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Not sure if you've seen this one: http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_H

Not sure if you've seen this one: http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_Hours http://en.wikibooks.org/wiki/Write_Yourself_a_Scheme_in_48_H... I haven't done it, but I hear its excellent.

muuh-gnu 14y ago
It would be even more excellent if people for a change wrote more _in_ scheme instead of _a_ scheme.
- chimeracoder 14y ago
  Why write a program that gets your job done when you can just as easily write a language that makes writing that program trivial? (I'm only being partly tongue-in-cheek - that's mentality behind idiomatic Lisp).
- dizzystar 14y ago
  It would be the equivalent to writing Java on top of Haskell. You wouldn't creat Java, you would be creating _a_ Java. "Scheme" has many different dialects as well. Racket is _a_ Scheme, Edwin interprets MIT's version of Scheme, then there is Gambit Scheme. There are certainly other Schemes, and the implementation of Scheme on Haskell isn't going to be the same as the other dialects listed here. There are quite a few examples of Prolog-to-Lisp interpreters, but no one would argue that any of these _are_ Prolog.
tikhonj 14y ago
This was how I learned Haskell. I rather liked it. That said, looking back, I'm not sure it encourages the best coding style or the best idioms. It's perfect for getting your head around the paradigm though! I'm currently writing an analogous tutorial for implementing Prolog in Haskell, but it's on a bit of a hiatus thanks to some school and research related deadlines coming up. Hopefully people are interested in something like that :). Interestingly enough, the Prolog interpreter is actually shorter than the simple Scheme one--largely because we can take advantage of the list monad for the backtracking. I think it's still a very cool exercise.
- X6MW3aQrZU5VKkz 14y ago
  I would be very interested in seeing a tutorial detailing how to implement Prolog in Haskell!
  - exDM69 14y ago
    Not really a tutorial and not really Prolog, but here's an interpreter for a logic programming language written in Haskell: https://github.com/rikusalminen/slolog https://github.com/rikusalminen/slolog I wrote it as a project work in an Artificial Intelligence class. It very closely resembles the logic programming language implemented in "Structure and Interpretation of Computer Programs". I'm sorry there isn't any documentation for it. Here's a little example of what it looks like, from examples/royalfamily.slo: (siblings ?x ?y) <- (parent ?x ?parent) & (parent ?y ?parent) (grandparent ?x ?y) <- (parent ?x ?z) & (parent ?z ?y) (cousins ?x ?y) <- (grandparent ?x ?gp) & (grandparent ?y ?gp) & !(siblings ?x ?y)
- chadzawistowski 14y ago
  That sounds awesome! I'd be very interested in that prolog interpreter tutorial.
el_devo 14y ago
I would say this tutorial is an excellent one to read through when you are first learning Haskell, and then return to it later when you have a better understanding of the language. Some important concepts are glazed over, and you will almost certainly not understand what is going on the first time you read the tutorial. Once you are comfortable with Haskell the code makes much more sense and is a great starting point for writing an interpreter of your own.

muuh-gnu 14y ago

It would be even more excellent if people for a change wrote more _in_ scheme instead of _a_ scheme.

chimeracoder 14y ago
Why write a program that gets your job done when you can just as easily write a language that makes writing that program trivial? (I'm only being partly tongue-in-cheek - that's mentality behind idiomatic Lisp).
dizzystar 14y ago
It would be the equivalent to writing Java on top of Haskell. You wouldn't creat Java, you would be creating _a_ Java. "Scheme" has many different dialects as well. Racket is _a_ Scheme, Edwin interprets MIT's version of Scheme, then there is Gambit Scheme. There are certainly other Schemes, and the implementation of Scheme on Haskell isn't going to be the same as the other dialects listed here. There are quite a few examples of Prolog-to-Lisp interpreters, but no one would argue that any of these _are_ Prolog.

tikhonj 14y ago

This was how I learned Haskell. I rather liked it. That said, looking back, I'm not sure it encourages the best coding style or the best idioms. It's perfect for getting your head around the paradigm though! I'm currently writing an analogous tutorial for implementing Prolog in Haskell, but it's on a bit of a hiatus thanks to some school and research related deadlines coming up. Hopefully people are interested in something like that :). Interestingly enough, the Prolog interpreter is actually shorter than the simple Scheme one--largely because we can take advantage of the list monad for the backtracking. I think it's still a very cool exercise.

X6MW3aQrZU5VKkz 14y ago
I would be very interested in seeing a tutorial detailing how to implement Prolog in Haskell!
- exDM69 14y ago
  Not really a tutorial and not really Prolog, but here's an interpreter for a logic programming language written in Haskell: https://github.com/rikusalminen/slolog https://github.com/rikusalminen/slolog I wrote it as a project work in an Artificial Intelligence class. It very closely resembles the logic programming language implemented in "Structure and Interpretation of Computer Programs". I'm sorry there isn't any documentation for it. Here's a little example of what it looks like, from examples/royalfamily.slo: (siblings ?x ?y) <- (parent ?x ?parent) & (parent ?y ?parent) (grandparent ?x ?y) <- (parent ?x ?z) & (parent ?z ?y) (cousins ?x ?y) <- (grandparent ?x ?gp) & (grandparent ?y ?gp) & !(siblings ?x ?y)
chadzawistowski 14y ago
That sounds awesome! I'd be very interested in that prolog interpreter tutorial.

el_devo 14y ago

I would say this tutorial is an excellent one to read through when you are first learning Haskell, and then return to it later when you have a better understanding of the language. Some important concepts are glazed over, and you will almost certainly not understand what is going on the first time you read the tutorial. Once you are comfortable with Haskell the code makes much more sense and is a great starting point for writing an interpreter of your own.