HyperCom: HC 2.0 Networking

By Dave Kelly, MacTutor Editorial Board

HyperCom™: HyperCard 2.0 Network

Communications the easy way!

HyperCard has invaded the AppleTalk network with HyperCom™ 2.0 from GAVA Corporation. HyperCom is so easy to use that it seems like a natural part of HyperTalk. In fact, HyperCom is a set of extendable XCMDs and XFCNs that take care of all the details of network communications. All that’s left for you is to develop your own HyperTalk scripts to create network software for nearly any purpose.

The best thing about HyperCom is how much fun you can have with it. Programming with HyperCom is not a drudgery; it doesn’t leave you with hours trying to figure how to get it to work. It’s simplicity is the key. There is only one XCMD that is used to communicate with other HyperCom users over AppleTalk.

HyperCard 2.0’s ability to open multiple windows at the same time makes it possible to use HyperCom’s XCMDs and XFCNs without moving them to your stack. You can set up your stack to include the HyperCom stack in the current inheritance path by using the HyperTalk command:

start using stack HyperCom

This statement allows you to access handlers in the HyperCom stack without having to modify your Home stack or your copy of HyperCard.

HyperCom has one command, “Tell”. “Tell” has three special forms that can be used to find the names of other registered HyperCom users. 1) tell who puts a delimited list of all HyperCom users on the network into “the result”. Your scripts can evaluate the list in “the result” to decide who you want to send your message to. 2) tell whom shows a pop-up menu with all the HyperCom users listed. It returns the selected user name in “the result”. 3) tell whol brings up a dialog box with a list of all HyperCom users on the network. One or more users may be selected and returned in “the result”.

Once you know who you will be sending the message to, you use “Tell” and the name (or names) of the users and send your message or messages. In my example, I use tell whol to ask for a network user.

 tell whol,,”Set clock of which Mac:”

Then I use the following lines to tell the user to execute the XCMD “SetTimeDate” installed in the user’s stack.

--1

 put the result into them
 put the seconds into standardtime
 tell them, “SetTimeDate”, standardtime

The purpose of my example is to use HyperCom communications to synchronize the clock on every computer on the network with a single computer. Since HyperCard doesn’t have a command to set the clock, I made one. The Pascal source code is included at the end of this column. After the XCMD is compiled and installed into a stack, clicking on a single button brings up the user list to select which users’ clock you want to set. Then the script gets the time from the HyperTalk seconds function and sends it to the user with the command to use the SetTimeDate XCMD to set the clock.

Each copy of HyperCom is serialized and set up for a specific number of users. The basic HyperCom package supports 2 users, but there is technically no limit on the number of users. HyperCom has been used at sites with as many as 600 users over several zones. Some schools have 40-50 users on a single zone. HyperCom does not get slowed down with more users. Yet, it makes sense that if the implementation uses a single server, where the server seeks information and sends it back to the requesting station, that the speed would be affected. Of course, then, the speed is dependent on how long it takes to process each query. Database types of applications with 10-20 users are not uncommon. HyperCom does queue up messages, and allows long scripts to execute new messages to be executed by calling “Tell” in the body of the handler. Because the limitation with HyperCom is not with the network traffic, speed problems can be solved by distributing the data or processing on several machines, or using faster processors.

GAVA also provides other XCMDs and XFCNs that can be used to extend the capabilities of HyperCom. These are very useful efficiency savers. For example, with the sendResource XCMD, the SetTimeDate XCMD could be sent to the user, used to set the clock, then deleted when done. I don’t have the sendResource XCMD so I couldn’t try it. The sendFileXCMD sends files over the network. The sendSound XCMD sends a sound to be played by the receiving machine. Other commands include sendCard, sendClipboard, sendScreen and the question XFCN to evaluate expressions on a remote Macintosh.

