my @header_line = ('id', 'name', 'age');
my %fields;
@fields{@header_line} = (0 .. $#header_line);
#result: %fields = { id => 0, name => 1, age => 2};

##</code><code>##

#!/usr/bin/env perl
use strict;
use warnings;
use Algorithm::Permute;

my @people = qw(Brian Carlos Dana Evan Farra);
my $iter = new Algorithm::Permute(\@people);
while (my @perm = $iter->next) {
 my %positions;
 @positions{@perm} = (0..$#perm);
 my $test =
   #Brian next to Dana
   abs($positions{Brian} - $positions{Dana}) == 1
   #Dana not next to Evan
   && abs($positions{Dana} - $positions{Evan}) > 1
   #Carlos on Dana's right
   && $positions{Carlos} - $positions{Dana} == 1
   #one seat between Brian and Farra
   && abs($positions{Brian} - $positions{Farra}) == 2;
 if ($test) {
   print "@perm\n";
 }
}