localvariable.java

一个JAVA编写的简单编译器

package ast.declaration;

public class LocalVariable extends ast.declaration.JSubObject {
  private boolean iAmAParameter;
  private static int currentNoInThisLevel;
  private int no; // current number of varible
  
  // to count local Variable. 0 = this, 
  public static void reset () {
    currentNoInThisLevel = 0;
  }
  
  public LocalVariable (String name, boolean iAmAParameter) {
    super (name, ast.declaration.JSubObject.TINT);
    this.iAmAParameter = iAmAParameter;
    no = currentNoInThisLevel++;
  }
  
  public String toString () {
    return "" + no;
  }
    
  public void dump (String prefix) {
    char c = ' ';
    if (iAmAParameter)
      c = 'p';
    System.out.print ("local" + c + ' ' + no + " ");
    super.dump (prefix);
  }
  public void genXML (java.io.PrintStream p, String prefix) {
    p.println (prefix + "<localvariable name = \"" + getName () +"\"/>");
  }

  public boolean isParameter () {
    return iAmAParameter;
  }

  public String getStoreString () {
    StringBuffer buffer = new StringBuffer ("istore");
    if (no <= 3)
      buffer.append ('_');//istroe_0,1,2,3 pop int to local variable position 0,1,2,3.
     else
       buffer.append (' ');//it is functionally equivalent to istore_
    buffer.append (no);
    return buffer.toString ();
  }
  public String getLoadString () {
    StringBuffer buffer = new StringBuffer ("iload");
    if (no <= 3)
      buffer.append ('_');//iload_0,1,2,3 pushes int from local variable position 0,1,2,3.
     else
       buffer.append (' ');//it is functionally equivalent to iload_
    buffer.append (no);
    return buffer.toString ();
  }
   public String getXMLType () {
    return "local";
  }

}