SUsusam·Aug 23, 2024Submission
CFRS[] Community Demos: Minimal Turtle Graphics with Only 6 Simple Commands
1 points · Open discussionsusam
cfrs
HTML2023–2024
susam / cfrs
cfrs
An extremely minimal drawing language consisting of only 6 simple commands: C, F, R, S, [, and ].
2Distinct people
11Mentions
0Explicit recommenders
261GitHub stars
What to know before exploring
What it is
An extremely minimal drawing language consisting of only 6 simple commands: C, F, R, S, [, and ].
GitHub
Where it is used
No documented product use has been verified yet.
What people are saying
No recommendation phrase was found in the indexed comments.
No classified warning is attached to this page. Read the discussions before treating silence as approval.
Also in these discussions
No other repository is repeatedly linked in the same discussions.
This week on Hacker News
Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.
No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.
Mentions over time
HN mentions by month11 dated mentions
Observed mentions: 2023-10-18 22:29:16 UTC to 2024-08-23 07:41:20 UTC.
Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.
View mention counts and date ranges
| Period | Start (UTC) | End (exclusive, UTC) | Mentions | Submissions | Comments |
|---|---|---|---|---|---|
| Oct 2023 | 2023-10-01 00:00:00 UTC | 2023-11-01 00:00:00 UTC | 6 | 3 | 3 |
| Nov 2023 | 2023-11-01 00:00:00 UTC | 2023-12-01 00:00:00 UTC | 0 | 0 | 0 |
| Dec 2023 | 2023-12-01 00:00:00 UTC | 2024-01-01 00:00:00 UTC | 1 | 1 | 0 |
| Jan 2024 | 2024-01-01 00:00:00 UTC | 2024-02-01 00:00:00 UTC | 0 | 0 | 0 |
| Feb 2024 | 2024-02-01 00:00:00 UTC | 2024-03-01 00:00:00 UTC | 0 | 0 | 0 |
| Mar 2024 | 2024-03-01 00:00:00 UTC | 2024-04-01 00:00:00 UTC | 1 | 1 | 0 |
| Apr 2024 | 2024-04-01 00:00:00 UTC | 2024-05-01 00:00:00 UTC | 1 | 0 | 1 |
| May 2024 | 2024-05-01 00:00:00 UTC | 2024-06-01 00:00:00 UTC | 1 | 1 | 0 |
| Jun 2024 | 2024-06-01 00:00:00 UTC | 2024-07-01 00:00:00 UTC | 0 | 0 | 0 |
| Jul 2024 | 2024-07-01 00:00:00 UTC | 2024-08-01 00:00:00 UTC | 0 | 0 | 0 |
| Aug 2024 | 2024-08-01 00:00:00 UTC | 2024-09-01 00:00:00 UTC | 1 | 1 | 0 |
What Hacker News says
11 sourcesThanks again for the response and the suggestions. I have updated the documentation now to incorporate the suggestions: <https://github.com/susam/cfrs/commit/f6b591b>.
In Show HN: Turtle graphics with only 6 commands: C, F, R, S, [, ]Show HN: Turtle graphics with only 6 commands: C, F, R, S, [, ]
2 points · Open discussionShow HN: CFRS[] – Minimalist turtle graphics with 6 commands: C, F, R, S, [, ]
5 points · Open discussionThanks! Glad you like it. The sibling comment by majewsky is spot on. There is not much parsing going on. Every character is read one at a time and the turtle's state is changed. Indeed the "[" and "]" commands are implemented with a stack.
The entire implementation is a single HTML page written in plain HTML + JavaScript. The evaluation of the code happens here: <https://github.com/susam/cfr/blob/0.2.0/cfr.html#L204>.
In Show HN: CFR[]: Very minimal drawing language with 5 commands: C, F, R, [, ]> The syntax definitions on github are ...
Are you referring to the short list at the top of the README on GitHub? That list does not provide "syntax definitions". That's just a quick introduction about what is about to come.
The commands are explained in detail in the section "Commands" later here: https://github.com/susam/cfr#commands
> F (fill/forward): draw a pixel and move forward
The command "F" does not draw a pixel and move forward. Instead "F" moves forward first and then draws a cell.
> [ ... ] (loop): anything inside this is executed twice
The control flow command "[" can be written without a corresponding "]". For example "[", "[F", "[[F", etc. are valid CFR[] inputs. Again, the section of the README I have linked to above defines what "[" and what "]" are.
In Show HN: CFR[]: Very minimal drawing language with 5 commands: C, F, R, [, ]CFR[] is a very minimal drawing language with 5 simple commands: C, F, R, [, ]
43 points · Open discussionAn extremely minimal drawing language consisting of only 5 simple commands
5 points · Open discussionThis is very timely because I completed writing a useless software just a few minutes ago:
CFR Brackets: https://susam.net/cfr.html
Demo: https://susam.net/cfr.html#3
Source: https://github.com/susam/cfr
It is a very minimal drawing language that supports only 5 commands: C (change colour), F (move forward), R (rotate), [ (begin block), and ] (repeat block). The commands are slightly inspired by the Logo programming language. The minimal nature is inspired by P′′. However, unlike both, this is not Turing complete.
No practical usage is intended. I wrote it for fun and I am hoping to have some more fun with it trying to draw interesting shapes using it while keeping the input code as small as possible.
“I think that it's extraordinarily important that we in computer science keep fun in computing.” -- Alan J. Perlis
In Write more "useless" software