// file:    squares.java
// author:  Robert Keller
// purpose: test lazy evaluation using squares
// To test main use: java -cs squares

import polya.*;
import java.io.*;

// Examples of creating incremental Polylists

// squares does not reuse the Growable, although it could in principal

class squares extends Growable
  {
  long n;
  squares(long n)
    {
    this.n = n;
    }

  public Object grow()
    {
    return Polylist.cons(new Long(n*n), new Incremental(new squares(n+1)));
    }

  static public void main(String []arg)
    {
    Polylist sqs = new Incremental(new squares(0));
    System.out.println(sqs);
    System.out.println(sqs.prefix(10));
    System.out.println(sqs);
    System.out.println(sqs.prefix(20));
    System.out.println(sqs);
    }
  }