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/* XLogo4Schools - A Logo Interpreter specialized for use in schools, based on XLogo by Lo�c Le Coq
* Copyright (C) 2013 Marko Zivkovic
*
* Contact Information: marko88zivkovic at gmail dot com
*
* 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., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*
*
* This Java source code belongs to XLogo4Schools, written by Marko Zivkovic
* during his Bachelor thesis at the computer science department of ETH Z�rich,
* in the year 2013 and/or during future work.
*
* It is a reengineered version of XLogo written by Lo�c Le Coq, published
* under the GPL License at http://xlogo.tuxfamily.org/
*
* Contents of this file were initially written by Lo�c Le Coq,
* modifications, extensions, refactorings might have been applied by Marko Zivkovic
*/
/**
* Title : XLogo
* Description : XLogo is an interpreter for the Logo
* programming language
*
* @author Loïc Le Coq
*/
package xlogo.kernel.grammar;
import xlogo.Logo;
import xlogo.kernel.DrawPanel;
import xlogo.kernel.Primitive;
import xlogo.storage.global.GlobalConfig;
public class LogoParser
{
private char c;
private int cursor;
private String text;
/**
*
* @param sr
* The String input reader
*/
public LogoParser(String text)
{
this.text = text;
cursor = 0;
while (cursor < text.length())
{
LogoType lt = getToken();
if (GlobalConfig.DEBUG)
System.out.println("[DEBUG] Token " + lt.toDebug() + " cursor " + cursor);
}
}
private LogoType getToken()
{
boolean isQuotedWord = false;
boolean isVariable = false;
StringBuffer sb = new StringBuffer();
boolean start = false;
boolean backslash = false;
do
{
c = text.charAt(cursor);
// Skip White Spaces
if (c == ' ' || c == '\t')
{
if (start)
break;
else
cursor++;
}
else
{
if (backslash)
{
if (c == ' ')
sb.append(" ");
else if (c == '#')
sb.append("#");
else if (c == '\\')
sb.append("\\");
else if (c == '(')
sb.append("(");
else if (c == ')')
sb.append(")");
else if (c == '[')
sb.append("[");
else if (c == ']')
sb.append("]");
else if (c == 'n')
sb.append("\n");
else
sb.append(c);
cursor++;
}
else
{
// If it's the first character, check for type
if (!start)
{
if (c == ':')
isVariable = true;
else if (c == '\"')
isQuotedWord = true;
}
if (c == '\\')
backslash = true;
else if (c == '[')
{
if (start)
break;
else
{
cursor++;
return extractList();
}
}
else if (c == '(')
{
if (start)
break;
}
else if (c == '*' || c == '/' || c == '+' || c == '-' || c == '|' || c == '&' || c == '=')
{
if (!isQuotedWord)
{
if (!start)
{
sb.append(c);
cursor++;
}
break;
}
else
cursor++;
}
else if (c == ')')
return new LogoException(Logo.messages.getString("parenthese_ouvrante"));
else if (c == ']')
return new LogoException(Logo.messages.getString("error.whattodo") + " ]");
else
{
sb.append(c);
cursor++;
}
}
start = true;
}
} while (cursor < text.length());
if (sb.length() == 0)
return DrawPanel.nullType;
else if (isQuotedWord)
return new LogoWord(sb.substring(1));
else if (isVariable)
return new LogoVariable(sb.substring(1));
try
{
double d = Double.parseDouble(sb.toString());
return new LogoNumber(d);
}
catch (NumberFormatException e)
{
int id = Primitive.isPrimitive(sb.toString());
if (id != -1) { return new LogoPrimitive(id, sb.toString()); }
return new LogoException(Logo.messages.getString("je_ne_sais_pas") + " " + sb.toString());
}
}
/**
* This method extracts a list.
*
* @return a LogoList if operation succeed,
* a LogoException otherwise
*/
private LogoType extractList()
{
LogoList list = new LogoList();
while (cursor < text.length())
{
LogoType lt = getListToken();
if (lt.isNull())
{
return new LogoException(Logo.messages.getString("erreur_crochet"));
}
else if (lt.isRightDelimiter())
return list;
else
{
list.add(lt);
}
}
return new LogoException(Logo.messages.getString("erreur_crochet"));
}
private LogoType getListToken()
{
StringBuffer sb = new StringBuffer();
boolean start = false;
boolean backslash = false;
for (int i = cursor; i < text.length(); i++)
{
cursor = i;
c = text.charAt(i);
// Skip White Spaces
if (c == ' ' || c == '\t')
{
if (start)
break;
}
else
{
if (backslash)
{
if (c == ' ')
sb.append(" ");
else if (c == '#')
sb.append("#");
else if (c == '\\')
sb.append("\\");
else if (c == '(')
sb.append("(");
else if (c == ')')
sb.append(")");
else if (c == '[')
sb.append("[");
else if (c == ']')
sb.append("]");
else if (c == 'n')
sb.append("\n");
else
sb.append(c);
}
else
{
if (c == '\\')
{
backslash = true;
}
else if (c == '[')
{
if (start)
break;
else
{
cursor++;
return extractList();
}
}
else if (c == ']')
{
if (start)
break;
else
{
System.out.println("coucou");
cursor++;
return new LogoRightDelimiter();
}
}
else
sb.append(c);
}
start = true;
}
}
if (sb.length() == 0)
return DrawPanel.nullType;
return new LogoWord(sb.toString());
}
}
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