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From: timothy_hansell@oboe.cis.ohio-state.edu
Newsgroups: comp.lang.smalltalk
Subject: Re: Anyway to run a program directly from smalltalk?
Message-ID: <77422@tut.cis.ohio-state.edu>
Date: 21 Feb 90 15:52:14 GMT
References: <19566@mephisto.UUCP>
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In article <19566@mephisto.UUCP> hsu@boa.gatech.edu (Yung-Kao Hsu) writes:
>I've been working on implementing an environment which requires
>an interaction between smalltalk and prolog (on Sun workstation).
>The communication between the two is thru the use of socket which
>comes with ParcPlace System with a C program acts as an agent.
>However, the establishing of the comunication link between the
>process and Socket are extremely slow and very often freezes
>the system for about 3 minutes just for it. Furthermore, one have
>to always remember to run the agent beforehand.
>
>The problem could be greatly reduced if somehow I could build
>an object that could run a "prolog" or any other process directly
>by sending a message to it. Has anyone here known of such thing?

If you look at the Terminal object you will see that it is invoking the
c-shell and then passing through commands from the user to the shell. It
is possible to use this same connection that is used by the Terminal to
send command strings directly to the shell. I've seen it done on some
utilities that ParcPlace is working on. This would allow you to start up
your 'agent' from inside smalltalk ( by that I mean have an object actually
send the command not the user ).
	The problem with this approach is that the documentation about
how this works at that level is very slim ( at least in release 2.3. I haven't
seen the docs for 2.5 yet so I don't know what it says )
	Another possibilty, if ParcPlace has added the feature in 2.5
would be to access the unix 'system' call that runs a command. Many of the
unix calls were available in 2.3 but this particular one was either
missing or not documented. But this feature allows you to make unix system
calls directly from smalltalk.
	Yet one more way to solve the problem, would be to create a 
user-primitive that allows you to send unix commands, and then build an object
to be an interface to this user-primitive. There is a great deal of
documentation on user-primitves, and since you write them in 'C' you can 
do anything you do in C with them.

Sorry, I can't offer any direct help. I've been separated from Smalltalk for
over 6 months now ( believe me it's not easy switching back to C ) and I don't
have direct access to either a running Smalltalk or to the documentation.

>
>----
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-tim
---
Tim Hansell
hansell@cis.ohio-state.edu
P.O. Box 687 South Charleston, Ohio, 45268