Hi Alex, one more note: On Wed, Sep 20, 2017 at 1:23 AM, Alex <[email protected]> wrote:
> > If OpenCog knowledge base (AtomSpace) is the big Scheme program then we > can consider also the self-modification of this program. > Yes. Let me try to be very clear about this: atomese is designed from the ground-up to be self-modifying. This is why/how atomese differs from any other programming language. Most programming languages are designed to be used by humans: java, lisp, haskel, python, whatever. It is very hard - basically impossible - for a java program to understand itself, to change itself. atomese is designed to be used by algorithms. There are other languages that do this, but you probably have never heard of them: gimple, gil, the llvm IL, and so on. These languages, although they are designed to be modified/modifying, they are unfortunately very special: they are designed to be internal to compilers (gimple and gil for gcc, the llvm il for clang). They are not general-purpose. atomese is designed to be like gimple or gil or llvm, but general purpose There are languages designed to modify other languages: these are the "macro languages", for example: m4, cpp (the c pre-processor), (scheme) hygenic macros, and the C++ template language. Unfortunately, these are designed to be run once and only once, Macros can only be expanded once; you cannot expand them a second time. C++ templates can only be expanded once. atomese id designed to be like a macro langauge, that you can expand over and over and over. There are languages that are designed to be macro-like, but run multiple times. These are called "rule engines". Examples include DROOLS and CLIPS. However, these distinguish between the language the rules are written in, and the language that is used to represent data (the "knowledge representation" or KR language). atomese is designed so that both the rule language, and the KR language is the same language. Thus, in principle, rules can modify rules. In order to be self-modifying, one has to be able to "introspect" or examine the structure of relationships. There are languages that can examine the structure of relationships; but these again keep data distinct from the relational structure. The most famous relational language is SQL. However, SQL can only query relations on tables; it cannot apply the relational algebra on itself (except in certain very limited cases). In SQL, the KR are tables and databases, and queires are queries, they are two different things. atomese is designed to provide a relational algebra, but it can be applied to itself. Both the data (the tables/databases, the KR) are written in atomese, and the query language is also in atomese. One last example: there are graph databases; Matt Chapman mentioned one. However, (I'm not quite sure) I suspect the graph query language is not itself a graph. atomese is a graph database, and the query language is itself a graph (that can be stored in the database). These are all the different ways in which atomese has been designed to be self-modifying. The goal is to steal the very best ideas from other languages, and make them work in atomese. I think that atomese is partly successful in doing this, but I know that I am still learning new tricks, and understanding new things. We are not done yet. --linas -- *"The problem is not that artificial intelligence will get too smart and take over the world," computer scientist Pedro Domingos writes, "the problem is that it's too stupid and already has." * -- You received this message because you are subscribed to the Google Groups "opencog" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/opencog. To view this discussion on the web visit https://groups.google.com/d/msgid/opencog/CAHrUA37%3DVM%3DLn%3DC87XnDPzY_zdcWm5X4Sd1OfOSz_mZrNQXa4Q%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
