Aug 2, 2022Learning Pilog — 7: Cuts and NegationsWelcome to the last part of the Prolog Crash Course. Today we will talk about Cuts and Negations. This post is based on this tutorial. What is a “Cut”? In the previous posts, we saw several examples of Prolog’s backtracking behaviour. In some examples, we needed a lot of steps to travel the whole…Picolisp3 min readPicolisp3 min read
Jul 17, 2022Learning Pilog — 6: More ListsIn the last post, we showed how lists look like and discussed recursion concepts and the member predicate. Today we will look into some further list functions: appending and reversing, and the concept of accumulators. This post is based on this tutorial. The append predicate Another built-in predicate in Pilog is the “append”…Picolisp4 min readPicolisp4 min read
Jul 14, 2022Learning Pilog — 5: ListsToday we will talk about an important data structure which is often used in Pilog programming: Lists. This post is based on this tutorial. What is a list in Pilog? Basically, it’s the same like in PicoLisp: A sequence of elements. Here are some examples: (John Vincent Jules Yolanda) (John (robber Honey_Bunny) @X 2 John) () ( ()…Picolisp4 min readPicolisp4 min read
Jun 13, 2022Learning Pilog — 4: RecursionIn the last post, we discussed briefly the backtracking search algorithm. Let’s explore this topic a little further as it’s an important concept in Pilog programming. This post is based on this tutorial. A recursive example Let’s illustrate the concept of recursion on a little silly example. Let’s say we define two rules…Picolisp5 min readPicolisp5 min read
Jun 9, 2022Learning Pilog -3: Unification and Proof SearchIn the last post, we have seen how we can create a knowledge base and run queries on it. Today we will try to understand how Prolog computes the result of a query. This chapter is based on this Prolog tutorial. What is Unification? Let’s check the definition for unification: Two terms unify…Picolisp4 min readPicolisp4 min read
Jun 6, 2022Learning Pilog — 2: Facts, Rules, QueriesThis post follows the tutorial from “Learn Prolog Now!”, Chapter 1. The goal of this post is to introduce the basic concept and syntax of Pilog and to write some first small programs. The Knowledge Base In imperative programming, the programmer literally tells the computer what to do step by step. In logical…Functional Programming4 min readFunctional Programming4 min read
May 30, 2022Learning Pilog — 1: A Short Introduction to PrologBefore we actually start off with Pilog, I thnk it will be good to take a few minutes to talk about Prolog, which is the basis of Pilog. A brief history of PROLOG The Prolog programming language appeared in 1972. It was developed and implemented in Marseille, France, by Alain Colmerauer and Philippe Roussel, in…Picolisp3 min readPicolisp3 min read
May 25, 2022Logical Programming in PicoLisp: Learning Pilog!Welcome to the “Programming in Pilog” series! I guess it’s quite likely that you have never heard of Pilog before. Short definition: By using Pilog, we can do logical programming within PicoLisp. In this post, we will explain what logical programming actually is and where it is used within the…Picolisp4 min readPicolisp4 min read
May 13, 2022How to hack into the PicoLisp Database (and how to prevent it!)An introduction to Cross-Site Scripting Attacks Today we will discuss some basic security aspects of database user interfaces. The principles are not at all restricted to PicoLisp, it’s a general (and quite wide-spread) vulnerability: Cross-Site Scripting. What are Cross-Site Scripting attacks? Cross-Site Scripting (XSS) attacks are a type of injection in which malicious script can be injected. XSS vulnerabilities take advantage…Picolisp7 min readPicolisp7 min read
May 8, 2022Creating a User Interface for Data Modification, Part 2In the last post, we created a HTML page that displayed the database records in a HTML form. However, all fields of this form were disabled and read-only. Now we will see how to enable the fields, and how to search in data and add these to the table. Enabling the fields The…Picolisp4 min readPicolisp4 min read
