Statement.java

package calculator.interpreter.ast;

import java.util.LinkedList;
import calculator.interpreter.Cell;
import calculator.interpreter.Environment;
import calculator.interpreter.ast.meta.Annotation;
import calculator.interpreter.ast.meta.DocumentationLine;

/**
 * The base statement class
 */
public abstract class Statement extends Node {
  /** the annotations associated with statement */
  public final LinkedList<Annotation> annotations = new LinkedList<Annotation>();
  /** the documentation lines associated with statement */
  public final LinkedList<DocumentationLine> documentation = new LinkedList<DocumentationLine>();

  /**
   * @return true if the statement has metadata
   */
  public boolean hasMetadata() {
    return !annotations.isEmpty() || !documentation.isEmpty();
  }

  /**
   * The evaluate statement
   * 
   * @param env the evaluation environment
   * @param result the evaluation result (the cell might be null, in that case
   *          the result must be discarded).
   * @return new context (if environment is not changed returns {@code env}
   *         argument)
   */
  public abstract Environment eval(Environment env, Cell result);
}