https://github.com/brandonbloom/factjor

A Factor-inspired, concatenative DSL for Clojure
https://github.com/brandonbloom/factjor

Last synced: 2 months ago
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A Factor-inspired, concatenative DSL for Clojure

• Host: GitHub
• URL: https://github.com/brandonbloom/factjor
• Owner: brandonbloom
• Created: 2013-01-02T01:53:47.000Z (about 12 years ago)
• Default Branch: master
• Last Pushed: 2013-07-28T03:55:14.000Z (over 11 years ago)
• Last Synced: 2024-10-19T05:48:44.268Z (3 months ago)
• Language: Clojure
• Size: 180 KB
• Stars: 97
• Watchers: 10
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# factjor

A Clojure library inspired by [Factor](http://www.factorcode.org)

The name "Factjor" is a mashup of "Factor" and "Clojure".

It is pronounced "Fact-sure".

## Motivation

Stack languages have several very nice properties:

1. Concatenation is function composition.

2. Side effects occur from left to right.

3. Complex pipelines can be constructed without naming values ("Point Free").

These properties enable traditionally side-effectual code to be converted into

a pure function which returns a (potentially lazy) sequence of words comprising

a concatenative program. Additionally, the linear nature of execution makes

concatenative languages a natural fit for streaming protocols.

See also: [Why Concatenative Programming Matters](http://evincarofautumn.blogspot.com/2012/02/why-concatenative-programming-matters.html).

## Usage

```clojure

(require '[factjor.core :as cat :refer (defword)])

;; Math is a terrible fit for concatenative languages, but it's easy to try.

;; The run function executes a queue of words and returns the stack after

;; execution. The stack is a normal Clojure list, whose head is the stack top.

(cat/run 10 7 cat/-) ;=> (3)

;; You can define new words in terms of other words.

;; What looks like an argument list is actually just documentation.

;; It describes the "stack effect" of the word.

;; Sadly, 'cat// must be 'cat/div because of a Clojure reader bug.

(defword avg2 [x y -- avg] cat/+ 2 cat/div)

(cat/run 10 20 avg2) ;=> (15)

;; Sequences of words, called "quotations", enable higher-order words,

;; called "combinators". Use cat/call to invoke a quotation.

(cat/run 5 [2 cat/+] cat/call) ;=> (7)

(cat/run 5 10 [2 cat/+] cat/dip) ;=> (10 7)

;; Word objects can be applied early to curry values to the right:

(cat/run 5 (cat/- 2)) ;=> 3

```

This project is just an experiment, so docs will remain thin.

The experiment continues with [DomScript](https://github.com/brandonbloom/domscript),

a concatenative library with jQuery-style API. I'll have Lots

more to say about concatenative programming in the future, stay tuned.

## License

Copyright © 2013 Brandon Bloom

Distributed under the Eclipse Public License, the same as Clojure.