};
m_token_length = 0;
switch(*m_c)
{
case ';': // comment
while(true)
{
nextChar();
if(*m_c == '\n')
{
++m_line_number;
break;
}
}
return getNextToken(); // and again
case '(':
nextChar();
return TOKEN_OPEN_PAREN;
case ')':
nextChar();
return TOKEN_CLOSE_PAREN;
case '"': // string
{
const int STARTLINE = m_line_number;
try
{
while(1)
{
nextChar();
if(*m_c == '"')
break;
if(*m_c == '\\')
{
nextChar();
switch(*m_c)
{
case 'n':
*m_c = '\n';
break;
case 't':
*m_c = '\t';
break;
}
}
if(m_token_length < MAX_TOKEN_LENGTH)
m_token_string[m_token_length++] = *m_c;
}
m_token_string[m_token_length] = 0;
}
catch(EOFException& )
{
char msg[MAX_ERROR_MESSAGE_LENGTH];
snprintf(msg, sizeof(msg),
"Parse error in line %d: EOF while parsing string.",
STARTLINE);
throw std::runtime_error(msg);
}
nextChar();
return TOKEN_STRING;
}
case '#': // constant
try
{
nextChar();
while(isalnum(*m_c) || *m_c == '_')
{
if(m_token_length < MAX_TOKEN_LENGTH)
m_token_string[m_token_length++] = *m_c;
nextChar();
}
m_token_string[m_token_length] = 0;
}
catch(EOFException& )
{
char msg[MAX_ERROR_MESSAGE_LENGTH];
snprintf(msg, sizeof(msg),
"Parse Error in line %d: EOF while parsing constant.",
m_line_number);
throw std::runtime_error(msg);
}
if(strcmp(m_token_string, "t") == 0)
return TOKEN_TRUE;
if(strcmp(m_token_string, "f") == 0)
return TOKEN_FALSE;
// this would be the place to add more sophisticated handling of
// constants
{
char msg[MAX_ERROR_MESSAGE_LENGTH];
snprintf(msg, sizeof(msg),
"Parse Error in line %d: Unknown constant '%s'.",
m_line_number, m_token_string);
throw std::runtime_error(msg);
}
default:
if(isdigit(*m_c) || *m_c == '-')
{
bool have_nondigits = false;
bool have_digits = false;
int have_floating_point = 0;
do
{
if(isdigit(*m_c))
have_digits = true;
else if(*m_c == '.')
++have_floating_point;
else if(isalnum(*m_c) || *m_c == '_')
have_nondigits = true;
if(m_token_length < MAX_TOKEN_LENGTH)
m_token_string[m_token_length++] = *m_c;
nextChar();
}
while(!isspace(*m_c) && !strchr(delims, *m_c));
m_token_string[m_token_length] = 0;
// no nextChar
if(have_nondigits || !have_digits || have_floating_point > 1)
return TOKEN_SYMBOL;
else if(have_floating_point == 1)
return TOKEN_REAL;
else
return TOKEN_INTEGER;
}
else
{
do
{
if(m_token_length < MAX_TOKEN_LENGTH)
m_token_string[m_token_length++] = *m_c;
nextChar();
}
while(!isspace(*m_c) && !strchr(delims, *m_c));
m_token_string[m_token_length] = 0;
// no nextChar
return TOKEN_SYMBOL;
}
}
}
catch(EOFException& )
{
return TOKEN_EOF;
}
}
} // end of namespace lisp
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