private Object executeExp(PageContext pc, SQL sql, Query qr, ZExp exp, int row) throws PageException {
	if (exp instanceof ZConstant) return executeConstant(sql, qr, (ZConstant) exp, row);
	else if (exp instanceof ZExpression) return executeExpression(pc, sql, qr, (ZExpression) exp, row);
	throw new DatabaseException("unsupported sql statement [" + exp + "]", null, sql, null);

    }
private Object executeExp ( PageContext pc , SQL sql , Query qr , ZExp exp , int row ) throws PageException { if ( exp instanceof ZConstant ) return executeConstant ( sql , qr , ( ZConstant ) exp , row ) ; else if ( exp instanceof ZExpression ) return executeExpression ( pc , sql , qr , ( ZExpression ) exp , row ) ; throw new DatabaseException ( "unsupported sql statement [" + exp + "]" , null , sql , null ) ; }
Executes a ZEXp

@param sql
@param qr Query Result
@param exp expression to execute
@param row current row of resultset
@return result
@throws PageException