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Though i only know Prolog cursorily it is in my todo list of languages to study. I think it has great value in that it teaches you a different paradigm for prog

Though i only know Prolog cursorily it is in my todo list of languages to study. I think it has great value in that it teaches you a different paradigm for programming. You might also want to look at Erlang which is used in the Industry and would be helpful for your future. Joe Armstrong was originally inspired by Prolog and he conceived Erlang as Prolog-Ideas+Functional/Procedural+Concurrency+Fault-Tolerance. Hence you might find a lot of commonalities here. Here is a recent HN thread on a comparison - https://news.ycombinator.com/item?id=40521585 https://news.ycombinator.com/item?id=40521585 There is also "Erlog" (by Robert Virding, one of the co-creators of Erlang) which is described as, Erlog is a Prolog interpreter implemented in Erlang and integrated with the Erlang runtime system. It is a subset of the Prolog standard. An Erlog shell (REPL) is also included. It also says, If you want to pass data between Erlang and Prolog it is pretty easy to do so. Data types map pretty cleanly between the two languages due to the fact that Erlang evolved from Prolog. - https://github.com/rvirding/erlog https://github.com/rvirding/erlog

btbuildem 2y ago
Ha! That explains a lot. I've started looking into Prolog recently, and there were some... familiar echoes in there, reminiscent of Erlang. But of course, the submarine is like a cigar, not cigar like a submarine.
- rramadass 2y ago
  The Development of Erlang by Joe Armstrong (pdf) - https://dl.acm.org/doi/pdf/10.1145/258948.258967 https://dl.acm.org/doi/pdf/10.1145/258948.258967
tannhaeuser 2y ago
Sure, Erlang was prototyped on Prolog because Prolog has excellent built-in facilities for domain-specific languages: you can define new unary or binary operators along with priorities and associativity rules (you can use this to implement JSON or other expression parsing in like two lines of code, which is kindof shocking for newcomers, but comes very handy for integrating Prolog "microservices" into backend stacks), and you get recursive-decent parsing with backtracking for free as a trivial specialization of Prolog evaluation with a built-in short syntax (definite clause grammars) even. But apart from syntax, Erlang has quite different goals as a backend language for interruption-free telco equipment compared to Prolog.
- rramadass 2y ago
  In The Development of Erlang Joe Armstrong says "We concluded that we would like something like Prolog with added facilities for concurrency and improved error handling". See pdf linked here - https://news.ycombinator.com/item?id=40998632 https://news.ycombinator.com/item?id=40998632
  - derdi 2y ago
    You're reading too much into that quote. This is in a section titled "early experiments". It was an initial goal. There is a lot of historical connection to Prolog, due to the original implementation, and there are syntactic similarities and non-linear pattern matching and dynamic types and a general declarative vibe, but the actual end result of Erlang's evolution, despite the goal of "something like Prolog", is not very much like Prolog at all. Erlang is a functional language, not a logic language. Prolog is a logic language, not a functional language. General goals like in that quote can change over the decade-long development of a language.
    - rramadass 2y ago
      You are stating some obvious things which are not what is being argued here. I only gave the above quote because it is the conclusion that the Erlang designers came to after a lot of research/playing/implementing with other languages (read the full paper and others listed below). I had also stated above that "he conceived Erlang as Prolog-Ideas+Functional/Procedural+Concurrency+Fault-Tolerance." So we already know Erlang is a different language. Note that Robert Virding also states in the Erlog page "due to the fact that Erlang evolved from Prolog". So obviously Prolog was a huge influence on Erlang design (not to be confused with the fact that the first experimentation was done in Prolog) in addition to other systems/languages. The above paper also states "It was a strange mixture, with declarative features (inherited from Prolog), multi-tasking and concurrency (inherited from EriPascal and Ada) and an original combination of error handling mechanisms". The last came from AXE/PLEX and others. Joe Armstrong wrote two papers The Development of Erlang (linked here https://news.ycombinator.com/item?id=40998632 https://news.ycombinator.com/item?id=40998632) and a longer A History of Erlang (pdf at https://www.labouseur.com/courses/erlang/history-of-erlang-armstrong.pdf https://www.labouseur.com/courses/erlang/history-of-erlang-a...). In addition to his thesis (pdf at https://erlang.org/download/armstrong_thesis_2003.pdf https://erlang.org/download/armstrong_thesis_2003.pdf) they provide a fascinating study into what goes into the design of a language i.e. lots of messy experiments, shifting goals, inspiration/features from many different languages etc. until everything coalesces into a organic whole which is then validated by users. Reading the above two papers will give you a more complete picture of Prolog's influence on Erlang (in addition to others).

