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tiny-prolog

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  2. 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:
- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above
copyright notice, this list of conditions and the following
disclaimer in the documentation and/or other materials provided
with the distribution.
- 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.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND THE
CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR THE
CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.