7 ms·

I have a question to all LISPers out there. It's just, cause I really don't know. I read a bit about LISP, but never used it or anything. Anyway. Here it is: W

by tete 14y ago

I have a question to all LISPers out there. It's just, cause I really don't know. I read a bit about LISP, but never used it or anything. Anyway. Here it is: Why not Scheme?

joshAg 14y ago
Isn't scheme just a dialect of lisp?
- Jacquass12321 14y ago
  Yes, it's a lighter (very minimalist) version of lisp, as opposed to common lisp. Scheme seemed like more of a fun academic exercise. If I wanted to actually do more complex work I'd probably look to common lisp instead of Scheme.
  - betterunix 14y ago
    Scheme does have a feature that would be handy in Common Lisp: continuations with indefinite extent. PG has an interesting way to simulate this with macros in On Lisp, but that hardly suffices. It is not something that I frequently need, but I have had one or two cases when such a continuation would have come in handy.
- klibertp 14y ago
  Both "Common Lisp" and various (!) Schemes are dialects of lisp. As for why CL is preferred - it's probably about the ecosystem, tools and libraries. No Scheme and very few languages can compete with CL in this matter. However there is Rachet, a Scheme that has a chance to approach CL in the next decade (only my opinion).
minikomi 14y ago
Piggybacking on this.. After reading SICP over the new year, I had a look into using Racket for various things, and although it seems to have an excellent, well rounded set of libraries and excellent documentation there seems to be less drive of people doing practical things with the language. Is there a glaring reason why, or is it simply lack of mindshare?
- codygman 14y ago
  I've came to the same conclusion, and I figure that if I (well we) don't start making cool practical things then no one ever will. Of course, you do know that the Arc language is racket code right? The site you are on is using racket ;)
chimeracoder 14y ago
LISP (or Lisp) is a family of languages, not a single language. There are two main categories of Lisp dialects, the Lisp-1s and the Lisp-2s. Scheme is a Lisp-1. Scheme is itself not a single language; it's a subcategory of Lisps. The main Scheme standard these days is R6RS (http://www.r6rs.org/ http://www.r6rs.org/), but different implementations may or may not comply with R6RS (Racket does not, for example, even though it was formerly known as PLT Scheme). Common Lisp is the most well-known Lisp-2, and is what's generally implied when people say 'Lisp', even though that's technically a sloppy use of terminology. Clojure is another dialect, but people generally specify Clojure and Scheme by name when referring to them. There is no logic behind these nuances of the terminology and their inconsistent usage; it's just what's evolved over the last 50+ years. So, to answer your question, there's no reason why one should learn Scheme over Common Lisp (or vice versa), if all you're looking to do is learn the concepts. There are differences between the different dialects (and their many implementations), but if you're looking to expand your knowledge and not necessarily write production code, pick Scheme (using Guile) and Common Lisp (using Clisp or SBCL) and you're good to go.
- pavelludiq 14y ago
  So, to answer your question, there's no reason why one should learn Scheme over Common Lisp (or vice versa), if all you're looking to do is learn the concepts. Once you scratch the surface, Scheme, Common Lisp and Clojure emphasize very different concepts, in some cases they even conflict in philosophy fundamentally. I'd say give all three a chance and pick a favorite. I picked Common Lisp, but that's just me.
  - zvrba 14y ago
    > Scheme, Common Lisp and Clojure emphasize very different concepts, As I discovered when I was looking for TAGBODY in scheme (don't ask; it seemed to be the most convenient way of solving the problem). Then I realized I didn't need it, I could get the same effect with internal definitions (internal function = tag) and calls. A call in tail position IS essentially a goto. (More powerful though as it also binds arguments, if any.) Scheme also looks more conceptually clean. For example, (define add +) does exactly what you think. In CL, you'd have to do something more contrived.
kruhft 14y ago
Because you have to write multiple-value-bind yourself, no &optional and &key parameters, no try/catch or condition system and verious other reasons. Scheme is case sensitive by default though, which I like. It's sort of like asking 'Why C++ and not C?'. It's the features or lack thereof that you have to want or not want that lead you to your initial decision. Then you switch to the other to see what you're missing. Then you make up your mind.
dkirkman 14y ago
There are a few good reasons that one might prefer common lisp to scheme. It has been stable for a good long time. Which is nice if you've got a giant repository of old code that you dust off and run from time to time. CL has a standard way of specifying variable types when you want to do so, so it's possible to write high performance numerical code in a portable (across different compilers) manner. Or write macros to write portable code. My view on macros is that being code transformers, when you write a macro you are basically writing a quick and dirty compiler. And like everything that's quick and dirty, they are full of bugs and gotchas. The fact that CL has separate function and value namespaces helps with decreasing the gotcha cross-section. The scheme community early on spent a lot of time dealing with this and developing hygienic macros, but as a lisper this just always felt a bit heavy. (This is probably just a lack of exposure). From my perspective, the appeal of scheme as been its more pure focus on functional programming. But when I'm in that sort of mood I just reach for haskell now.
- pnathan 14y ago
  > It has been stable for a good long time. Which is nice if you've got a giant repository of old code that you dust off and run from time to time. I think CL is one of the few languages that I can see myself using for a decade, continuously, without having to go back and refresh pieces to conform to the latest version & compiler. Not only that, you can essentially reprogram it to keep up with advances in the field.
tbirdz 14y ago
Check out this article here comparing Common Lisp and Scheme. I'm not the author, but I thought it was a really helpful overview of the differences between them, and I hope it will help you all too. http://symbo1ics.com/blog/?p=729 http://symbo1ics.com/blog/?p=729
rayiner 14y ago
Common Lisp doesn't (like at all) hew to conceptual elegance and so has a lot more useful stuff built in: 1) CLOS for object-oriented programming; 2) LOOP as a DSL for expressing complex iteration (http://www.gigamonkeys.com/book/loop-for-black-belts.html http://www.gigamonkeys.com/book/loop-for-black-belts.html); 3) Type declarations and a compiler (CMUCL/SBCL) that can take full advantage of them; 4) Better tooling (CMUCL/SBCL + SLIME); 5) More commercial support options (Clozure, LispWorks, Allegro). R5RS doesn't even have hash tables! You can patch together alternatives for Scheme for most of those things, but the fact that they're not built-in causes problems when integrating code from multiple sources.
- dragonwriter 14y ago
  > R5RS doesn't even have hash tables! R6RS does, though. > You can patch together alternatives for Scheme for most of those things, but the fact that they're not built-in causes problems when integrating code from multiple sources. R6RS has a lot more built-in than R5RS.
pnathan 14y ago
Which Scheme? Each Scheme system appears to be slightly and definitely incompatible with the others after a point. Unlike Common Lisp, which has a well-defined standard. Unlike Clojure, which, while evolving, is at least compatible with itself.
muuh-gnu 14y ago
Because 1001 different Schemes exist and the code between them is not portable because the Scheme standard is so tiny. Scheme code is so hopelessly unportable,that you can not even talk about "writing Scheme". You are either writing Gauche, or Chicken, or Racket, and once you write it, your code stays in that tiny little ecosystem with not more than 10 different users each.

