Consider a slice @A[3,4,5,6,7]. That could be written @A[3..7] instead, and if you consider @A[3..50] that's a good thing.

Well, what about @A[7,6,5,4,3]? How would you write @A[50..3] to actually work?

I think that @A[reverse 3..50] should be sufficient, and that Perl6 will have support for open-ended lists so more exoitic generators can be created that don't force creation of the entire list ahead of time.

Replies are listed 'Best First'.
Re: .. in reverse
by mojotoad (Monsignor) on Aug 30, 2002 at 23:17 UTC
    ttaM

    .scitehtsea naht rehto eussi na fo hcum s'ti kniht t'nod I ?)syarra ton( stsil fo slasrever ezimitpo relipmoc lrep eht t'nseoD

    Doesn't the perl compiler optimize reversals of lists (not arrays)? I don't think it's much of an issue other than aesthetics.

    Matt

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Re: .. in reverse
by BrowserUk (Patriarch) on Aug 31, 2002 at 00:53 UTC
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[d/l]
[select]
      Of course they aren't always interchangable.... One can be used as an lvalue the other can't. 
      #!/usr/bin/perl -wT
use strict;

my @a             = 'a'..'f';
@a[reverse 5..10] = 'A'..'F';  # can you rewrite this line?

print "@a\n";

__END__

a b c d e F E D C B A

      [download]

      -Blake

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[d/l]

        Yes! But It's not as pretty. 

        #!/usr/bin/perl -w
use strict;

my @a       = 'a'..'f';
#@a[reverse 5..10] = 'A'..'F';  # can you rewrite this line?
splice @a, 5, 10-5, reverse ('A'..'F');

print "@a\n";
__END__
C:\test>194289.pl
a b c d e F E D C B A

        [download]
        Well It's better than the Abottoire, but Yorkshire!
[reply]
[d/l]
        @a[reverse 5..10] = 'A'..'F';  # can you rewrite this line?
        @a[5..10] = reverse 'A'..'F';

        Not that it really addresses the point...

        -sauoq
"My two cents aren't worth a dime.";
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[d/l]
[select]

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