# Prolog

> programming language that uses first order logic

**Wikidata**: [Q163468](https://www.wikidata.org/wiki/Q163468)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Prolog)  
**Source**: https://4ort.xyz/entity/prolog

## Summary
Prolog is a programming language that uses first-order logic to solve problems by defining rules and facts rather than step-by-step instructions. It was developed in 1972 by Alain Colmerauer, Robert Kowalski, and Philippe Roussel, making it a foundational language in logic programming.

## Key Facts
- **Inception**: 1972
- **Designed by**: Alain Colmerauer, Robert Kowalski, and Philippe Roussel
- **Paradigm**: Logic programming, declarative programming
- **Instance of**: Programming language, declarative programming language, deductive language, logic programming language
- **File extensions**: .pl, .pro, .P
- **Influenced by**: Planner (1969)
- **Competes with**: Lisp (1958), Logo (1967)
- **Aliases**: Programming in Logic, ISO 13211-1, PROgrammation en LOgique, etc.
- **Derivative works**: Strawberry Prolog, Datalog

## FAQs
### Q: What is Prolog used for?
A: Prolog is primarily used for logic programming, where it defines rules and facts to solve problems rather than following step-by-step instructions. It is often used in artificial intelligence, expert systems, and natural language processing.

### Q: Who created Prolog?
A: Prolog was created by Alain Colmerauer, Robert Kowalski, and Philippe Roussel in 1972.

### Q: How does Prolog differ from other programming languages?
A: Unlike imperative languages that use step-by-step instructions, Prolog uses declarative logic to define relationships and rules. It is particularly suited for symbolic reasoning and problem-solving tasks.

### Q: What are some notable applications of Prolog?
A: Prolog has been used in expert systems, natural language processing, and artificial intelligence research. It remains relevant in academic and specialized applications where logic-based reasoning is required.

### Q: Is Prolog still used today?
A: Yes, Prolog is still used in niche applications, particularly in fields requiring symbolic reasoning and logic-based problem-solving, though it has declined in mainstream use compared to other languages.

## Why It Matters
Prolog was a groundbreaking language in the field of logic programming, introducing a declarative approach to problem-solving that contrasts with the imperative methods of languages like C or Java. Its development in 1972 marked a significant shift in how computers could reason and solve problems using formal logic. Prolog's influence is evident in later languages like Datalog and has been applied in areas such as artificial intelligence, expert systems, and natural language processing. While it has not achieved the same widespread adoption as general-purpose languages, Prolog remains a valuable tool for specialized applications where logic-based reasoning is essential. Its legacy continues to inspire research in symbolic computation and automated reasoning.

## Notable For
- **Foundational in logic programming**: Prolog was one of the first languages to implement the logic programming paradigm, influencing later languages like Datalog.
- **Declarative approach**: Unlike imperative languages, Prolog allows programmers to define what needs to be achieved rather than how to achieve it.
- **Expert systems**: Prolog was widely used in early expert systems, demonstrating its capability in symbolic reasoning.
- **Academic influence**: Prolog remains a key language in computer science education, particularly in courses on logic and artificial intelligence.
- **Standardization**: Prolog has been standardized under ISO/IEC 13211-1, ensuring consistency in its implementation across different platforms.

## Body
### Origins and Development
Prolog was developed in 1972 by Alain Colmerauer, Robert Kowalski, and Philippe Roussel. It emerged from research in artificial intelligence and logic programming, building on earlier work in symbolic reasoning and automated theorem proving. The language was designed to allow programmers to express problems in terms of logical relationships rather than procedural steps.

### Programming Paradigm
Prolog is a declarative programming language that follows the logic programming paradigm. It uses first-order logic to define rules and facts, allowing the system to infer solutions through logical deduction. This approach contrasts with imperative programming languages, which rely on explicit instructions for the computer to follow.

### Applications
Prolog has been applied in various domains, including:
- **Expert systems**: Early expert systems used Prolog to encode knowledge and reasoning rules.
- **Natural language processing**: Prolog's ability to handle symbolic reasoning made it suitable for parsing and generating natural language.
- **Artificial intelligence**: Prolog was used in early AI research for symbolic computation and automated reasoning.

### Standardization and Legacy
Prolog has been standardized under ISO/IEC 13211-1, ensuring compatibility and consistency across implementations. The language has influenced later developments in logic programming, including Datalog and constraint logic programming. While Prolog has not achieved the same level of mainstream adoption as general-purpose languages, it remains relevant in academic and specialized applications.

### Competitors and Alternatives
Prolog competes with other programming languages, particularly those designed for symbolic reasoning and logic-based problem-solving. Notable alternatives include:
- **Lisp**: A functional programming language based on the lambda calculus, which has influenced many modern languages.
- **Logo**: An educational programming language designed to teach computational thinking and logic to beginners.

### Derivative Works
Prolog has inspired several derivative works and related languages, including:
- **Strawberry Prolog**: A modern implementation of Prolog with additional features.
- **Datalog**: A declarative query language that builds on Prolog's logic programming principles.

## Schema Markup
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## References

1. [Source](https://github.com/JohnMarkOckerbloom/ftl/blob/master/data/wikimap)
2. Freebase Data Dumps. 2013
3. Quora
4. National Library of Israel
5. KBpedia
6. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)