[comp.sys.amiga] Clipboard support, and DDE

UH2@PSUVM.BITNET (Lee Sailer) (10/13/89)

In a demo of OS/2 a couple of days ago, I saw what looked like the next
generation of clipboard capabilities, at least in one dimension.  Forgive
me, but I am rather fuzzy on the details.

They called it Dynamic Data Exchange.  In the demo, a block of numbers
in a spreadsheet was marked, and then the DDE menu option allowed that
block to be given a name, say 'SALES'.   Then, a bar chart drawing utility
from another vendor was run, and the DDE menu option allowed the user
to select from a number of currently open DDE objects, including SALES.
A bar chart of the numbers in SALES appeared.

So far, this seems pretty clipboard like (and I don't know how many
of the capabilities of IFF are there).  The difference was that when
the user goes backt to the spreadsheet, and changes some of the numbers,
the bar chart changes, too, without even a 'redraw' command from the
user.

I suppose this can be hacked using REXX and IFF, and so on, but it
looked pretty elegant to me.  Did Microsoft sream this up, or is it
something they borrowed from somewhere else?

                                            lee

bradch@microsoft.UUCP (Bradford Christian ms1) (10/22/89)

In article <89286.094909UH2@PSUVM.BITNET> UH2@PSUVM.BITNET (Lee Sailer) writes:
>In a demo of OS/2 a couple of days ago, I saw what looked like the next
>generation of clipboard capabilities, at least in one dimension.  Forgive
>me, but I am rather fuzzy on the details.
>
>They called it Dynamic Data Exchange.  In the demo, a block of numbers
>in a spreadsheet was marked, and then the DDE menu option allowed that
>block to be given a name, say 'SALES'.   Then, a bar chart drawing utility
>from another vendor was run, and the DDE menu option allowed the user
>to select from a number of currently open DDE objects, including SALES.
>A bar chart of the numbers in SALES appeared.
>
>So far, this seems pretty clipboard like (and I don't know how many
>of the capabilities of IFF are there).  The difference was that when
>the user goes backt to the spreadsheet, and changes some of the numbers,
>the bar chart changes, too, without even a 'redraw' command from the
>user.
>
>I suppose this can be hacked using REXX and IFF, and so on, but it
>looked pretty elegant to me.  Did Microsoft sream this up, or is it
>something they borrowed from somewhere else?
>
>                                            lee

I think "hot-links" have been around for a few years on "larger" computers,
but I'm not sure.  It's really very simple to do, and in fact I don't think
Microsoft had to change any code in Windows to get DDE to work.  It is simply
a small set of messages that applications can use to comunicate changes to
other apps.  The user sees the link creation as just a special form of Paste.
Basicaly, the user copies something from one app to the clipboard and then
issues a Paste Link command in the other app.  The second app informs the
first that it wants to link to the source of the data in the clipboard.  The
first app remembers what apps have linked to it's data and sends messages 
whenever relevent things change.  The interesting messages are:

	Initiate(application, topic)
	Terminate()
	Request(format, item)
	Data(pointer, item)
	Advise(options, item)
	Unadvide(item)
	Poke(pointer, item)

Initiate starts a conversation between two applications and Terminate stops
it.  Request is sent by a client to ask the server to provide an item.  Data
is the server's response (pointer points to the actual object being sent).
Advise sets up a connection to a particular object (Initiate just connects
the apps) and Unadvise breaks the connection.  Poke is use be servers to
send data to a client without a link being set up.

Anyway, DDE can be fun (and useful :-) and would be realy easy to get going
on the Amiga.  All it would take would be for Commodore to spec it.

So, is it "in there?"

	BradCh