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Create Your Own Programming Language

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4.87/5 (53 votes)
21 Jan 2010CPOL12 min read 484.4K   15.4K   87  
I've created my own programming language called Alef++ for fun, and for better understanding: What is a programing language? How does it work? Can I can create my own?
/* Generated By:JavaCC: Do not edit this line. SimpleCharStream.java Version 4.1 */
/* JavaCCOptions:STATIC=false */
package st4tic;

/**
 * An implementation of interface CharStream, where the stream is assumed to
 * contain only ASCII characters (without unicode processing).
 */

public class SimpleCharStream
{
/** Whether parser is static. */
  public static final boolean staticFlag = false;
  int bufsize;
  int available;
  int tokenBegin;
/** Position in buffer. */
  public int bufpos = -1;
  protected int bufline[];
  protected int bufcolumn[];

  protected int column = 0;
  protected int line = 1;

  protected boolean prevCharIsCR = false;
  protected boolean prevCharIsLF = false;

  protected java.io.Reader inputStream;

  protected char[] buffer;
  protected int maxNextCharInd = 0;
  protected int inBuf = 0;
  protected int tabSize = 8;

  protected void setTabSize(int i) { tabSize = i; }
  protected int getTabSize(int i) { return tabSize; }


  protected void ExpandBuff(boolean wrapAround)
  {
     char[] newbuffer = new char[bufsize + 2048];
     int newbufline[] = new int[bufsize + 2048];
     int newbufcolumn[] = new int[bufsize + 2048];

     try
     {
        if (wrapAround)
        {
           System.arraycopy(buffer, tokenBegin, newbuffer, 0, bufsize - tokenBegin);
           System.arraycopy(buffer, 0, newbuffer,
                                             bufsize - tokenBegin, bufpos);
           buffer = newbuffer;

           System.arraycopy(bufline, tokenBegin, newbufline, 0, bufsize - tokenBegin);
           System.arraycopy(bufline, 0, newbufline, bufsize - tokenBegin, bufpos);
           bufline = newbufline;

           System.arraycopy(bufcolumn, tokenBegin, newbufcolumn, 0, bufsize - tokenBegin);
           System.arraycopy(bufcolumn, 0, newbufcolumn, bufsize - tokenBegin, bufpos);
           bufcolumn = newbufcolumn;

           maxNextCharInd = (bufpos += (bufsize - tokenBegin));
        }
        else
        {
           System.arraycopy(buffer, tokenBegin, newbuffer, 0, bufsize - tokenBegin);
           buffer = newbuffer;

           System.arraycopy(bufline, tokenBegin, newbufline, 0, bufsize - tokenBegin);
           bufline = newbufline;

           System.arraycopy(bufcolumn, tokenBegin, newbufcolumn, 0, bufsize - tokenBegin);
           bufcolumn = newbufcolumn;

           maxNextCharInd = (bufpos -= tokenBegin);
        }
     }
     catch (Throwable t)
     {
        throw new Error(t.getMessage());
     }


     bufsize += 2048;
     available = bufsize;
     tokenBegin = 0;
  }

  protected void FillBuff() throws java.io.IOException
  {
     if (maxNextCharInd == available)
     {
        if (available == bufsize)
        {
           if (tokenBegin > 2048)
           {
              bufpos = maxNextCharInd = 0;
              available = tokenBegin;
           }
           else if (tokenBegin < 0)
              bufpos = maxNextCharInd = 0;
           else
              ExpandBuff(false);
        }
        else if (available > tokenBegin)
           available = bufsize;
        else if ((tokenBegin - available) < 2048)
           ExpandBuff(true);
        else
           available = tokenBegin;
     }

     int i;
     try {
        if ((i = inputStream.read(buffer, maxNextCharInd,
                                    available - maxNextCharInd)) == -1)
        {
           inputStream.close();
           throw new java.io.IOException();
        }
        else
           maxNextCharInd += i;
        return;
     }
     catch(java.io.IOException e) {
        --bufpos;
        backup(0);
        if (tokenBegin == -1)
           tokenBegin = bufpos;
        throw e;
     }
  }

