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From: creedy@cca.UUCP (Christopher Reedy)
Newsgroups: net.lang.ada
Subject: Re: ForTran-Ada + flamette + questi
Message-ID: <9404@cca.UUCP>
Date: Thu, 7-Aug-86 09:26:33 EDT
Article-I.D.: cca.9404
Posted: Thu Aug  7 09:26:33 1986
Date-Received: Sat, 9-Aug-86 08:01:35 EDT
References: <8129@cca.UUCP> <4700073@ada-uts>
Reply-To: creedy@cca.UUCP (Christopher Reedy)
Organization: Computer Corp. of America, Cambridge
List-Id: <comp.lang.ada>

Since I didn't see any responses to this:
In article <4700073@ada-uts> stt@ada-uts writes:
>
>Unfortunately, passing a task doesn't do the trick
>because the task type (which must be specified) implies
>the code for the task.  Of course tasks are great for
>holding onto a bit of state, if that is your primary goal.

There was a nice talk given at the 1985 Ada Europe conference in Paris
on this issue.  The thrust of the talk was that one needs an additional
task to act as an intermediary between the invoking and the invoked
tasks.  The intermediary task makes no entry calls, simply receiving
calls from both of the other tasks.  Thus, the invoking task need not
know the type of the invoked task.  (If anyone would like to see a
simple example, I have one.  However, it takes about three pages of
listing.)

In most cases this seems like a lot of overhead to go through to make a
variable procedure call.  However, the classical asynchronous buffer is
an example of this sort of approach.  In fact, if one was to combine the
intermediary task with an asynchronous buffer or some similar mechanism,
this approach might make a great deal of sense.

Chris Reedy
Computer Corporation of America
--Standard disclaimer: All opinions are my own.--