Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

A Haskell Programmer Tries to Learn Racket

artyom.me

Post reply on HN
Print view View original

61–70 of 163 posts

Re: A Haskell Programmer Tries to Learn Racket

#61

Post by nnq »

This sums up quite a lot about Lisps in general. I'm amazed OP got so fast to this "insight" :)

    (And this is probably Lisp's greatest weakness as well – with this level of
    possible diversity, everyone has to use the “common lowest denominator”
    simply because nobody can agree on what alternative syntax / library / etc.
    is better and should be used.)

    Off-topic: it's not enough to give everyone opportunity to improve the
    language; you have to choose the winners and promote them heavily. The rules
    of free market don't work here; people won't use the best thing, they'll use
    the one which is available out of the box and which is used by their peers.

Re: A Haskell Programmer Tries to Learn Racket

#63

Post by MichaelGG »

ludwigvan wrote: post #32
MichaelGG wrote: post #11

Earlier quoted context omitted.

I keep flipping back and forth, thinking I don't get it, then thinking others don't get it. Single-threaded JS with callbacks. OK? What am I missing? The only thing Node has going for it is a lot of networking libraries. It's not fast, the async style leads to callback hell, JS is a terrible language, and their package management system is slow and bloated (or at least the packages are)[1]. Yet people think it's some…

Straight from the horse's mouth: "Node is popular because it allows normal people to do high concurrency servers. It's not the fastest or leanest or even very well put together - but it makes good trade offs in terms of cognitive overhead, simplicity of implementation, and performance. I have a lot of problems with Node myself - but the single event loop per process is not one of them. I think that is a good programm…

If you don't want shared memory... then don't use it. Other languages are not stopping you from copying objects and using a message passing system.

And it seems rich to complain about syntax when the language of choice has "function" as it's lambda operator.

Re: A Haskell Programmer Tries to Learn Racket

#64

Post by swift »

dllthomas wrote: post #50
rdtsc wrote: post #35

Earlier quoted context omitted.

> The future of server programming does not have parallel access to shared memory. Yeah but it could be IO parallelism. There could be two instances of callback chains of sequence C1->C2->C3 started such that the the second starts before the first one finished. As in C1->C2 ran then C1 gets called again. If in those callbacks you update a data structure (a database record?), you now accessed that data in parallel. So…

There's some need to synchronize, but hot damn is it simpler when you're dealing with sensible blocks of high-level statements than when you're dealing with out-of-order parts of assembly instructions.

That's true, but personally I still don't find this model ideal because the synchronization points are implicit. The cleanest concept I know of for dealing with synchronization is transactions.

Re: A Haskell Programmer Tries to Learn Racket

#65

Post by vitalique »

laichzeit0 wrote: post #58
comex wrote: post #10

One note: > Racket's default IDE is better than GHCi and probably on par with Emacs (you almost certainly can configure Emacs to be better than anything, but it's not trivial and people don't bother, while DrRacket provides autocompletion and documentation out of the box). Last I used it (a few years ago), DrRacket was very laggy, so I would find it very hard to use for a serious project. YMMV, maybe it's improved.

Try the Geiser plugin for Emacs. It allows you to connect to the Racket REPL (either it starts a new instance of Racket, or it can connect to a socket/port). I'm a Vim user and went through elaborate pains to get Emacs working almost like Vim just so I could go through SICP this way.

Could you please outline your final setup besides using Geiser? I also come from Vim-land, have almost zero experience with Emacs and already understood that, to learn SICP, setting up and learning Emacs is going to be easier than setting up Vim for the task.

Re: A Haskell Programmer Tries to Learn Racket

#66

Post by jamii »

ANTSANTS wrote: post #51
Sean-Der wrote: post #45

Earlier quoted context omitted.