by tete 14y ago

I have a question to all LISPers out there. It's just, cause I really don't know. I read a bit about LISP, but never used it or anything. Anyway. Here it is: Why not Scheme?

joshAg 14y ago

Isn't scheme just a dialect of lisp?

Jacquass12321 14y ago
Yes, it's a lighter (very minimalist) version of lisp, as opposed to common lisp. Scheme seemed like more of a fun academic exercise. If I wanted to actually do more complex work I'd probably look to common lisp instead of Scheme.
- betterunix 14y ago
  Scheme does have a feature that would be handy in Common Lisp: continuations with indefinite extent. PG has an interesting way to simulate this with macros in On Lisp, but that hardly suffices. It is not something that I frequently need, but I have had one or two cases when such a continuation would have come in handy.
klibertp 14y ago
Both "Common Lisp" and various (!) Schemes are dialects of lisp. As for why CL is preferred - it's probably about the ecosystem, tools and libraries. No Scheme and very few languages can compete with CL in this matter. However there is Rachet, a Scheme that has a chance to approach CL in the next decade (only my opinion).

minikomi 14y ago

Piggybacking on this.. After reading SICP over the new year, I had a look into using Racket for various things, and although it seems to have an excellent, well rounded set of libraries and excellent documentation there seems to be less drive of people doing practical things with the language. Is there a glaring reason why, or is it simply lack of mindshare?

codygman 14y ago
I've came to the same conclusion, and I figure that if I (well we) don't start making cool practical things then no one ever will. Of course, you do know that the Arc language is racket code right? The site you are on is using racket ;)

chimeracoder 14y ago

LISP (or Lisp) is a family of languages, not a single language. There are two main categories of Lisp dialects, the Lisp-1s and the Lisp-2s. Scheme is a Lisp-1. Scheme is itself not a single language; it's a subcategory of Lisps. The main Scheme standard these days is R6RS (http://www.r6rs.org/ http://www.r6rs.org/), but different implementations may or may not comply with R6RS (Racket does not, for example, even though it was formerly known as PLT Scheme). Common Lisp is the most well-known Lisp-2, and is what's generally implied when people say 'Lisp', even though that's technically a sloppy use of terminology. Clojure is another dialect, but people generally specify Clojure and Scheme by name when referring to them. There is no logic behind these nuances of the terminology and their inconsistent usage; it's just what's evolved over the last 50+ years. So, to answer your question, there's no reason why one should learn Scheme over Common Lisp (or vice versa), if all you're looking to do is learn the concepts. There are differences between the different dialects (and their many implementations), but if you're looking to expand your knowledge and not necessarily write production code, pick Scheme (using Guile) and Common Lisp (using Clisp or SBCL) and you're good to go.

