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!)
(begin (! (man socrates)) (:- (mortal ?x) (man ?x)) (query '(mortal ?who))) ==> (((who . socrates)))
- 2.0 ? returns list of frames; test script uses assert
- 1.0 Initial Release
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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