btbuildem 2y ago

Ha! That explains a lot. I've started looking into Prolog recently, and there were some... familiar echoes in there, reminiscent of Erlang. But of course, the submarine is like a cigar, not cigar like a submarine.

rramadass 2y ago
The Development of Erlang by Joe Armstrong (pdf) - https://dl.acm.org/doi/pdf/10.1145/258948.258967 https://dl.acm.org/doi/pdf/10.1145/258948.258967

tannhaeuser 2y ago

Sure, Erlang was prototyped on Prolog because Prolog has excellent built-in facilities for domain-specific languages: you can define new unary or binary operators along with priorities and associativity rules (you can use this to implement JSON or other expression parsing in like two lines of code, which is kindof shocking for newcomers, but comes very handy for integrating Prolog "microservices" into backend stacks), and you get recursive-decent parsing with backtracking for free as a trivial specialization of Prolog evaluation with a built-in short syntax (definite clause grammars) even. But apart from syntax, Erlang has quite different goals as a backend language for interruption-free telco equipment compared to Prolog.

rramadass 2y ago
In The Development of Erlang Joe Armstrong says "We concluded that we would like something like Prolog with added facilities for concurrency and improved error handling". See pdf linked here - https://news.ycombinator.com/item?id=40998632 https://news.ycombinator.com/item?id=40998632
- derdi 2y ago
  You're reading too much into that quote. This is in a section titled "early experiments". It was an initial goal. There is a lot of historical connection to Prolog, due to the original implementation, and there are syntactic similarities and non-linear pattern matching and dynamic types and a general declarative vibe, but the actual end result of Erlang's evolution, despite the goal of "something like Prolog", is not very much like Prolog at all. Erlang is a functional language, not a logic language. Prolog is a logic language, not a functional language. General goals like in that quote can change over the decade-long development of a language.
  - rramadass 2y ago
    You are stating some obvious things which are not what is being argued here. I only gave the above quote because it is the conclusion that the Erlang designers came to after a lot of research/playing/implementing with other languages (read the full paper and others listed below). I had also stated above that "he conceived Erlang as Prolog-Ideas+Functional/Procedural+Concurrency+Fault-Tolerance." So we already know Erlang is a different language. Note that Robert Virding also states in the Erlog page "due to the fact that Erlang evolved from Prolog". So obviously Prolog was a huge influence on Erlang design (not to be confused with the fact that the first experimentation was done in Prolog) in addition to other systems/languages. The above paper also states "It was a strange mixture, with declarative features (inherited from Prolog), multi-tasking and concurrency (inherited from EriPascal and Ada) and an original combination of error handling mechanisms". The last came from AXE/PLEX and others. Joe Armstrong wrote two papers The Development of Erlang (linked here https://news.ycombinator.com/item?id=40998632 https://news.ycombinator.com/item?id=40998632) and a longer A History of Erlang (pdf at https://www.labouseur.com/courses/erlang/history-of-erlang-armstrong.pdf https://www.labouseur.com/courses/erlang/history-of-erlang-a...). In addition to his thesis (pdf at https://erlang.org/download/armstrong_thesis_2003.pdf https://erlang.org/download/armstrong_thesis_2003.pdf) they provide a fascinating study into what goes into the design of a language i.e. lots of messy experiments, shifting goals, inspiration/features from many different languages etc. until everything coalesces into a organic whole which is then validated by users. Reading the above two papers will give you a more complete picture of Prolog's influence on Erlang (in addition to others).