pavelludiq 14y ago
So, to answer your question, there's no reason why one should learn Scheme over Common Lisp (or vice versa), if all you're looking to do is learn the concepts. Once you scratch the surface, Scheme, Common Lisp and Clojure emphasize very different concepts, in some cases they even conflict in philosophy fundamentally. I'd say give all three a chance and pick a favorite. I picked Common Lisp, but that's just me.
- zvrba 14y ago
  > Scheme, Common Lisp and Clojure emphasize very different concepts, As I discovered when I was looking for TAGBODY in scheme (don't ask; it seemed to be the most convenient way of solving the problem). Then I realized I didn't need it, I could get the same effect with internal definitions (internal function = tag) and calls. A call in tail position IS essentially a goto. (More powerful though as it also binds arguments, if any.) Scheme also looks more conceptually clean. For example, (define add +) does exactly what you think. In CL, you'd have to do something more contrived.

kruhft 14y ago

Because you have to write multiple-value-bind yourself, no &optional and &key parameters, no try/catch or condition system and verious other reasons. Scheme is case sensitive by default though, which I like. It's sort of like asking 'Why C++ and not C?'. It's the features or lack thereof that you have to want or not want that lead you to your initial decision. Then you switch to the other to see what you're missing. Then you make up your mind.

dkirkman 14y ago

There are a few good reasons that one might prefer common lisp to scheme. It has been stable for a good long time. Which is nice if you've got a giant repository of old code that you dust off and run from time to time. CL has a standard way of specifying variable types when you want to do so, so it's possible to write high performance numerical code in a portable (across different compilers) manner. Or write macros to write portable code. My view on macros is that being code transformers, when you write a macro you are basically writing a quick and dirty compiler. And like everything that's quick and dirty, they are full of bugs and gotchas. The fact that CL has separate function and value namespaces helps with decreasing the gotcha cross-section. The scheme community early on spent a lot of time dealing with this and developing hygienic macros, but as a lisper this just always felt a bit heavy. (This is probably just a lack of exposure). From my perspective, the appeal of scheme as been its more pure focus on functional programming. But when I'm in that sort of mood I just reach for haskell now.

pnathan 14y ago
> It has been stable for a good long time. Which is nice if you've got a giant repository of old code that you dust off and run from time to time. I think CL is one of the few languages that I can see myself using for a decade, continuously, without having to go back and refresh pieces to conform to the latest version & compiler. Not only that, you can essentially reprogram it to keep up with advances in the field.

tbirdz 14y ago

Check out this article here comparing Common Lisp and Scheme. I'm not the author, but I thought it was a really helpful overview of the differences between them, and I hope it will help you all too. http://symbo1ics.com/blog/?p=729 http://symbo1ics.com/blog/?p=729

rayiner 14y ago

Common Lisp doesn't (like at all) hew to conceptual elegance and so has a lot more useful stuff built in: 1) CLOS for object-oriented programming; 2) LOOP as a DSL for expressing complex iteration (http://www.gigamonkeys.com/book/loop-for-black-belts.html http://www.gigamonkeys.com/book/loop-for-black-belts.html); 3) Type declarations and a compiler (CMUCL/SBCL) that can take full advantage of them; 4) Better tooling (CMUCL/SBCL + SLIME); 5) More commercial support options (Clozure, LispWorks, Allegro). R5RS doesn't even have hash tables! You can patch together alternatives for Scheme for most of those things, but the fact that they're not built-in causes problems when integrating code from multiple sources.

dragonwriter 14y ago
> R5RS doesn't even have hash tables! R6RS does, though. > You can patch together alternatives for Scheme for most of those things, but the fact that they're not built-in causes problems when integrating code from multiple sources. R6RS has a lot more built-in than R5RS.

pnathan 14y ago

Which Scheme? Each Scheme system appears to be slightly and definitely incompatible with the others after a point. Unlike Common Lisp, which has a well-defined standard. Unlike Clojure, which, while evolving, is at least compatible with itself.

muuh-gnu 14y ago

Because 1001 different Schemes exist and the code between them is not portable because the Scheme standard is so tiny. Scheme code is so hopelessly unportable,that you can not even talk about "writing Scheme". You are either writing Gauche, or Chicken, or Racket, and once you write it, your code stays in that tiny little ecosystem with not more than 10 different users each.