Re: How about a Safe Virtual Machine?

Thomas Walsh (
Wed, 5 Oct 1994 09:09:10 +0100

From: Nathaniel Borenstein <>

> But I also believe that building useful Internet services involves
> significant complexity management, and that complexity management is a
> particular weakness of Tcl. Sure, the implementation of Safe-Tcl is
> clean and somewhat simple, but at the cost of complexity of programs
> built on that platform.

I think you may have missed a key point that Dave made. We undoubtedly
want very complex CSCW applications on the network. But the part of
such systems that has to be executed in a safe language is VERY limited.
In particular, you only need to use Safe-Tcl for what I call "RPC to
human beings". Most of your work can go on inside trusted servers on
the net, programmed in any language you like. The role of Safe-*
languages is much more limited -- it needs to be able to go off and
interact with the user on his/her platform, but it needn't contain the
whole application. I think you overestimate the need for very large
programs in the safe language. However, I also agree that Tcl needs
better support for modules.

In a nutshell ( and maybe not to clearly ! ) this is what I was trying to
say needed to be broken into "core" functionallity and "mobile" functionallity.

The core functionallity is always "resident" in the server and can be written
in language du jour.

The "mobile" functionallity is interpreted and bound at runtime.

Lets Identify and list these two basic components.

"The Information Superhighway At Your FingerTips"
#include <std.disclaim.h>