6 ms·

Easy Forth: Learn forth with REPL in the browser

100 points by guerrilla 6y ago

Munksgaard 6y ago
This is great! Forth is such an interesting language. Does anyone know of uses in industry?
- rwmj 6y ago
  Not sure if it counts as "industry" but FORTH-based Open Firmware is still used as a bootloader for some PowerPC machines. You can try this out under qemu: $ qemu-system-ppc64 VNC server running on ::1:5900 $ vncviewer :0 Ready! 0 > 1 2 3 * + . 7 ok 0 > WORDS (gigantic list of built-in words ...)
  - exikyut 6y ago
    And FWIW Open Firmware runs on x86 too.
- jonsen 6y ago
  Third line of the introduction: “...is still used today for certain applications.” and is clickable.
- guerrilla 6y ago
  According to Wikipedia[1] it's used in astronomy and aerospace. It's also used in OpenFirmware like in old PowerPC Mac and IBM computers. 1. https://en.m.wikipedia.org/wiki/Forth_(programming_language) https://en.m.wikipedia.org/wiki/Forth_(programming_language)
- s-macke 6y ago
  In the gaming industry. The game Starflight was written in Forth. https://en.wikipedia.org/wiki/Starflight https://en.wikipedia.org/wiki/Starflight Ok, this is an ancient example. But still :-) The source code is partially available. Here one example. https://web.archive.org/web/20030906110447/http://www.sonic.net/~sage/sf/src/SOURCE-11-05-85/BANK_CMP.pdf https://web.archive.org/web/20030906110447/http://www.sonic....
- MaxBarraclough 6y ago
  See: • https://www.forth.com/resources/who-uses-forth/ https://www.forth.com/resources/who-uses-forth/ • https://vfxforth.com/#customers https://vfxforth.com/#customers (Curiously this also turned up on another thread, https://news.ycombinator.com/item?id=26165804 https://news.ycombinator.com/item?id=26165804 )
- dastain 6y ago
  You can install it on MCUs and use it to debug code pretty easily and makes it really nice to use reflection[1]. This use is not necessarily limited to enthusiasts, since nowadays even Arduino ends up in commercial products. While the language itself it's considered difficult to read by some, it's a great way to access MCUs features in a stack-based way and at a level higher than assembly. 1. https://www.youtube.com/watch?v=dvTI3KmcZ7I https://www.youtube.com/watch?v=dvTI3KmcZ7I
- lebuffon 6y ago
  The Fedex handheld terminal was re-written in Forth... twice. :) First time all the features wouldn't fit. Forth re-write fit with room to spare. (factoring is easy in Forth) New Hardware! Everything fit but batteries didn't last a full shift. :( Forth with a proprietary tasker put the device to sleep at every opportunity. Problem solved.
  - Jtsummers 6y ago
    > factoring is easy in Forth Even more than working in functional languages like SML, Forth (and RPL, my first stack language) taught me how to factor out code and remove/minimize duplication. It's just so obvious when using it where the duplication is, the hard part is coming up with decent names. But if a sequence of words can be given a good name, give it that name and define it.
- joubert 6y ago
  Space.
- JadeNB 6y ago
  Here's an HN post on Forth in space! https://news.ycombinator.com/item?id=26164942 https://news.ycombinator.com/item?id=26164942
bmitc 6y ago
Forth is just fun.
- MaxBarraclough 6y ago
  You're still thinking in infix notation! FUN FORTH IS
  - joubert 6y ago
    Missing the tone. :-)
jonsen 6y ago
How do you press “the Enter key” on an iPad? My operators are just stacked with Return.
- exikyut 6y ago
  For reference, what does the iOS keyboard you're seeing look like? Selecting the text field in Android just pops up my selected keyboard (Gboard), which includes an Enter key.
  - jonsen 6y ago
    I use the standard keyboard. Don’t know what I can compare the look of it with. I’ve never seen or used an Android device. Maybe I can find a keyboard app with an Enter key.
ilaksh 6y ago
Check out ColorForth. Or RaonbowForth online http://rainbowforth.appspot.com/ http://rainbowforth.appspot.com/ https://youtu.be/N1FUY6g5crA https://youtu.be/N1FUY6g5crA
mikewarot 6y ago
I'm amazed that it worked so well, it did confuse me that each repl didn't know the previously defined functions, is that just me? Forth is almost the postfix inverse of lisp. Instead of arity errors, you have stack over and underflow. And it only has one list, instead of lists of lists. Oh, and it's not garbage collected Oh, it it's not homoiconic {edit]I guess it's really not the same thing at all Amazing how a day's exposure to Racket shifted my opinion
- mumblemumble 6y ago
  > Oh, it it's not homoiconic Is it as homoiconic as it needs to be? It's been a while since I've played with it in any real way, but, as I recall, Forth represents both data and code in exactly the same way: Blobs of data with no associated type information, that you're allowed to fiddle in any way you want, with no guard rails. So it seems like there's no reason you couldn't write some words for manipulating code every bit as easily as you could write some words for manipulating any other data. Lisp gives you a lot more out of the box, of course. But Lisp gives you a lot more of everything out of the box.
  - astrobe_ 6y ago
    It depends on the implementation. With Indirect Threaded Code (ITC), "functions" are represented more or less as a list of other functions or primitives to call. But there are also classic bytecode-based Forth implementations, subroutine threaded code implementation (which is a simple form of native code generation), etc. In my experience, Forth's "immediate" words, which let you execute code at compile time, combined with the availability of some (or most) of the compiler's part, let you do quite a lot of things. In other words, you don't manipulate code, you directly generate code. For instance, if your implementation does not have 1+ (silly example), you can make a word "1+" that compiles "1 +" inline (or increment the top of stack if you interpret stuff from the REPL). To answer your question, I use a dialect of Forth that has, I think, less capabilities than standard Forth in this area and rarely felt the need to implement them. At the risk of showing I am a blub programmer, I think homoiconicity is overrated - for the user (for language implementers maybe it's another story).
  - 6y ago
dastain 6y ago
Lovely, as other tools by Skilldrick. I've used Easy6502[1] before and forked it to customize it for a project of mine. I was just about to install Forth on an STM32 (blue pill) MCU, which is pretty nice![2] 1. https://skilldrick.github.io/easy6502/ https://skilldrick.github.io/easy6502/ 2. https://www.youtube.com/watch?v=dvTI3KmcZ7I https://www.youtube.com/watch?v=dvTI3KmcZ7I
fifilura 6y ago
It feels like I am running an emulator for my high-school HP-11 RPN calculator!
zabzonk 6y ago
I've written a couple of FORTH-like implementations - one way back when on a Z80 system, when I was learning Z80 assembler, running CP/M, and one on an IBM PC (the original kind, with clicky keyboard) when I was learning 8086 assembler and a bit of C++, as part of an adventure-writing system. Unfortunately, the code for both has got lost (no git back then), but I can strongly recommend writing a FORTH as a way of learning a new (non-FORTH) language.

