# Flapjax

> programming language built atop JavaScript

**Wikidata**: [Q5457453](https://www.wikidata.org/wiki/Q5457453)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Flapjax)  
**Source**: https://4ort.xyz/entity/flapjax

## Summary
Flapjax is a functional reactive programming language built atop JavaScript. It is designed to simplify the development of interactive web applications by adopting a reactive paradigm, utilizing both dynamic and duck typing disciplines. The language is open-source, released under the 3-clause BSD License.

## Key Facts
- **Classification:** Flapjax is an instance of a programming language and a functional reactive programming language.
- **Platform:** It is built atop JavaScript.
- **Typing Discipline:** The language utilizes dynamic typing and duck typing.
- **License:** Flapjax is distributed under the 3-clause BSD License.
- **Latest Version:** Version 2.1 is marked as the preferred release, published on December 15, 2009.
- **Previous Version:** Version 2.0.1 was released on May 12, 2009.
- **Official Website:** http://www.flapjax-lang.org/
- **Source Repository:** https://github.com/brownplt/flapjax
- **Copyright Status:** The software is copyrighted.

## FAQs
### Q: What programming paradigm does Flapjax use?
A: Flapjax uses the functional reactive programming (FRP) paradigm. It is built as a language layer atop JavaScript to handle events and data flow reactively.

### Q: Is Flapjax free to use?
A: Yes, Flapjax is available under the 3-clause BSD License. This permissive license allows for reuse and modification with few restrictions.

### Q: What type system does Flapjax employ?
A: Flapjax employs a typing discipline characterized as both dynamic typing and duck typing.

## Why It Matters
Flapjax matters in the landscape of web development as an early implementation of Functional Reactive Programming (FRP) tailored for the browser environment. By being built atop JavaScript, it serves as a bridge for developers to utilize reactive concepts without abandoning the web's native ecosystem. It addresses the complexity of handling asynchronous events and user interactions—a common challenge in client-side web programming—by treating events as streams of values that change over time.

Its significance lies in its approach to making web interfaces more responsive and easier to reason about compared to traditional imperative JavaScript. While many modern frameworks have since adopted reactive principles, Flapjax represents a focused effort to integrate these directly into the language design. The project provides a distinct syntax and semantics that compile to JavaScript, offering a specialized tool for creating dynamic, data-driven applications. Its release under a permissive BSD license also encourages academic and experimental adoption, contributing to the broader discourse on language design for the web.

## Notable For
- **Native FRP Implementation:** Distinct for being a dedicated functional reactive programming language rather than just a library.
- **JavaScript Integration:** Notable for being built directly "atop JavaScript," ensuring compatibility with existing web standards.
- **Duck Typing:** Employs a flexible duck typing discipline alongside dynamic typing.
- **Academic Roots:** Associated with Brown PLT (based on repository URLs), indicating a research-driven development approach.
- **Semantic Versioning:** Maintains a clear release history with specific timestamps, such as the preferred Version 2.1.

## Body
### Architecture and Design
Flapjax is constructed as a programming language layer that sits on top of JavaScript. Its primary classification is that of a **functional reactive programming language**. This architectural choice allows developers to express reactive data flows and event handling mechanisms natively. The language enforces a **typing discipline** of dynamic typing and duck typing, offering flexibility typical of scripting languages while adhering to the structural constraints of its JavaScript foundation.

### Licensing and Availability
The project is fully open-source, distributed under the **3-clause BSD License**. This ensures that the software is free to use, modify, and distribute, provided the license terms are met. The copyright status is explicitly listed as copyrighted.

### Release History
The development of Flapjax is documented through its release versions found in its source repository:
- **Version 2.0.1:** Released on May 12, 2009.
- **Version 2.1:** Released on December 15, 2009. This version is marked as the "preferred" version in the knowledge base.

### Resources and Identifiers
- **Official Website:** The primary portal for the language is located at http://www.flapjax-lang.org/.
- **Source Code:** The codebase is hosted on GitHub at https://github.com/brownplt/flapjax.
- **Identifiers:** The language is indexed in Wikipedia under the title "Flapjax" and has a Freebase ID of /m/0262dkz. It is accessible in multiple Wikipedia languages including English (en), Finnish (fi), Chinese (zh), and Cantonese (zh_yue).

## References

1. [Release 2.0.1. 2009](https://github.com/brownplt/flapjax/releases/tag/flapjax-2.0.1)
2. [Release 2.1. 2009](https://github.com/brownplt/flapjax/releases/tag/Flapjax-2.1)