jarble’s gists

jarble / type_inference.pl

Last active January 22, 2020 19:10

A simple demo of type inference in SWI-Prolog

	:- initialization(main).
	:- set_prolog_flag('double_quotes','chars').

	main :- Term = (member(Z,A),append(A,B,C),dif(A,[true,false])),has_type(Term:Type,Types),writeln('Term with types to infer:'),writeln(Term),writeln('Types of variables in this term:'),writeln(Types).

	greater_than(A,B) :-
	A > B.

	matches_any_([],B) :- false.
	matches_any_([A\|A1],B) :-

jarble / partial_evaluator.pl

Last active September 25, 2019 00:50

A partial evaluator for non-recursive Prolog programs

	:- initialization(main).
	:- set_prolog_flag(double_quotes,chars).
	main :- recursive_partial_eval((is_between(3,4,5) -> false,is_between(1,C,3);is_between(3,4,5);is_between(3,D,4)),B),writeln(B).

	recursive_partial_eval(A,B) :-
	find_all_clauses_(A,A1),
	(A==A1,A1=B;recursive_partial_eval(A1,B)).

	find_all_clauses_(A,A) :- var(A).
	find_all_clauses_(A,B) :- nonvar(A),find_all_clauses(A,B).

jarble / adaptive_parser.py

Created August 26, 2019 02:23

A simple adaptive parser in Python

	import copy
	import sys
	import subprocess
	from tokenize import tokenize
	from io import BytesIO

	def tokenize_input(the_input):
	return ([a.string for a in list(tokenize(BytesIO(the_input.encode('utf-8')).readline)) if a.string not in ["\n","","utf-8"]])

	def matches_pattern(string,pattern):

jarble / pseudocode_parser_generator.py

Last active August 11, 2019 17:41

This Python script generates a "pseudocode parser" for the Nearley parser generator. It's based on an adaptive parsing algorithm or "adaptive grammar."

	import copy
	import sys
	import subprocess

	def matches_pattern(string,pattern):
	if len(string) != len(pattern):
	return False
	for i in range(0,len(string)):
	if is_expr_(pattern[i]):
	for j in range(0,len(string)):

jarble / type_inference.pl

Last active February 17, 2019 05:19

A simple example of type inference in Prolog using Constraint Handling Rules

	:- initialization(main).
	:- set_prolog_flag('double_quotes','chars'). ;this is for SWI-Prolog
	:- use_module(library(chr)).
	:- chr_constraint type/2.
	type(A,B) \ type(A,B) <=> true.
	type((A;B),C) ==> C = bool,type(A,bool),type(B,bool).
	type((A,B),C) ==> C = bool,type(A,bool),type(B,bool).
	type(A>B,C) ==> C = bool,type(A,number),type(B,number).
	type(A<B,C) ==> C = bool,type(A,number),type(B,number).
	type(A+B,C) ==> C = number,type(A,number),type(B,number).

jarble / prolog_translator.jison

Created January 13, 2019 09:28

A Prolog-to-Python translator using list comprehensions

	/* lexical grammar */
	%lex
	%%

	\s+ /* skip whitespace */
	[0-9]+("."[0-9]+)?\b return 'NUMBER'
	\"([^\\\"]\|\\.)*\" return 'STRING_LITERAL'
	"forall" return 'forall'
	"copy_term" return 'copy_term'
	"if" return "if"

jarble / duplicate_code_detection.pl

Last active August 21, 2021 21:17

An example of duplicate code detection in Prolog

	:- initialization(main).
	:- set_prolog_flag(double_quotes, chars).

	main :-
	duplicate_code(
	(G<A;A>B+1;C>D+1),
	Output),
	writeln(Output).

	%find a duplicated term within a term

jarble / closure_example.pl

Last active February 8, 2024 09:05

An example of closures (or "nested predicates") in Prolog

	%Since SWI-Prolog does not have a built-in implementation of closures, I wrote my own implementation here.

	:- initialization(main).
	:- set_prolog_flag('double_quotes','chars').

	main :- predicate_with_nested(1,C),writeln(C).

	call_local(Definition,Params) :-
	copy_term(Definition,(Params :- Body)),
	call(Body).

jarble / speaking_notes.html

Created December 28, 2017 05:23

	<!DOCTYPE html>
	<html>
	<body>

	<input type="text" id="input_box"/> <button id = "speak">Click me</button><br/><br/>Repeat how many times:<input type="text" id="repeat"/>

	<script type = "text/javascript">
	var speak = function(){for(var i = 0; i < document.getElementById("repeat").value; i++)
	window.speechSynthesis.speak(new SpeechSynthesisUtterance(document.getElementById('input_box').value));};

jarble / chr_metainterpreter.pl

Last active November 8, 2018 23:07

This is an attempt to write a meta-interpreter for Constraint Handling Rules.

	:- initialization(main).
	:- set_prolog_flag('double_quotes','chars').
	:- use_module(library(chr)).
	:- chr_constraint is_true/1.

	is_true(X) \ is_true(X) <=> true.
	is_true(X ==> Y),is_true(X1) ==> copy_term((X -> Y),(X2 -> Y1)),(X2=X1,(is_true(X1)->is_true(Y1));X2\=X1),writeln(Y).
	is_true((X;Y)) ==> is_true(X);is_true(Y).
	is_true((X,Y)) ==> is_true(X),is_true(Y).
	is_true(is_true(X)) ==> is_true(X).