code: private Object executeAnd(PageContext pc, SQL sql, Query qr, Operation2 expression, int row) throws PageException {
  	// print.out("("+expression.getLeft().toString(true)+" AND
  	// "+expression.getRight().toString(true)+")");
  	boolean rtn = Caster.toBooleanValue(executeExp(pc, sql, qr, expression.getLeft(), row));
  	if (!rtn) return Boolean.FALSE;
  	return Caster.toBoolean(executeExp(pc, sql, qr, expression.getRight(), row));
      }
docs: /*
  *
  
  @param expression / private void print(ZExpression expression) {
  print.ln("Operator:"+expression.getOperator().toLowerCase()); int len=expression.nbOperands();
  for(int i=0;i<len;i++) { print.ln("	["+i+"]=	"+expression.getOperand(i)); } }/*
  
  
  
  /**
  
  execute a and operation
  
  @param qr QueryResult to execute on it
  
  @param expression
  
  @param row row of resultset to execute
  
  @return
  
  @throws PageException