tiny-prolog

  1. tiny-prolog
    1. Description
    2. Example
    3. Version History
    4. License

Description

tiny-prolog is an implementation of a tiny PROLOG interpreter that is based on an even tinier PROLOG interpreter written in MACLISP by Ken Kahn.

The prolog procedure takes a query LIST1 and a database LIST2 as arguments, attempts to prove LIST1 in LIST2, and returns the result(s).

new-database! sets up a fresh PROLOG database (thereby deleting any existing one).

fact! adds a new fact to the database.

predicate! adds a predicate with the head LIST1 and the clauses LIST2 ... to the database.

query attempts to prove LIST1. It returns a list of results. An empty list indicates that LIST1 could not be proven.

The following macros add some syntactic sugar for interactive use; they allows the user to write, for instance, (! (man socrates)) instead of (fact! '(man socrates)).

(! fact)              ==>  unspecific
(:- list1 list2 ...)  ==>  unspecific
(? query)             ==>  (list-of frame)

The following special predicates are implemented in the interpreter: (== A B) returns a new environment if A can be unified with B, else NO. (Dif A B) returns NO if A can be unified with B, else YES (use only at the end of a clause!)

Example

 (begin (! (man socrates))
        (:- (mortal ?x)
            (man ?x))
        (query '(mortal ?who)))  ==>  (((who . socrates)))

Version History

License

tiny-prolog was written by Nils M Holm and ported to Chicken by Ivan Raikov.

Copyright Nils M Holm.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
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notice, this list of conditions and the following disclaimer.
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disclaimer in the documentation and/or other materials provided
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- Neither name of the copyright holders nor the names of its
contributors may be used to endorse or promote products derived
from this software without specific prior written permission.
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