The manual for HyperCom is brief (29 pages) and get right to the point, but since the commands are simple not much explanation is required. It does a good job in telling what the tell command does, but it leaves out a few minor details. For example, it didn’t say what to expect if the user didn’t select any users, but used the cancel button instead. Since HyperCom is simple to use, these omissions can be figured out without too much trouble.

There are some sample stacks included with HyperCom. On of the examples is a network checkers game. My son really loved that one. The examples were designed to give you some ideas of what HyperCom can do.

HyperCom is ideally suited for anyone that needs network communication capability in HyperCard. Happy Networking!

HyperCom™ is available from:

GAVA Corporation

1001 4th Ave Plaza, Suite 3200

Seattle, WA. 98154

Phone: 800-767-0647 or 206-223-4282

FAX 206-223-0653

AppleLink GAVA

InterNet: GAVA@applelink.apple.com

CompuServe: 76174,221

GENIE: GAVA

Prices:

HyperCom 2.0 (for 2 users) $99.95

HyperCom 2.0 with HyperCard 2.0 $129.95

Additional license for HyperCom $50.00

Zone license for HyperCom $499.95

sendFile XCMD $35.00, sendSound XCMD $35.00

sendCard XCMD $35.00, sendClipboard $35.00

sendScreen XCMD $35.00, question XFCN $35.00

sendResource XCMD $35.00

Requires: a Macintosh computer with System 6.0.5 or newer, 1MB RAM and a hard disk.

SOFTWARE UPDATES

Be sure to check for upgrades to your applications. Many of these are already available on AppleLink, America On-Line and other services. Some of the new versions which have been available for some time now are: Now Utilities version 2.0.3, Suitcase II version 1.2.9, and QUED/M 2.09.

{ HyperCard SetTimeDate XCMD}
{ by Dave Kelly                    }
unit SetTimeDateUnit;
{ This project handles the SetTimeDate command }
interface
 uses
{include the HyperCard interfaces in the XFCN/CMD}
 HyperXCmd;
 procedure main (paramPtr: XCmdPtr);
{ the entry point for the XCMD/XFCN }
implementation
 procedure main;
 procedure Fail (errMsg: Str255);
{ return a given error message to HyperCard }
 begin
 paramPtr^.returnValue := PasToZero(paramPtr, errMsg);
 {Set return value of the paramBlock to given message. }
 exit(main); {exit the routine }
 end;
 procedure Setthetime (paramPtr: XCmdPtr);
 var
 str: str255;
 TheTimeDate: longint;
 Error: OSErr;
 begin
 if (paramPtr^.paramCount <> 1) then
 Fail(‘%bad parameters’);
 ZeroToPas(paramPtr, paramPtr^.params[1]^, str);
{ convert the location to a string }
 TheTimeDate := StrToNum(paramPtr, str);
 { and thence to a longint }
 Error := SetDateTime(TheTimeDate);
 { if the handle is empty, then return an error}
 if Error <> noErr then
 Fail(‘DateTime not changed!’);
 end;
 begin
 Setthetime(paramPtr);
{entry point; call the Setthetime routine}
 end;
end.

STACK SCRIPT:
-- This product is for licensed HyperCom™ users only
on openstack
  global userchecktime
  start using stack HyperCom
  tell who
  put the result into card field “HyperCom Users”
  put the seconds into userchecktime
  pass openstack
end openstack
on startstack
  global userchecktime
  start using stack HyperCom
  tell who
  put the result into card field “HyperCom Users”
  put the seconds into userchecktime
  pass startstack
end startstack
on idle
  global userchecktime
  put (the seconds - userchecktime) into elapsedtime
  if (elapsedtime>=15) then
    tell who
    put the result into card field “HyperCom Users”
    put the seconds into userchecktime
  end if
  put the long time into card field “Time”
  put the long date into card field “Date”
  pass idle
end idle

CARD BUTTON:
on mouseup
  tell whol,,”Set clock of which Mac:”
  if the first line of the result is empty then exit mouseup
  put the result into them
  put the seconds into standardtime
  tell them, “SetTimeDate”, standardtime
end mouseup