Comments on: Logo, Ruby & JavaScript

By: XXX

XXX — Tue, 11 Nov 2008 02:04:32 +0000

APL:

?,??.{?,' ',?}/('small' 'medium' 'large')('vanilla' 'ultra chocolate' 'lychee' 'rum raisin' 'ginger')('cone' 'cup')

J (2 solutions):

>,{ ('small';'medium';'large');('vanilla';'ultra chocolate';'lychee';'rum raisin';'ginger'); , { options

By: Ric

Ric — Tue, 11 Nov 2008 01:13:01 +0000

There are some APL, J & K versions of this program in this comp.lang.apl thread. Here is a version in J:

   Options=: ;: each ('small large medium');('ginger lychee rum_raisin ultra_choc vanilla');('cone cup')
   choices=: monad : ';:^:_1 >,{ y'
   choices Options
small vanilla cone
small vanilla cup
small ultra_choc cone
...
large rum_raisin cup
large ginger cone
large ginger cup

By: Neil

Neil — Sat, 02 Feb 2008 18:22:15 +0000

One more:


choices xss = mapM_ (putStrLn . unwords) (sequence xss)

main = choices [["small", "medium", "large"],
 ["vanilla", "ultra chocolate", "lychee", "rum raisin", "ginger"],
 ["cone", "cup"]]

By: Neil

Neil — Sat, 02 Feb 2008 17:29:34 +0000

Having just usefully taught myself how to use ampersands etc. in order to prevent “<-” being parsed as a comment, I can finally unveil my Haskell version.

Thanks for your patience. (And fingers crossed for third attempt…)

Ben’s Haskell version is shorter, of course, but I think mine might be more ‘idiomatic’ in that it abides by old Haskell maxim: ‘use monads whenever you see the slightest opportunity to show off the fact that you know how they work’.


choices :: [[String]] -> IO ()
choices xss = mapM_ (putStrLn . unwords) (f xss)
    where f [] = return []
          f (zs:zss) = do x <- zs
                          xs <- f zss
                          return $ x:xs

main = choices [["small", "medium", "large"], ["vanilla", "ultra chocolate", "lychee", "rum raisin", "ginger"], ["cone", "cup"]]

By: Neil

Neil — Sat, 02 Feb 2008 17:04:42 +0000

I hardly ever use HTML, so unsurprisingly I screwed up my first attempt to post a comment. Sorry (again)!


choices :: [[String]] -> IO ()
choices xss = mapM_ (putStrLn . unwords) (f xss)
    where f [] = return []
          f (zs:zss) = do x

By: Neil

Neil — Sat, 02 Feb 2008 17:01:28 +0000

Sorry - couldn’t help writing another Haskell version:

choices :: [[String]] -> IO () choices xss = mapM_ (putStrLn . unwords) (f xss) where f [] = return [] f (zs:zss) = do x

By: Brian Adkins

Brian Adkins — Thu, 31 Jan 2008 22:41:32 +0000

After helpful feedback on the Arc forum and discovering join:

(def choices (menu (o result '()))
  (if menu
    (each x (car menu)
      (choices (cdr menu) (join result (list x))))
    (prall result "\n" " ")))

(choices '(
  ("small" "medium" "large")
  ("vanilla" "ultra chocolate" "lychee" "rum raisin" "ginger")
  ("cone" "cup")))

By: Brian Adkins

Brian Adkins — Thu, 31 Jan 2008 16:28:57 +0000

I thought I’d put a first draft up of a version in Arc

(def joinstr (lst (o sep " "))
  (if lst
    (string (car lst) (apply string (map [string sep _] (cdr lst))))
    ""))

(def choices (menu (o result '()))
  (if menu
    (each x (car menu)
      (choices (cdr menu) (cons x result)))
    (prn (joinstr:rev result))))

(choices (list
  (list "small" "medium" "large")
  (list "vanilla" "ultra chocolate" "lychee" "rum raisin" "ginger")
  (list "cone" "cup")))

By: lojic.com » Blog Archive » Learning Logo - Part One

lojic.com » Blog Archive » Learning Logo - Part One — Sat, 05 Jan 2008 21:37:06 +0000

[...] August, I wrote a blog post comparing a short function (from Brian Harvey’s home page) in Logo and several other [...]

By: PL

PL — Sun, 30 Sep 2007 15:18:33 +0000

Clean:

items =: [["small","medium","large"],["vanilla","chocolate"],["cup","cone"]]
menu i
| i == [] = “”
= hd i +++ “\n” +++ menu (tl i)
Start = menu [x+++” “+++y+++” “+++z \\ x