5 ms·

Glad to see Forth getting some attention, took me around 25 years of coding to find it. For those looking for a different take on the same ideas, I'm working o

by sifoo 9y ago

Glad to see Forth getting some attention, took me around 25 years of coding to find it. For those looking for a different take on the same ideas, I'm working on a Lisp-inspired Forth here: https://github.com/basic-gongfu/cixl https://github.com/basic-gongfu/cixl

cy_hauser 9y ago
Whoa. I'm afraid to look ;-) My immediate thought is, "lets combine all the mental fun of stack juggling from forth with the tree juggling from lisp." My brain hurts!
- groovy2shoes 9y ago
  Combining aspects of Lisp with aspects of Forth is not a new idea. The RPN calculators offered by HP used a language called RPL ("Reverse Polish Lisp")[1], including a user-level version (a little more Lisp-y) and a system-level version (a little more Forth-y). While RPL is what came immediately to my mind, I doubt it's the only historical example of such a combination; people have been drawing similarities between the Lisp family and the Forth family for ages. [1]: https://en.wikipedia.org/wiki/RPL_(programming_language) https://en.wikipedia.org/wiki/RPL_(programming_language)
  - sifoo 9y ago
    Thank you! PostScript is another example.
    - groovy2shoes 9y ago
      While I do get that feel with PostScript, as far as I can tell it was accidental rather than a conscious design decision. The stack-oriented nature of PostScript appears to have been influenced by the engineers' experiences with working with some stack-oriented architectures from Burroughs [1], rather than from Forth. Some aspects of PostScript were influenced heavily by other languages in use at Xerox PARC during the Interpress era [ibid], most notably Cedar, but considering that Interlisp was also in use at the time, it's not unreasonable to conjecture that it had some influence; however, any such Lisp influence was likely subconscious, and none of the people working on Interpress or PostScript or their forebears seems to explicated such an influence (as far as I can find). Charles Geschke and John Warnock, the co-founders of Adobe, both deny any influence from Forth, suspecting that some overlap of design requirements between the two languages led to the shared properties [2]. I know that can be hard to believe, given the striking similarity of the two languages, but it's not the only time that concatenative programming would have been independently invented: Manfred von Thun's Joy language is likewise similar to Forth, but, again, not inspired by it. Whereas the similarity of PostScript to Forth can be explained by a simultaneous need for portability and dynamism in tightly-constrained environments, Joy's similarity to Forth is a result of a desire for algebraic manipulation of program text (Forth's (somewhat) having this property may have been a conscious design decision, but I'd bet cold, hard cash that it was a happy accident). Indeed, any of these stack-oriented concatenative languages are computationally equivalent to a transformation monoid (algebra of functions and function composition) where evaluation proceeds according to a (possibly effectful) term-rewriting relation. Viewed in this light, the stack effectively becomes a mere implementation detail as far as the semantics are concerned, but I think that any language designer starting with such a monoid+rewriting semantics, when facing reasonable implementation on real hardware, is likely to come up with something quite similar to Forth &c. That is to say, starting with a low-level focus on efficient and portable implementation, or starting with a high-level focus on code representation as algebraic terms, there's a good chance you'll wind up with something similar to an established concatenative language, whether you mean to or not. --- [1]: "PostScript and Interpress: a comparison", Brian Reid: http://tech-insider.org/unix/research/1985/0301.html http://tech-insider.org/unix/research/1985/0301.html [2]: Masterminds of Programming, Federico Biancuzzi & Shane Warden (eds.)
      - sifoo 9y ago
        Hidden deep inside almost any other language sits a tiny Forth; often chained to a wall out of sight from user code and restricted to evaluating expressions and shuffling function arguments/results, but still. That's about as fundamental as you can get without dropping down to assembly. Ever since I realized this, I've been itching to see what a Lisp that embraces its inner Forth could do. I wouldn't be surprised if the people who came before me saw some aspect of the same archetype.
- sifoo 9y ago
  Besides basic semantics, there's not that much stack juggling going on really. Cixl offers four stack operators, drop, dup, swap and clear; the idea is to use more convenient constructs like let bindings, closures and multi methods to keep the stack tidy.

