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From: Paul E Bennett <Paul_E.Bennett@topmail.co.uk>
Newsgroups: comp.lang.forth
Subject: Re: Program or be Programmed !
Date: Fri, 19 Dec 2014 09:29:24 +0000
Organization: Hidecs Consultancy
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WJ wrote:

> Paul E Bennett wrote:
> 
>> I was displaying a sine-wave of
>> asterix characters scrolling continuously down the screen. 3 lines of
>> code generated the sine-wave (and cosine) numbers and the other 30 or so
>> lines did scaling and arrangements for its display. I was showing the
>> source code in a separate window.
> 
> Gauche Scheme:
> 
> (define line-length 79)
> (define mid-point (div line-length 2))
> (define one-line (string-append
>   (make-string mid-point #\space) "|" (make-string mid-point #\space)))
> (define (pause) (sys-nanosleep 5e7))
> (let loop ((x 0.0))
>   (when (< x 22)
>     (let ((this-line (string-copy one-line))
>           (p (round->exact (+ mid-point (* mid-point (sin x))))))
>       (string-set! this-line p #\*)
>       (print this-line)
>       (pause))
>     (loop (+ 0.1 x))))
> 
> Partial output:

[%X]

Ok, now do that without using the sin x function (which I did not in my 
example). I shall post the full source of my example shortly. I have just 
had a quick look and there is a total of 65 lines defining 7 words including 
the comments and a more vertical style than most use. You will see 
(eventually) that had I used a more horizontal style it would probably have 
been just seven lines.

The reason I started playing with the central sine-wave generation was for a 
small robotic project that required me to generate such a waveform. The 
three line sine-wave generation code is all that I am using from this 
example for the robotics project.

-- 
********************************************************************
Paul E. Bennett IEng MIET.....<email://Paul_E.Bennett@topmail.co.uk>
Forth based HIDECS Consultancy.............<http://www.hidecs.co.uk>
Mob: +44 (0)7811-639972
Tel: +44 (0)1235-510979
Going Forth Safely ..... EBA. www.electric-boat-association.org.uk..
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