4 ms·

The presence in Clojure of persistent vectors and hashmaps, which are very, very fast, and are used pervasively throughout the core libraries and Clojure code a

by graue 13y ago

The presence in Clojure of persistent vectors and hashmaps, which are very, very fast, and are used pervasively throughout the core libraries and Clojure code at large, makes it way more interesting to me than other Lisps I've seen. Does modern Racket have anything comparable to Clojure's collection primitives? My introduction to Lisp, some years ago, was reading The Little Schemer, which I loved. Afterwards, I was very disillusioned when I needed an array and learned the canonical solution was to use mutable arrays and set! (as if adding a bang after its name made it less of a sin). I understand why it's like that: persistent data structures are tricky to implement efficiently, and Scheme emphasizes simplicity of implementation. But it still bums me out.

6cxs2hd6 13y ago
Standard datatypes and generics (including hash tables, dictionaries, vectors, sets, sequences, streams, etc.): http://docs.racket-lang.org/reference/data.html http://docs.racket-lang.org/reference/data.html Additional datatypes (including imperative queues, growable vectors, orders and ordered dictionaries, splay trees, skip lists, interval maps, binary heaps, integer sets, bit vectors, etc.): http://docs.racket-lang.org/data/index.html http://docs.racket-lang.org/data/index.html
- chongli 13y ago
  Are all of those standard datatypes thread-safe? If not, they are not what the parent was asking for. Clojure's maps, sets and vectors are all thread-safe due to being immutable. They're all built-in to the standard library and have extremely slick syntactic sugar. Sure, you could implement all of this in Racket, I'm not saying you couldn't; the advantage with Clojure is that these things are standard and that everybody else's libraries make use of this stuff. This is probably the biggest advantage with starting any new programming language: you get a chance to redo the standard library (and tie it into some syntactic sugar) without worrying about compatibility.
  - klibertp 13y ago
    > Are all of those standard datatypes thread-safe? Some of them have both mutable and immutable versions (lists, hashes) where immutability is the default, some are purely functional (Okasaki's data structures implementation https://pkg.racket-lang.org/info/pfds https://pkg.racket-lang.org/info/pfds), and some are mutable by default (the "data" package). Most of the stdlib is immutable by default or plain immutable. There is no "slick" syntactic sugar for these by default, but Racket being as good in "language creation" department as it is, there are 3rd party implementations (https://github.com/greghendershott/rackjure https://github.com/greghendershott/rackjure). > the advantage with Clojure is that these things are standard and that everybody else's libraries make use of this stuff For the most part it is true for Racket, too. Where it differs is syntactic sugar and more complex data structures; I think some of this will change in racket2 (which is being planned if I understand correctly). > you get a chance to redo the standard library (and tie it into some syntactic sugar) without worrying about compatibility. That's why every "racket" program starts with a #lang specifier. Racket, in reality, is many different languages at once; because of this design and matching implementation, there is absolutely no problem with redoing stdlib and syntax completely - you can write Racket that is lazy, that is FRP, that is Algol(try it, it's fun!) that is typed or is logic oriented (http://en.wikipedia.org/wiki/Datalog http://en.wikipedia.org/wiki/Datalog) already. And you can mix modules written in them freely and conveniently (provide in one and require form in the other module are all it takes in practice). This alone makes Racket so much more flexible than any other language. What Racket lacks now to implement everything Clojure (and other languages) offers as one of the Racket languages are only man-hours of development team. Other, less complicated features from other languages are being ported all the time, for example generator function in a Python style (with yield) implementation is in a stdlib since a long time, so I believe assimilating proven concepts from other languages is both possible and a "Racket way".
    - chongli 13y ago
      Yeah, it really sounds like Racket is the most flexible programming language out there due to its metalinguistic abstraction capability. The question is: what is the secret to attracting developers to join the community? Clojure seems to really benefit from the rather iconic personality of Rich Hickey; this is in common with other communities and their leaders. The other thing I wonder is if there is such a thing as too flexible? Rich deliberately resisted adding user-definable reader macros because he wanted Clojure to have a consistent, identifiable syntax. Whether that benefits the language's adoption or not, I have no idea. I have to say I am hopeful that more people are exposed to Lisp languages on all fronts and that it cross-polinates all of the communities. We all have much to learn from one another and a great deal of potential for innovation. Despite how old Lisp is it still seems like we've barely scratched the surface of its potential.
ruricolist 13y ago
Clojure's persistent vectors and hashmaps are both the same data structure, the hash array mapped trie, which can be implemented both simply and efficiently. If you look at the Java code in the Clojure source, there are no tricks, beyond the cleverness of the HAMT itself.
klibertp 13y ago
> Does modern Racket have anything comparable to Clojure's collection primitives? See: https://news.ycombinator.com/item?id=6300845 https://news.ycombinator.com/item?id=6300845 Also, yes, there are generic "sequence" operations which you can use to abstract away a type of a collection you use. There are lazy sequences too, although they are not the default. There is also a set of very powerful "for" forms, which are an alternative to recursion when traversing sequences (and can function as sequence comprehensions, too). > and Scheme emphasizes simplicity of implementation. But it still bums me out. There is a reason why Racket name was changed from PLT Scheme. Racket outgrow Scheme some time ago and continues to grow still. It is "Scheme with batteries included", which means it's not Scheme anymore. But it makes it a great language for practical applications. It's not that great for embedding, though, while normal Schemes are. Anyway, I find Racket to be the most impressive language I've seen until now. It could use some more developers working on it, but that's all it needs to become on par with Clojure - or any other language for that matter. This makes it's design truly impressive, in my opinion at least.