100 points by guerrilla 6y ago

Munksgaard 6y ago

This is great! Forth is such an interesting language. Does anyone know of uses in industry?

rwmj 6y ago
Not sure if it counts as "industry" but FORTH-based Open Firmware is still used as a bootloader for some PowerPC machines. You can try this out under qemu: $ qemu-system-ppc64 VNC server running on ::1:5900 $ vncviewer :0 Ready! 0 > 1 2 3 * + . 7 ok 0 > WORDS (gigantic list of built-in words ...)
- exikyut 6y ago
  And FWIW Open Firmware runs on x86 too.
jonsen 6y ago
Third line of the introduction: “...is still used today for certain applications.” and is clickable.
guerrilla 6y ago
According to Wikipedia[1] it's used in astronomy and aerospace. It's also used in OpenFirmware like in old PowerPC Mac and IBM computers. 1. https://en.m.wikipedia.org/wiki/Forth_(programming_language) https://en.m.wikipedia.org/wiki/Forth_(programming_language)
s-macke 6y ago
In the gaming industry. The game Starflight was written in Forth. https://en.wikipedia.org/wiki/Starflight https://en.wikipedia.org/wiki/Starflight Ok, this is an ancient example. But still :-) The source code is partially available. Here one example. https://web.archive.org/web/20030906110447/http://www.sonic.net/~sage/sf/src/SOURCE-11-05-85/BANK_CMP.pdf https://web.archive.org/web/20030906110447/http://www.sonic....
MaxBarraclough 6y ago
See: • https://www.forth.com/resources/who-uses-forth/ https://www.forth.com/resources/who-uses-forth/ • https://vfxforth.com/#customers https://vfxforth.com/#customers (Curiously this also turned up on another thread, https://news.ycombinator.com/item?id=26165804 https://news.ycombinator.com/item?id=26165804 )
dastain 6y ago
You can install it on MCUs and use it to debug code pretty easily and makes it really nice to use reflection[1]. This use is not necessarily limited to enthusiasts, since nowadays even Arduino ends up in commercial products. While the language itself it's considered difficult to read by some, it's a great way to access MCUs features in a stack-based way and at a level higher than assembly. 1. https://www.youtube.com/watch?v=dvTI3KmcZ7I https://www.youtube.com/watch?v=dvTI3KmcZ7I
lebuffon 6y ago
The Fedex handheld terminal was re-written in Forth... twice. :) First time all the features wouldn't fit. Forth re-write fit with room to spare. (factoring is easy in Forth) New Hardware! Everything fit but batteries didn't last a full shift. :( Forth with a proprietary tasker put the device to sleep at every opportunity. Problem solved.
- Jtsummers 6y ago
  > factoring is easy in Forth Even more than working in functional languages like SML, Forth (and RPL, my first stack language) taught me how to factor out code and remove/minimize duplication. It's just so obvious when using it where the duplication is, the hard part is coming up with decent names. But if a sequence of words can be given a good name, give it that name and define it.
joubert 6y ago
Space.
JadeNB 6y ago
Here's an HN post on Forth in space! https://news.ycombinator.com/item?id=26164942 https://news.ycombinator.com/item?id=26164942

