package LBJ2.IR;

import LBJ2.Pass;


/**
  * An expression statement is a statement composed only of a single
  * expression, as opposed to a statement involving control flow.
  *
  * @author Nick Rizzolo
 **/
public class ExpressionStatement extends Statement
{
  /** (¬ø) The expression being used as a statement. */
  public StatementExpression expression;


  /**
    * Initializing constructor.  Line and byte offset information are taken
    * from the expression's representation.
    *
    * @param e  The expression being used as a statement.
   **/
  public ExpressionStatement(StatementExpression e) {
    super(e.line, e.byteOffset);
    expression = e;
  }


  /**
    * Returns an iterator used to successively access the children of this
    * node.
    *
    * @return An iterator used to successively access the children of this
    *         node.
   **/
  public ASTNodeIterator iterator() {
    ASTNodeIterator I = new ASTNodeIterator(1);
    I.children[0] = expression;
    return I;
  }


  /**
    * Creates a new object with the same primitive data, and recursively
    * creates new member data objects as well.
    *
    * @return The clone node.
   **/
  public Object clone() {
    return new ExpressionStatement((StatementExpression) expression.clone());
  }


  /** Returns a hash code for this {@link ASTNode}. */
  public int hashCode() {
    return 31 * expression.hashCode();
  }


  /**
    * Distinguishes this {@link ASTNode} from other objects according to its
    * contents recursively.
    *
    * @param o  Another object.
    * @return <code>true</code> iff this node is equal to <code>o</code>.
   **/
  public boolean equals(Object o) {
    if (!(o instanceof ExpressionStatement)) return false;
    ExpressionStatement e = (ExpressionStatement) o;
    return expression.equals(e.expression);
  }


  /**
    * Ensures that the correct <code>run()</code> method is called for this
    * type of node.
    *
    * @param pass The pass whose <code>run()</code> method should be called.
   **/
  public void runPass(Pass pass) { pass.run(this); }


  /**
    * Writes a string representation of this <code>ASTNode</code> to the
    * specified buffer.  The representation written is parsable by the LBJ2
    * compiler, but not very readable.
    *
    * @param buffer The buffer to write to.
   **/
  public void write(StringBuffer buffer) {
    expression.write(buffer);
    buffer.append(";");
  }
}