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Comment by fogus | Hacker News Reader

I think that the story is that CLIPS was inspired by ART's rule syntax, but developed independently and without access to its source.

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I thought the developer had access to the ART software system, software written in ART and ART documentation - since that was what NASA was using already to develop rule-based expert systems?

Given that ART was written in Common Lisp and exposed a full Common Lisp inside, it would also be trivial to get large amounts of information about its implementation (data structures, functions, arglists, documentation, traces, macro expansions, disassemblies, ...). I'm pretty sure ART itself had extensive debugging&tracing tools for the rules engine.

Not having source to some Common Lisp software, says very little, when the full Common Lisp environment is available for introspection.

I wouldn't expect that ART was shipped in source to its customers. But I would expect that both ART and the underlying Lisp had excellent introspection capabilities.

http://clipsrules.sourceforge.net/WhatIsCLIPS.html

> The prototype version of CLIPS was developed in the spring of 1985 in a little over two months. Particular attention was given to making the tool compatible with expert systems under development at that time by the Artificial Intelligence Section. Thus, the syntax of CLIPS was made to very closely resemble the syntax of a subset of the ART expert system tool developed by Inference Corporation.

Since ART was what they were using.

> Although originally modelled from ART, CLIPS was developed entirely without assistance from Inference or access to the ART source code.

Sure, it wouldn't say anything else in their position.

I would point out that the vast majority of conspiracy theories fall off the stupid tree and hit every branch on the way down, but that's exactly what someone who's involved in a conspiracy would say. If you believe we had access to the ART source code or were smart enough to glean large amounts of information about its implementation, you also have to believe that we were too stupid or inept to make use of that knowledge. The crown jewels of the ART source code would have been their specific implementation of the rete algorithm and there's no way you could look at CLIPS performance at that point in time and compare it to ART and come to the conclusion that we knew anything specific about their implementation.

The points that were mentioned on the CLIPS history page were 'compatibility' and 'syntax'.

I would guess to be compatible one would need to know both syntax and semantics (what the constructs are doing and how a rule system executes the rules) of the constructs of ART. Having access to documentation and actual implementations helps with that.

I never did say anything about source code or performance. I would also not think that people were stupid - especially since they were smart enough to develop expert systems.

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