picatjs - Picat and Prolog programming languages in JavaScript

Work in Progress

This is a JavaScript implementation of subset of Picat and Prolog programming languages.

What is Picat programming language?

Picat (http://picat-lang.org/) is a simple, and yet powerful, logic-based multi-paradigm programming language aimed for general-purpose applications. It was created by Neng-Fa Zhou and Jonathan Fruhman. Originally it based on B-Prolog language.

Picat is a rule-based language, in which predicates, functions, and actors are defined with pattern-matching rules. Picat incorporates many declarative language features for better productivity of software development, including explicit non-determinism, explicit unification, functions, list comprehensions, constraints, and tabling. Picat also provides imperative language constructs, such as assignments and loops, for programming everyday things.

Here is example of Picat program:

	main => println(fact(100)).

	fact(1) = 1.
	fact(N), >(N,1) = *(N,fact(-(N,1))).

Due Picat (and this JS implementation) is based on Prolog language some Prolog programs are also allowed:

	
	main(X,Y) :- son(X,Y).

	father(andrey,david).
	father(andrey,alex).
	son(X,Y) :- father(Y,X).

JavaScript implementation

	picat(<program>, <goal>, [<parameters array>], <flag></flag>);

Command line

	> picatjs <filename> [-g <goal>] [<parameters>...]

where:

• filename - file with Picat program (usually with *.pi extension)
• goal - goal
• parameters

By default Picat calls main goal.

If you define goal wit -g flag the program will call goal goal.

You can define parameters:

	> picatjs one.pi 1 2 3

The program will call the goal main(["1","2","3").

Credits

The elegant multidisciple Picat language was designed by by Neng-Fa Zhou and Jonathan Fruhman.

This JavaScript implementation is based on the article Solving riddles with Prolog and ES6 generators written by Curiosity driven.

License

This software is released under MIT License

Copyright (c) 2022 Andrey Gershun