by graue 13y ago

6cxs2hd6 13y ago

Standard datatypes and generics (including hash tables, dictionaries, vectors, sets, sequences, streams, etc.): http://docs.racket-lang.org/reference/data.html http://docs.racket-lang.org/reference/data.html Additional datatypes (including imperative queues, growable vectors, orders and ordered dictionaries, splay trees, skip lists, interval maps, binary heaps, integer sets, bit vectors, etc.): http://docs.racket-lang.org/data/index.html http://docs.racket-lang.org/data/index.html

chongli 13y ago
Are all of those standard datatypes thread-safe? If not, they are not what the parent was asking for. Clojure's maps, sets and vectors are all thread-safe due to being immutable. They're all built-in to the standard library and have extremely slick syntactic sugar. Sure, you could implement all of this in Racket, I'm not saying you couldn't; the advantage with Clojure is that these things are standard and that everybody else's libraries make use of this stuff. This is probably the biggest advantage with starting any new programming language: you get a chance to redo the standard library (and tie it into some syntactic sugar) without worrying about compatibility.
- klibertp 13y ago
  > Are all of those standard datatypes thread-safe? Some of them have both mutable and immutable versions (lists, hashes) where immutability is the default, some are purely functional (Okasaki's data structures implementation https://pkg.racket-lang.org/info/pfds https://pkg.racket-lang.org/info/pfds), and some are mutable by default (the "data" package). Most of the stdlib is immutable by default or plain immutable. There is no "slick" syntactic sugar for these by default, but Racket being as good in "language creation" department as it is, there are 3rd party implementations (https://github.com/greghendershott/rackjure https://github.com/greghendershott/rackjure). > the advantage with Clojure is that these things are standard and that everybody else's libraries make use of this stuff For the most part it is true for Racket, too. Where it differs is syntactic sugar and more complex data structures; I think some of this will change in racket2 (which is being planned if I understand correctly). > you get a chance to redo the standard library (and tie it into some syntactic sugar) without worrying about compatibility. That's why every "racket" program starts with a #lang specifier. Racket, in reality, is many different languages at once; because of this design and matching implementation, there is absolutely no problem with redoing stdlib and syntax completely - you can write Racket that is lazy, that is FRP, that is Algol(try it, it's fun!) that is typed or is logic oriented (http://en.wikipedia.org/wiki/Datalog http://en.wikipedia.org/wiki/Datalog) already. And you can mix modules written in them freely and conveniently (provide in one and require form in the other module are all it takes in practice). This alone makes Racket so much more flexible than any other language. What Racket lacks now to implement everything Clojure (and other languages) offers as one of the Racket languages are only man-hours of development team. Other, less complicated features from other languages are being ported all the time, for example generator function in a Python style (with yield) implementation is in a stdlib since a long time, so I believe assimilating proven concepts from other languages is both possible and a "Racket way".
  - chongli 13y ago
    Yeah, it really sounds like Racket is the most flexible programming language out there due to its metalinguistic abstraction capability. The question is: what is the secret to attracting developers to join the community? Clojure seems to really benefit from the rather iconic personality of Rich Hickey; this is in common with other communities and their leaders. The other thing I wonder is if there is such a thing as too flexible? Rich deliberately resisted adding user-definable reader macros because he wanted Clojure to have a consistent, identifiable syntax. Whether that benefits the language's adoption or not, I have no idea. I have to say I am hopeful that more people are exposed to Lisp languages on all fronts and that it cross-polinates all of the communities. We all have much to learn from one another and a great deal of potential for innovation. Despite how old Lisp is it still seems like we've barely scratched the surface of its potential.

ruricolist 13y ago

Clojure's persistent vectors and hashmaps are both the same data structure, the hash array mapped trie, which can be implemented both simply and efficiently. If you look at the Java code in the Clojure source, there are no tricks, beyond the cleverness of the HAMT itself.

klibertp 13y ago

> Does modern Racket have anything comparable to Clojure's collection primitives? See: https://news.ycombinator.com/item?id=6300845 https://news.ycombinator.com/item?id=6300845 Also, yes, there are generic "sequence" operations which you can use to abstract away a type of a collection you use. There are lazy sequences too, although they are not the default. There is also a set of very powerful "for" forms, which are an alternative to recursion when traversing sequences (and can function as sequence comprehensions, too). > and Scheme emphasizes simplicity of implementation. But it still bums me out. There is a reason why Racket name was changed from PLT Scheme. Racket outgrow Scheme some time ago and continues to grow still. It is "Scheme with batteries included", which means it's not Scheme anymore. But it makes it a great language for practical applications. It's not that great for embedding, though, while normal Schemes are. Anyway, I find Racket to be the most impressive language I've seen until now. It could use some more developers working on it, but that's all it needs to become on par with Clojure - or any other language for that matter. This makes it's design truly impressive, in my opinion at least.