tiny-prolog
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)))Repository
This egg is hosted on the CHICKEN Subversion repository:
https://anonymous@code.call-cc.org/svn/chicken-eggs/release/5/tiny-prolog
If you want to check out the source code repository of this egg and you are not familiar with Subversion, see this page.
Version History
- 2.0 ? returns list of frames; test script uses assert
- 1.0 Initial Release
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.