"So, we often hear complaints that J is terse to the point of being cryptic.
 That it is unreadable.  Let's see if that's true."

I guess there are a lot of readers who think this line is cryptic and
unreadable.

It would be good to explain what it is doing step by step

   load'trace'
   trace'(#~ ] -.@:e. [: , */~)@:(2 + i.) 12'
 --------------- 5 Trident ----
 2
 +
 i.
 2 + i.
 --------------- 8 Paren ------
 (
 2 + i.
 )
 2 + i.
 --------------- 3 Adverb -----
 *
 /
 */
 --------------- 3 Adverb -----
 */
 ~
 */~
 --------------- 5 Trident ----
 [:
 ,
 */~
 [: , */~
 --------------- 4 Conj -------
 -.
 @:
 e.
 -.@:e.
 --------------- 5 Trident ----
 ]
 -.@:e.
 [: , */~
 ] -.@:e. [: , */~
 --------------- 3 Adverb -----
 #
 ~
 #~
 --------------- 6 Bident -----
 #~
 ] -.@:e. [: , */~
 #~ (] -.@:e. [: , */~)
 --------------- 8 Paren ------
 (
 #~ (] -.@:e. [: , */~)
 )
 #~ (] -.@:e. [: , */~)
 --------------- 4 Conj -------
 #~ (] -.@:e. [: , */~)
 @:
 2 + i.
 (#~ (] -.@:e. [: , */~))@:(2 + i.)
 --------------- 0 Monad ------
 (#~ (] -.@:e. [: , */~))@:(2 + i.)
 12
 2 3 5 7 11 13
 ==============================
2 3 5 7 11 13


2008/4/4, Dan Bron <[EMAIL PROTECTED]>:
>
> Henry wrote:
> > Finds primes less than y.
>
>
> Ah, vindication!  If you wanted to be more precise:
>
>    it returns a vector of primes less than  y+2  (i.e.,
>    if  y+1  is prime, it is returned), sorted according
>    to the sign of y (if  y>0  implies  /:~  and  y<0
>    implies   \:~  )
>
> And there actually may be more hidden depths for weirder arguments.  Not
> sure.
>
> Is anyone interested in posting a more difficult challenge?
>
>
> -Dan
>
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>



-- 
Björn Helgason, Verkfræðingur
Fugl&Fiskur ehf,
Fornustekkum II, 781 Hornafirði
Po Box 127,801 Selfoss ,
t-póst: [EMAIL PROTECTED]
gsm: +3546985532
Landslags og skrúðgarðagerð, gröfuþjónusta
http://groups.google.com/group/J-Programming


Tæknikunnátta höndlar hið flókna, sköpunargáfa er meistari einfaldleikans

góður kennari getur stigið á tær án þess að glansinn fari af skónum
          /|_      .-----------------------------------.
         ,'  .\  /  | Með léttri lund verður        |
     ,--'    _,'   | Dagurinn í dag                     |
    /       /       | Enn betri en gærdagurinn  |
   (   -.  |        `-----------------------------------'
   |     ) |        (\_ _/)
  (`-.  '--.)       (='.'=)
   `. )----'        (")_(")
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm

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