/** Start. */
  public char BeginToken() throws java.io.IOException
  {
     tokenBegin = -1;
     char c = readChar();
     tokenBegin = bufpos;

     return c;
  }

  protected void UpdateLineColumn(char c)
  {
     column++;

     if (prevCharIsLF)
     {
        prevCharIsLF = false;
        line += (column = 1);
     }
     else if (prevCharIsCR)
     {
        prevCharIsCR = false;
        if (c == '\n')
        {
           prevCharIsLF = true;
        }
        else
           line += (column = 1);
     }

     switch (c)
     {
        case '\r' :
           prevCharIsCR = true;
           break;
        case '\n' :
           prevCharIsLF = true;
           break;
        case '\t' :
           column--;
           column += (tabSize - (column % tabSize));
           break;
        default :
           break;
     }

     bufline[bufpos] = line;
     bufcolumn[bufpos] = column;
  }

/** Read a character. */
  public char readChar() throws java.io.IOException
  {
     if (inBuf > 0)
     {
        --inBuf;

        if (++bufpos == bufsize)
           bufpos = 0;

        return buffer[bufpos];
     }

     if (++bufpos >= maxNextCharInd)
        FillBuff();

     char c = buffer[bufpos];

     UpdateLineColumn(c);
     return c;
  }

  /**
   * @deprecated 
   * @see #getEndColumn
   */

  public int getColumn() {
     return bufcolumn[bufpos];
  }

  /**
   * @deprecated 
   * @see #getEndLine
   */

  public int getLine() {
     return bufline[bufpos];
  }

  /** Get token end column number. */
  public int getEndColumn() {
     return bufcolumn[bufpos];
  }

  /** Get token end line number. */
  public int getEndLine() {
     return bufline[bufpos];
  }

  /** Get token beginning column number. */
  public int getBeginColumn() {
     return bufcolumn[tokenBegin];
  }

  /** Get token beginning line number. */
  public int getBeginLine() {
     return bufline[tokenBegin];
  }

/** Backup a number of characters. */
  public void backup(int amount) {

    inBuf += amount;
    if ((bufpos -= amount) < 0)
       bufpos += bufsize;
  }

  /** Constructor. */
  public SimpleCharStream(java.io.Reader dstream, int startline,
  int startcolumn, int buffersize)
  {
    inputStream = dstream;
    line = startline;
    column = startcolumn - 1;

    available = bufsize = buffersize;
    buffer = new char[buffersize];
    bufline = new int[buffersize];
    bufcolumn = new int[buffersize];
  }

  /** Constructor. */
  public SimpleCharStream(java.io.Reader dstream, int startline,
                          int startcolumn)
  {
     this(dstream, startline, startcolumn, 4096);
  }

  /** Constructor. */
  public SimpleCharStream(java.io.Reader dstream)
  {
     this(dstream, 1, 1, 4096);
  }

  /** Reinitialise. */
  public void ReInit(java.io.Reader dstream, int startline,
  int startcolumn, int buffersize)
  {
    inputStream = dstream;
    line = startline;
    column = startcolumn - 1;

    if (buffer == null || buffersize != buffer.length)
    {
      available = bufsize = buffersize;
      buffer = new char[buffersize];
      bufline = new int[buffersize];
      bufcolumn = new int[buffersize];
    }
    prevCharIsLF = prevCharIsCR = false;
    tokenBegin = inBuf = maxNextCharInd = 0;
    bufpos = -1;
  }

  /** Reinitialise. */
  public void ReInit(java.io.Reader dstream, int startline,
                     int startcolumn)
  {
     ReInit(dstream, startline, startcolumn, 4096);
  }

  /** Reinitialise. */
  public void ReInit(java.io.Reader dstream)
  {
     ReInit(dstream, 1, 1, 4096);
  }
  /** Constructor. */
  public SimpleCharStream(java.io.InputStream dstream, String encoding, int startline,
  int startcolumn, int buffersize) throws java.io.UnsupportedEncodingException
  {
     this(encoding == null ? new java.io.InputStreamReader(dstream) : new java.io.InputStreamReader(dstream, encoding), startline, startcolumn, buffersize);
  }

  /** Constructor. */
  public SimpleCharStream(java.io.InputStream dstream, int startline,
  int startcolumn, int buffersize)
  {
     this(new java.io.InputStreamReader(dstream), startline, startcolumn, buffersize);
  }

  /** Constructor. */
  public SimpleCharStream(java.io.InputStream dstream, String encoding, int startline,
                          int startcolumn) throws java.io.UnsupportedEncodingException
  {
     this(dstream, encoding, startline, startcolumn, 4096);
  }

