Berik Visschers

NAME

Acme::Hyperindex - Look deep into structures using a list of indexes

SYNOPSIS

  use strict;
  use Acme::Hyperindex;

  my @struct = (
      { j_psi => [qw( eta_prime phi kaon )] },
      { j_psi => [qw( selectron down tau_sneutrino )] },
      { j_psi => [qw( upsilon gluino photino )] }
  );

  print @struct[[ 2, 'j_psi', 1 ]], "\n"; ### Prints gluino
  my $row = @struct[[ 1, 'j_psi' ]];      ### Row contains [qw( selectron down tau_sneutrino )]

DESCRIPTION

When you use dynamic datastructures, the perl index syntax may not be felxible enough. A little examle:

  my @struct = (
      {
          pion        => [
              [qw(strange j_psi positron)],
              [qw(down_squark electron gluino)],
          ],
          w_plus_wino => [
              [qw(neutralino tau kaon)],
              [qw(charm_squark photino strange_squark)]
          ],
      },
  );

Now to get to the kaon particle, normally we use:

  my $particle = $struct[0]->{w_plus_wino}->[2];
   -- or better --
  my $particle = $struct[0]{w_plus_wino}[2];

But what if you don't know how deep your datastructure is at compile time? 'Course this is doable:

  my $particle = \@struct;
  $particle = $particle->[$_] for qw(0 pion 2);

Two problems here: Perl will tell you 'Not an ARRAY reference' once we try to index in the hash on 'pion' with this array indexing syntax. It's damn ugly and looks complicated.

So Acme::Hyperindex lets you index arbitrary deep into data structures:

  my $particle = @struct[[ 0, 'pion', 2 ]];
    -- or even --
  my $particle = @struct[[ @indexes ]];
    -- or --
  my $particle = @struct[[ get_index() ]];
    -- or --
  my $particle = @struct[[ $particleindexes[[ 3, 42 ]] ]];

Acme::Hyperindex now also lets you index on scalars, arrays and hashes:

  $struct[[ ... ]];
  @struct[[ ... ]];
  %struct[[ ... ]];

And lists ary auto-derefed in list context:

  my $struct = [ [qw(a b c)], [qw(d e f)] ];

  my $foo = $struct[[ 0 ]]; # $foo contains a ref to qw(a b c)
  my @foo = $struct[[ 0 ]]; # @foo contains qw(a b c)

BUGS

Perl code is hard to parse, and there are surely situations where my parsing fails to do the right thing.

TODO

  • make the sourcefilter optionally

  • Scalar references within the datasructure..

      my $struct = [ \[qw(a b c)] ];

    There should be some way to get to 'a'

  • Generate nonexisting references optionally

    When you try to index deeper than the data structure is:

      my $struct = [];
      $struct[[ 0, 'foo', 42 ]];

AUTHOR

Berik Visschers <berikv@xs4all.nl>

COPYRIGHT

Copyright 2005 by Berik Visschers <berikv@xs4all.nl>.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

See http://www.perl.com/perl/misc/Artistic.html