bmitc 6y ago

Forth is just fun.

MaxBarraclough 6y ago
You're still thinking in infix notation! FUN FORTH IS
- joubert 6y ago
  Missing the tone. :-)

jonsen 6y ago

How do you press “the Enter key” on an iPad? My operators are just stacked with Return.

exikyut 6y ago
For reference, what does the iOS keyboard you're seeing look like? Selecting the text field in Android just pops up my selected keyboard (Gboard), which includes an Enter key.
- jonsen 6y ago
  I use the standard keyboard. Don’t know what I can compare the look of it with. I’ve never seen or used an Android device. Maybe I can find a keyboard app with an Enter key.

ilaksh 6y ago

Check out ColorForth. Or RaonbowForth online http://rainbowforth.appspot.com/ http://rainbowforth.appspot.com/ https://youtu.be/N1FUY6g5crA https://youtu.be/N1FUY6g5crA

mikewarot 6y ago

I'm amazed that it worked so well, it did confuse me that each repl didn't know the previously defined functions, is that just me? Forth is almost the postfix inverse of lisp. Instead of arity errors, you have stack over and underflow. And it only has one list, instead of lists of lists. Oh, and it's not garbage collected Oh, it it's not homoiconic {edit]I guess it's really not the same thing at all Amazing how a day's exposure to Racket shifted my opinion

mumblemumble 6y ago
> Oh, it it's not homoiconic Is it as homoiconic as it needs to be? It's been a while since I've played with it in any real way, but, as I recall, Forth represents both data and code in exactly the same way: Blobs of data with no associated type information, that you're allowed to fiddle in any way you want, with no guard rails. So it seems like there's no reason you couldn't write some words for manipulating code every bit as easily as you could write some words for manipulating any other data. Lisp gives you a lot more out of the box, of course. But Lisp gives you a lot more of everything out of the box.
- astrobe_ 6y ago
  It depends on the implementation. With Indirect Threaded Code (ITC), "functions" are represented more or less as a list of other functions or primitives to call. But there are also classic bytecode-based Forth implementations, subroutine threaded code implementation (which is a simple form of native code generation), etc. In my experience, Forth's "immediate" words, which let you execute code at compile time, combined with the availability of some (or most) of the compiler's part, let you do quite a lot of things. In other words, you don't manipulate code, you directly generate code. For instance, if your implementation does not have 1+ (silly example), you can make a word "1+" that compiles "1 +" inline (or increment the top of stack if you interpret stuff from the REPL). To answer your question, I use a dialect of Forth that has, I think, less capabilities than standard Forth in this area and rarely felt the need to implement them. At the risk of showing I am a blub programmer, I think homoiconicity is overrated - for the user (for language implementers maybe it's another story).
- 6y ago

dastain 6y ago

Lovely, as other tools by Skilldrick. I've used Easy6502[1] before and forked it to customize it for a project of mine. I was just about to install Forth on an STM32 (blue pill) MCU, which is pretty nice![2] 1. https://skilldrick.github.io/easy6502/ https://skilldrick.github.io/easy6502/ 2. https://www.youtube.com/watch?v=dvTI3KmcZ7I https://www.youtube.com/watch?v=dvTI3KmcZ7I

fifilura 6y ago

It feels like I am running an emulator for my high-school HP-11 RPN calculator!

zabzonk 6y ago

I've written a couple of FORTH-like implementations - one way back when on a Z80 system, when I was learning Z80 assembler, running CP/M, and one on an IBM PC (the original kind, with clicky keyboard) when I was learning 8086 assembler and a bit of C++, as part of an adventure-writing system. Unfortunately, the code for both has got lost (no git back then), but I can strongly recommend writing a FORTH as a way of learning a new (non-FORTH) language.