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

A difference between Haskell and Common Lisp

chrisdone.com

Post reply on HN
Print view View original

11–20 of 203 posts

Re: A difference between Haskell and Common Lisp

#11

Post by galfarragem »

fnordsensei wrote: post #3

Is this really a philosophical difference? Granted, I've only used Clojure as far as Lisps go, but composability seems to be something that's emphasized. Rather than (remove-if-not #'p xs :count 5 :start 3) It seems to me like most Clojure users would do something like (->> xs (drop 3) (filter p) (take 5)) which is much closer to take 5 . filter p . drop 3

My first contact with programming (besides BASIC) was (auto)lisp. It was kind of a first love: every language I tried after Lisp was a disappointment. Then I found Haskell..

Re: A difference between Haskell and Common Lisp

#13

Post by kiiski »

PuercoPop wrote: post #9

Minor nitpick. The loop at the end could make the range by 'for i from 1 upto 4' instead of a list literal to more similar to the haskell code.

That wouldn't be the same. The point was filtering a list (which could contain anything, not just a sequence from 1 to 4).

The example seems a bit strange to me. Why does it have the check for i being less than 5, when the problem is "get all elements _greater_ than 5, then just the even ones of that set.". Was it supposed to be "remove all elements greater than 5..."? (edit: although the code would then only work for sorted lists; I think it'd be better to just loop over the whole list and have "(and (< i 5) (evenp i))" as the condition for collecting)

Re: A difference between Haskell and Common Lisp

#14

Post by vorg »

Haskell has strong typing and lazy evaluation, which makes it easy for functions to take only one argument at a time. Although a function could take a tuple parameter, it's usually rewritten to take each component of the tuple as a separate parameter, which makes the strong typing and built-in currying simple, higher structures like monads possible, and a syntax to suit this style. Lisp functions and macros OTOH must be variadic to enable the homoiconicity of the language. It's therefore much more difficult for parameters to be typed, or to curry them.

These two styles make Haskell and Lisp mutually incompatible, unless they use clunky addons like Template Haskell macros or Typed Clojure annotations. The pure form of each language, however, is based on two mutually exclusive foundations, i.e. strongly typed auto-curried parameters vs variadic untyped macro parameters. The poster child of each language, i.e. monads and macros, thus also don't mix well with each other.

Re: A difference between Haskell and Common Lisp

#15

Post by fnordsensei »

catnaroek wrote: post #10
fnordsensei wrote: post #3

Is this really a philosophical difference? Granted, I've only used Clojure as far as Lisps go, but composability seems to be something that's emphasized. Rather than (remove-if-not #'p xs :count 5 :start 3) It seems to me like most Clojure users would do something like (->> xs (drop 3) (filter p) (take 5)) which is much closer to take 5 . filter p . drop 3

Minor nitpick. Technically, this: #(->> % (drop 3) (filter p) (take 5)) Is equivalent to: take 5 . filter p . drop 3

Is

    take 5 . filter p . drop 3
An anonymous function call in Haskell? I don't know the language (although it's on my to-learn sequence).

Re: A difference between Haskell and Common Lisp

#16

Post by [deleted] »

catnaroek wrote: post #10
fnordsensei wrote: post #3

Is this really a philosophical difference? Granted, I've only used Clojure as far as Lisps go, but composability seems to be something that's emphasized. Rather than (remove-if-not #'p xs :count 5 :start 3) It seems to me like most Clojure users would do something like (->> xs (drop 3) (filter p) (take 5)) which is much closer to take 5 . filter p . drop 3

Minor nitpick. Technically, this: #(->> % (drop 3) (filter p) (take 5)) Is equivalent to: take 5 . filter p . drop 3

[deleted]

Re: A difference between Haskell and Common Lisp

#18

Post by catnaroek »

fnordsensei wrote: post #15
catnaroek wrote: post #10

Earlier quoted context omitted.

Minor nitpick. Technically, this: #(->> % (drop 3) (filter p) (take 5)) Is equivalent to: take 5 . filter p . drop 3

Is take 5 . filter p . drop 3 An anonymous function call in Haskell? I don't know the language (although it's on my to-learn sequence).

It's an anonymous function, which it not being called.

Re: A difference between Haskell and Common Lisp

#20

Post by agumonkey »

fnordsensei wrote: post #3

Is this really a philosophical difference? Granted, I've only used Clojure as far as Lisps go, but composability seems to be something that's emphasized. Rather than (remove-if-not #'p xs :count 5 :start 3) It seems to me like most Clojure users would do something like (->> xs (drop 3) (filter p) (take 5)) which is much closer to take 5 . filter p . drop 3

Funny how when I think about Lisp I think about that kind of code, while other people see elisp imperative, autolisp and common-lisp full-featured system.
Post reply on HN