I come from a background using Common Lisp for system and web development so I may see things differently than people who were introduced to it academically. Your code looks great, mine just needed to compile :) The cons pair is a a really powerful primitive data structure, it is the linked list of Lisp. You can build a lot of powerful structures given this great base. I really don't it matters what architecture your…

I mean, it's neat that you can build everything out of cons, in the sense that it's neat that Turing machines and the lambda calculus can perform any computation, but that doesn't mean it's a good idea to so in your code, any more than encoding numbers with Church numerals. Why use alists when you can use hash tables, why use... weird SICP-style struct list things when you could just use structs/vectors, etc. >Hash T…

> I wonder what Clojure programmers do here.

About the same.

    (defn message [text & {:keys [style color]}]
      ...)

    (message "Text" :style :bold :color :red)
Because typing those extra two brackets is apparently too much trouble.

Re: A Haskell Programmer Tries to Learn Racket

#67

Post by ANTSANTS »

jamii wrote: post #66
ANTSANTS wrote: post #51

Earlier quoted context omitted.

I mean, it's neat that you can build everything out of cons, in the sense that it's neat that Turing machines and the lambda calculus can perform any computation, but that doesn't mean it's a good idea to so in your code, any more than encoding numbers with Church numerals. Why use alists when you can use hash tables, why use... weird SICP-style struct list things when you could just use structs/vectors, etc. >Hash T…

> I wonder what Clojure programmers do here. About the same. (defn message [text & {:keys [style color]}] ...) (message "Text" :style :bold :color :red) Because typing those extra two brackets is apparently too much trouble.

I can't say I expected it to look like that.

Re: A Haskell Programmer Tries to Learn Racket

#68

Post by JimmyM »

nly wrote: post #17
MichaelGG wrote: post #11

Earlier quoted context omitted.

I keep flipping back and forth, thinking I don't get it, then thinking others don't get it. Single-threaded JS with callbacks. OK? What am I missing? The only thing Node has going for it is a lot of networking libraries. It's not fast, the async style leads to callback hell, JS is a terrible language, and their package management system is slow and bloated (or at least the packages are)[1]. Yet people think it's some…

My theories: 1. Using the same programming language on both sides of HTTP often appeals to a developers visceral sense of elegance, or tidiness, even though it this alone inherently solves no existing problems. 2. It's powered by Googles V8 engine, which means people already associate it with this "super fast JIT" thing that lives in their favourite browser. It must be efficient, right? 3. The crowned alternative is…

PHP best practices might be becoming like Java, but the language is far, far, far from anything close as far as I can see.

Again, as far as I can see it's as simple to hack together a script in PHP as it ever was. What's changing about the language that makes it more like Java?[1]

1. I tried and failed to make this sentence seem as non-passive-aggressive as possible. I'm genuinely interested, as it's not something I've come across and I'm by no means a PHP expert.

Re: A Haskell Programmer Tries to Learn Racket

#69

Post by arethuza »

ANTSANTS wrote: post #51
Sean-Der wrote: post #45

Earlier quoted context omitted.

I come from a background using Common Lisp for system and web development so I may see things differently than people who were introduced to it academically. Your code looks great, mine just needed to compile :) The cons pair is a a really powerful primitive data structure, it is the linked list of Lisp. You can build a lot of powerful structures given this great base. I really don't it matters what architecture your…

I mean, it's neat that you can build everything out of cons, in the sense that it's neat that Turing machines and the lambda calculus can perform any computation, but that doesn't mean it's a good idea to so in your code, any more than encoding numbers with Church numerals. Why use alists when you can use hash tables, why use... weird SICP-style struct list things when you could just use structs/vectors, etc. >Hash T…

In Common Lisp you can create your own syntax for hash table literals fairly easily with a reader macro:

http://frank.kank.net/essays/hash.html

Mind you - reader macros should be used with a degree of care otherwise you basically create completely new language. I remember working on a project where I got a drop of some code from one of the other organizations in the project (by tape, this was a long time ago) opening the file and wondering what language the code was written in and taking a while to realize that it was indeed Lisp - but one that had used reader macros to do strange and terrible things.

Mind you, once I learned about reader macros I went on to do my own crazy stuff with them - they are almost too powerful a feature (almost!).

Post reply on HN