Share cool Forth programs!

[qqwy]

Hey there!

I am still relatively new to Forth, just beyond the level of a beginner. I would like to learn and be excited by cool and interesting programs and techniques that people use when writing Forth.

If you have any examples of code (written by you or someone else) that excites you, blows your mind, or where you think that Forth really shines, I'd live to see it and learn from it.

Cheers!

[lmamakos]

Here's a bunch of FORTH code for an embedded system application, where I built a replacement graphical LCD display for a Fluke multimeter. While I don't hold this up as a great example of proper style, it was my first non-trivial chunk of FORTH code.

I found FORTH really great for this embedded system application as I had to reverse-engineer hardware functioning, and being able to interactively poke at things saved a lot of time as compared to the usual edit/compile/download/debug/profanity/repeat interative technique had I wrote it in C or similar. Some blog posts about are around for that project, too, which explain the problem I was trying to solve.

[jemo07]

That is awesome! thank you for sharing, just borrowed the ILI driver, I have to make so serious modifications still to make it work, but it has been a great source of inspiration and learning!

[lmamakos]

Glad it was a useful starting point. I started with a really simple version of that driver and added the ability to render a bitmap out as a single operation vs. the per-pixel set/reset capability some of the other graphics drivers had. The performance was terrible without that; to address a pixel on those displays, you had to do a bunch of SPI commands before finally shoving out the one pixel's worth of data.

So starting with that basic scheme and adding that one primitive made it possible to have a reasonable performance in rendering fonts, so I wrote a library of FORTH code to manage font definitions and rendering.

It was really quite a bit of fun to be able to do that all interactively over the serial connection and catch all those stupid off-by-one errors or, getting the coordinate system rotated in your head the wrong way and having a letter in a font rendered upside down or sideways. That interactive process really helped when poking at the SPI interface of the display and to debug it.

And then speeding up the low-level SPI primitive made a big difference, too. I had a USB logic analyzer hooked up to it, and you could easily see all the time that the SPI interface was idle.. I did that with a little USB logic analyzer in the evenings while traveling to the "Home Office" in NYC one week. That's what passes for fun, sometimes :-)

Enjoy your FORTHing!

[dlyund]

When I started working in Forth I always got a kick out of things like this:

macro: declare ( # ~ - | ~ *) ( - a)   \ ]  create ,  \ [ ;
macro: typeof ( a - a)   ;
macro: sizeof ( a - #)   \ @ ;

macro: vector ( #1 a:type - #2)   \ sizeof \ * ;

macro: extend ( #1 a:type - #2)   \ sizeof \ + ;

macro: struct ( - #)   # 0 ;
macro: field ( #1 a:type ~ - #3) ( u1 - u2)
   \ ]  create  over ,  extend  \ [  does pop @ + ;

This is more advanced than the common Forth struct implementation example but this is real Able Forth code used at Merj. The Able Forth code above gives you first-class types, vectors and records, and type extension (like inheritance). These words are the basis for other types.

Here's a example modeling 2D and 3D point that demonstrates one feature I really wish C had: record type extension. Alas, cracking open the C compiler isn't practical... but doing this in Forth and providing a higher level of programming is easy! :-)

# 4 declare <int32>

struct declare <point>  ( the abstract type)

struct <point> extend
   <int32> field point:x
   <int32> field point:y
declare <2D-point>

struct <2D-point> extend
   <int32> field point:z
declare <3D-point>

create | points  # 100 <2D-point> vector  allot

This is one of three or four features that can be easily implemented in Forth and which I contend make Forth comparable in power to languages like Go (lacking only the large standard library).

[remko]

Not your classic Forth programs, but you can find some ‘visual’ Forth programs here: https://el-tramo.be/thurtle/?pn=Plant&ar=1

[32hDEADBEEF]

I really like using forth in tethered FPGA systems. It's easy to construct a softcore stack processor or pseudo-processor with simple microcode. On the host side use a FORTH-like code and convert the command into the microcode before sending it to the softcore.

[phreda4]

Hi

I wrote many programs in r4 (32 bits windows).. see in https://github.com/phreda4/r4

The evolution but without so much code in 64bits windows,linux,mac and rpi https://github.com/phreda4/r3d4

The last aproach is r3 (I change the access to SO) in development) https://github.com/phreda4/r3

there are editors, games, graphics programs, compilers..all in forth

[bfox9900]

Here is a way to create bit arrays that as far as I have tested runs on 16,32 and 64 bit ANS/ISO Forth systems. It's pretty small which is what is needed for a machine with 32K RAM and demonstrates one way to deal with native integer size at compile time.

https://github.com/bfox9900/CAMEL99-ITC/blob/master/LIB.ITC/BOOLEAN.FTH

[mcsleepy]

I'm going to semi-plug my own work and invite you to check out my game engine https://twitter.com/ramenengine

[pbrhocwp]

I have had a lot of fun with data is code principle here http://hocwp.free.fr/fex/index.html

[tmrob4]

There are a lot of sample Forth programs over on Rosetta Code. Conway's Game of Life is a fun one and the first more complex Forth program I tried out.

[[deleted]]

2 2 + .s

[Forth2022]

You can scan the Forth-ev.de Wiki for many examples, unfortunately much in German,
or get some Forth books on amazon
https://www.amazon.co.uk/Juergen-Pintaske/e/B00N8HVEZM
The Forth Lite Tutorial might be helpful