I hope you like this one, as it is my ever-first attempt at a golf.

The challenge is to create a 2D-array that contains indici of all sectors in a multi-dimensional space. The indici are given as unitary vectors in that space.

Eg., in a flat plane (2D), there are four sectors, so we have 4 vectors: 

  -1   -1
  -1    1
   1   -1
   1    1

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that point each to a quadrant: 
          |
 (-1, 1)  |  ( 1, 1)
          |
 -------------------
          |
 (-1,-1)  |  ( 1,-1)
          |

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This of course comes handy when you want mirror some image or curve.

The constraints are: (i) strict compliant, (ii) return a reference to an 2D-array and (iii) only the code inside the sub is counted (believe the last is standard, isn't it?). Furthermore: the vectors must be unitary vectors in the inner dimension. The function takes as input a scalar holding the number of dimensions disired.

Here is a starting point at 79 chars: 

sub iterate_dim{
[map[map$_*2-1,split"",$_],map{substr unpack("B*",chr$_-1),-$_[0]}1..2
+**$_[0]]
}

#and call it:
my $AoA = iterate_dim( 2 );

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Have fun,

Jeroen
"We are not alone"(FZ)

Replies are listed 'Best First'.
Re (tilly) 1: Golf: Indici to all sectors of an xD space
by tilly (Archbishop) on Oct 10, 2001 at 21:55 UTC
    46 characters. 
    sub h {
@;=[];@;=map{[@$_,1],[@$_,-1]}@;for 1..pop;\@;
}

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    Note that strict compliance bought absolutely no safety here, I just got around it with using a global punctuation variable. But I would have used a global punctuation variable anyways, it allows me to save a space in front of the for. Therefore I consider strict compliance in golf to be a useless constraint. It is too easily satisfied in point while disregarded in spirit.
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[d/l]
      I can't beat this, but here's strict in spirit at 46:
        
      sub h {
$_[0]?[map{[@$_,1],[@$_,-1]}@{h(-1+pop)}]:[[]]
}

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         MeowChow                                   
               s aamecha.s a..a\u$&owag.print
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[d/l]
        OK, strict in spirit at 44. 
        sub h{
#23456789_123456789_123456789_123456789_1234
eval'['.('map{[@$_,1],[@$_,-1]}'x pop).'[]]'
}

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        UPDATE
        Well strict and warnings compliant in 43: 
        sub h{
#23456789_123456789_123456789_123456789_123
[eval(('map{[@$_,1],[@$_,-1]}'x pop).'[]')]
}

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        and then strict alone in 39: 
        sub h{
#23456789_123456789_123456789_123456789
[eval'map{[@$_,1],[@$_,-1]}'x pop.'[]']
}

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        UPDATE 2
        Warnings as well in 40: 
        sub h{
#23456789_123456789_123456789_123456789_
[eval'map{[@$_,1],[@$_,-1]}'x$_[0].'[]']
}

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Re: Golf: Indici to all sectors of an xD space
by trantor (Chaplain) on Oct 11, 2001 at 02:47 UTC

    35 characters, both warnings and strict compliant: 

    #        1         2         3
#2345678901234567890123456789012345
[map{eval"[$_],"}glob'{-,}1,'x pop]

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    I used the approach discussed in Web-Safe Color Chart

    -- TMTOWTDI

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[d/l]
      Really cute. Unportable under 5.005, but portable on 5.6. However one technical note, you can reduce it to 29: 
      sub h {
#        1         2
#2345678901234567890123456789
[map[eval],glob'{-,}1,'x pop]
}

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[reply]
[d/l]
      Nice... since I've had a hand passing that glob trick around perhaps I should attempt to shave a few chars off this tricky entry....

      30 chars... passes warnings and strict: (though not necessarily taint compliant) 

      #        1         2         3
#23456789012345678901234567890
[map{[eval]}glob'{-,}1,'x pop]

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      Doh! tilly was quicker, and beat me by a char (of course, I originally learned the glob trick from him, so perhaps thats how it should be...)

      -Blake

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