Prolog

Prolog is a processor for Prolog language written in Scala. It is a work in progress. ISO compliance plus support for a string type is the goal.

Examples

Family Tree

Here's an example which defines a family tree along with various types of family relationships.

female( anne ).
female( rosie ).
female( emma ).
female( olivia ).
female( mia ).

male( randy ).
male( don ).
male( liam ).
male( logan ).
male( aiden ).

parent( don, randy ).
parent( don, anne ).
parent( rosie, randy ).
parent( rosie, anne ).
parent( liam, don ).
parent( olivia, don ).
parent( liam, mia ).
parent( olivia, mia ).
parent( emma, rosie ).
parent( logan, rosie ).
parent( emma, aiden ).
parent( logan, aiden ).

relation( X, Y ) :- ancestor( A, X ), ancestor( A, Y ), X \= Y.
ancestor( X, Y ) :- parent( X, Y ) ; parent( X, P ), ancestor( P, Y ).

mother( X, Y ) :- female( X ), parent( X, Y ).
father( X, Y ) :- male( X ), parent( X, Y ).
daughter( X, Y ) :- female( X ), parent( Y, X ).
son( X, Y ) :- male( X ), parent( Y, X ).
siblings( X, Y ) :- parent( P, X ), parent( P, Y ), X \= Y.
full_siblings( A, B ) :-
  parent( F, A ), parent( F, B ),
  parent( M, A ), parent( M, B ),
  A \= B, F \= M.
sister( X, Y ) :- female( X ), siblings( Y, X ).
brother( X, Y ) :- male( X ), siblings( Y, X ).
uncle( U, N ) :- male( U ), siblings( U, P ), parent( P, N ).
aunt( A, N ) :- female( A ), siblings( A, P ), parent( P, N ).
grandparent( X, Y ) :- parent( X, P ), parent( P, Y ).
grandmother( X, Y ) :- female( X ), grandparent( X, Y ).
grandfather( X, Y ) :- male( X ), grandparent( X, Y ).

This example is contained in the repo as examples/family_tree. Run the REPL (repeat-evaluate-print-loop) and type

;l examples/family_tree

to load the example. To get a list of all the persons in the family tree who are fathers, type

father( F, _ )*

Output

F = don

F = liam

F = logan

To get the father of 'mia', type

 father( F, mia )

Output

F = liam

Library

This example program shows how to

This program prints

Executable

This next example shows how to use Prolog as an executable from the command line.

The above command prints

Usage

Library

Use the following definition to use Prolog in your Maven project:

<repository>
  <id>hyperreal</id>
  <url>https://dl.bintray.com/edadma/maven</url>
</repository>

<dependency>
  <groupId>xyz.hyperreal</groupId>
  <artifactId>prolog</artifactId>
  <version>0.2</version>
</dependency>

Add the following to your build.sbt file to use Prolog in your SBT project:

resolvers += "Hyperreal Repository" at "https://dl.bintray.com/edadma/maven"

libraryDependencies += "xyz.hyperreal" %% "prolog" % "0.2"

Executable

An executable can be downloaded from here. You do not need the Scala library for it to work because the JAR already contains all dependencies. You just need Java 8+ installed.

Run it as a normal Java executable JAR with the command java -jar prolog-0.2.jar <template> in the folder where you downloaded the file, where template is the name of the template file to be rendered.

Building

Requirements

• Java 11
• SBT 1.2.7+
• Scala 2.12.8+

Clone and Assemble Executable

git clone git://github.com/edadma/prolog.git
cd prolog
sbt assembly

The command sbt assembly also runs all the unit tests.

License

ISC © 2018 Edward A. Maxedon, Sr.