  /** Constructor. */
  public SimpleCharStream(java.io.InputStream dstream, int startline,
                          int startcolumn)
  {
     this(dstream, startline, startcolumn, 4096);
  }

  /** Constructor. */
  public SimpleCharStream(java.io.InputStream dstream, String encoding) throws java.io.UnsupportedEncodingException
  {
     this(dstream, encoding, 1, 1, 4096);
  }

  /** Constructor. */
  public SimpleCharStream(java.io.InputStream dstream)
  {
     this(dstream, 1, 1, 4096);
  }

  /** Reinitialise. */
  public void ReInit(java.io.InputStream dstream, String encoding, int startline,
                          int startcolumn, int buffersize) throws java.io.UnsupportedEncodingException
  {
     ReInit(encoding == null ? new java.io.InputStreamReader(dstream) : new java.io.InputStreamReader(dstream, encoding), startline, startcolumn, buffersize);
  }

  /** Reinitialise. */
  public void ReInit(java.io.InputStream dstream, int startline,
                          int startcolumn, int buffersize)
  {
     ReInit(new java.io.InputStreamReader(dstream), startline, startcolumn, buffersize);
  }

  /** Reinitialise. */
  public void ReInit(java.io.InputStream dstream, String encoding) throws java.io.UnsupportedEncodingException
  {
     ReInit(dstream, encoding, 1, 1, 4096);
  }

  /** Reinitialise. */
  public void ReInit(java.io.InputStream dstream)
  {
     ReInit(dstream, 1, 1, 4096);
  }
  /** Reinitialise. */
  public void ReInit(java.io.InputStream dstream, String encoding, int startline,
                     int startcolumn) throws java.io.UnsupportedEncodingException
  {
     ReInit(dstream, encoding, startline, startcolumn, 4096);
  }
  /** Reinitialise. */
  public void ReInit(java.io.InputStream dstream, int startline,
                     int startcolumn)
  {
     ReInit(dstream, startline, startcolumn, 4096);
  }
  /** Get token literal value. */
  public String GetImage()
  {
     if (bufpos >= tokenBegin)
        return new String(buffer, tokenBegin, bufpos - tokenBegin + 1);
     else
        return new String(buffer, tokenBegin, bufsize - tokenBegin) +
                              new String(buffer, 0, bufpos + 1);
  }

  /** Get the suffix. */
  public char[] GetSuffix(int len)
  {
     char[] ret = new char[len];

     if ((bufpos + 1) >= len)
        System.arraycopy(buffer, bufpos - len + 1, ret, 0, len);
     else
     {
        System.arraycopy(buffer, bufsize - (len - bufpos - 1), ret, 0,
                                                          len - bufpos - 1);
        System.arraycopy(buffer, 0, ret, len - bufpos - 1, bufpos + 1);
     }

     return ret;
  }

  /** Reset buffer when finished. */
  public void Done()
  {
     buffer = null;
     bufline = null;
     bufcolumn = null;
  }

  /**
   * Method to adjust line and column numbers for the start of a token.
   */
  public void adjustBeginLineColumn(int newLine, int newCol)
  {
     int start = tokenBegin;
     int len;

     if (bufpos >= tokenBegin)
     {
        len = bufpos - tokenBegin + inBuf + 1;
     }
     else
     {
        len = bufsize - tokenBegin + bufpos + 1 + inBuf;
     }

     int i = 0, j = 0, k = 0;
     int nextColDiff = 0, columnDiff = 0;

     while (i < len &&
            bufline[j = start % bufsize] == bufline[k = ++start % bufsize])
     {
        bufline[j] = newLine;
        nextColDiff = columnDiff + bufcolumn[k] - bufcolumn[j];
        bufcolumn[j] = newCol + columnDiff;
        columnDiff = nextColDiff;
        i++;
     } 

     if (i < len)
     {
        bufline[j] = newLine++;
        bufcolumn[j] = newCol + columnDiff;

        while (i++ < len)
        {
           if (bufline[j = start % bufsize] != bufline[++start % bufsize])
              bufline[j] = newLine++;
           else
              bufline[j] = newLine;
        }
     }

     line = bufline[j];
     column = bufcolumn[j];
  }

}
/* JavaCC - OriginalChecksum=7dbc403b403ba9f8a35ae72ef1961d10 (do not edit this line) */

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License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Technical Lead
Morocco Morocco
Adrabi!, Just another Ghost in the Shell =)

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