https://github.com/rachbowyer/henderson

SICP's Henderson Picture Language in Clojure
https://github.com/rachbowyer/henderson

clojure henderson-picture-language sicp

Last synced: about 1 year ago
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SICP's Henderson Picture Language in Clojure

• Host: GitHub
• URL: https://github.com/rachbowyer/henderson
• Owner: rachbowyer
• License: other
• Created: 2021-03-02T16:02:04.000Z (over 5 years ago)
• Default Branch: main
• Last Pushed: 2021-03-19T12:09:31.000Z (over 5 years ago)
• Last Synced: 2024-10-19T05:18:20.782Z (over 1 year ago)
• Topics: clojure, henderson-picture-language, sicp
• Language: Clojure
• Homepage: https://bowyer.info/sicp-henderson-picture-language
• Size: 792 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# Henderson



Henderson is a partial implementation in Clojure of the Henderson Picture Language

(HPL) described in Structure and Interpretation of Computer Programs by Harold Abelson 

and Gerald Sussman (aka [SICP](https://mitpress.mit.edu/sites/default/files/sicp/index.html)).

HPL was invented by Professor Peter Henderson and first 

described in his 1982 paper (Henderson, P. (1982) Functional Geometry. Proc. 

ACM Symp. on Lisp and Functional Programming. pp. 179-187). An updated version of

the paper is available [here](https://eprints.soton.ac.uk/257577/1/funcgeo2.pdf).

SICP uses HPL to illustrate abstraction, 

high order functions, combinators and composition.

Around 6 years ago, I was working through SICP in Clojure and arrive at Chapter

2.2.4. I was unable to render my _painters_ so set about writing an

implementation in Clojure. I always planned to pull the code out into a standalone

library, but never found the time until now!

## Installation

Henderson is available from Clojars.

[![Clojars Project](https://img.shields.io/clojars/v/rachbowyer/henderson.svg)](https://clojars.org/rachbowyer/henderson)

## Usage

To make the Henderson functions available type:

    (require '[henderson.core :as hc])

    (require '[henderson.examples :as he])

There are predefined painters _wave_, _wave2_, _wave4_ and _rogers_ as described

in SICP. The function _show-picture_ will render a painter. 

Examples (from page 133 SICP 2nd Edition)

     (hc/show-picture (hc/right-split he/wave 4) 400 400)

     (hc/show-picture (hc/corner-split he/rogers 4) 400 400)

Note that the origin is at the top left, positive x goes right

and positive y goes down in accordance with Java2d and most UI systems.

For more information see the docs in /doc and of course SICP!

## License for Henderson

Distributed under the Creative Commons Attribution-ShareAlike 4.0

International licence (["CC BY-SA 4.0"](https://creativecommons.org/licenses/by-sa/4.0/))