by sifoo 9y ago

cy_hauser 9y ago

Whoa. I'm afraid to look ;-) My immediate thought is, "lets combine all the mental fun of stack juggling from forth with the tree juggling from lisp." My brain hurts!

groovy2shoes 9y ago
Combining aspects of Lisp with aspects of Forth is not a new idea. The RPN calculators offered by HP used a language called RPL ("Reverse Polish Lisp")[1], including a user-level version (a little more Lisp-y) and a system-level version (a little more Forth-y). While RPL is what came immediately to my mind, I doubt it's the only historical example of such a combination; people have been drawing similarities between the Lisp family and the Forth family for ages. [1]: https://en.wikipedia.org/wiki/RPL_(programming_language) https://en.wikipedia.org/wiki/RPL_(programming_language)
- sifoo 9y ago
  Thank you! PostScript is another example.
  - groovy2shoes 9y ago
    While I do get that feel with PostScript, as far as I can tell it was accidental rather than a conscious design decision. The stack-oriented nature of PostScript appears to have been influenced by the engineers' experiences with working with some stack-oriented architectures from Burroughs [1], rather than from Forth. Some aspects of PostScript were influenced heavily by other languages in use at Xerox PARC during the Interpress era [ibid], most notably Cedar, but considering that Interlisp was also in use at the time, it's not unreasonable to conjecture that it had some influence; however, any such Lisp influence was likely subconscious, and none of the people working on Interpress or PostScript or their forebears seems to explicated such an influence (as far as I can find). Charles Geschke and John Warnock, the co-founders of Adobe, both deny any influence from Forth, suspecting that some overlap of design requirements between the two languages led to the shared properties [2]. I know that can be hard to believe, given the striking similarity of the two languages, but it's not the only time that concatenative programming would have been independently invented: Manfred von Thun's Joy language is likewise similar to Forth, but, again, not inspired by it. Whereas the similarity of PostScript to Forth can be explained by a simultaneous need for portability and dynamism in tightly-constrained environments, Joy's similarity to Forth is a result of a desire for algebraic manipulation of program text (Forth's (somewhat) having this property may have been a conscious design decision, but I'd bet cold, hard cash that it was a happy accident). Indeed, any of these stack-oriented concatenative languages are computationally equivalent to a transformation monoid (algebra of functions and function composition) where evaluation proceeds according to a (possibly effectful) term-rewriting relation. Viewed in this light, the stack effectively becomes a mere implementation detail as far as the semantics are concerned, but I think that any language designer starting with such a monoid+rewriting semantics, when facing reasonable implementation on real hardware, is likely to come up with something quite similar to Forth &c. That is to say, starting with a low-level focus on efficient and portable implementation, or starting with a high-level focus on code representation as algebraic terms, there's a good chance you'll wind up with something similar to an established concatenative language, whether you mean to or not. --- [1]: "PostScript and Interpress: a comparison", Brian Reid: http://tech-insider.org/unix/research/1985/0301.html http://tech-insider.org/unix/research/1985/0301.html [2]: Masterminds of Programming, Federico Biancuzzi & Shane Warden (eds.)
    - sifoo 9y ago
      Hidden deep inside almost any other language sits a tiny Forth; often chained to a wall out of sight from user code and restricted to evaluating expressions and shuffling function arguments/results, but still. That's about as fundamental as you can get without dropping down to assembly. Ever since I realized this, I've been itching to see what a Lisp that embraces its inner Forth could do. I wouldn't be surprised if the people who came before me saw some aspect of the same archetype.
sifoo 9y ago
Besides basic semantics, there's not that much stack juggling going on really. Cixl offers four stack operators, drop, dup, swap and clear; the idea is to use more convenient constructs like let bindings, closures and multi methods to keep the stack tidy.