CODEWITHSUNDEEP
perlvariableshash
jordon vj
jordon vj

Reputation: 13

Making Perl's "specific declarations" as variable

I was looking for some sort of solution if the following setup can be interpreted as formal declaration of the variables , if possible. What i have is :

my $str_1 = "{cow}" ;

my $str_2 = "{cow}{black}{tasty_milk}";

what i want is :

(Based on above variable string is it possible to initialize a hash directly, something like :)

my %hash=();

$hash."*some operator* on $str_i"  = 'Initialized' ;

This "some operator" should make $hash to recognize as hash as it was declared earlier. i.e Input specific hash initialization.

PS: I don't want to write a function that will work on the string and get all information to initialize the hash.

Upvotes: 1

Views: 103

Answers (2)

ikegami
ikegami

Reputation: 386351

Say you had the following input instead:

my @path = qw( cow black tasty_milk );

Then you can use the following:

use Data::Diver qw( DiveVal );

DiveVal(\%hash, map \$_, @path) = 'value';

So, with Data::Diver, we get:

use Data::Diver qw( DiveVal );

$str =~ /^(?:\{\w+\})+\z/
   or die("Unrecognized format");

my @path = $str =~ /(\w+)/g;
DiveVal(\%hash, map \$_, @path) = 'value';

Without a module:

sub dive_val :lvalue { my $p = \shift;  $p = \( $$p->{$_} ) for @_;  $$p }

$str =~ /^(?:\{\w+\})+\z/
   or die("Unrecognized format");

my @path = $str =~ /(\w+)/g;
dive_val(\%hash, @path) = 'value';

Upvotes: 4

mkHun
mkHun

Reputation: 5927

Try the following with anonymous hash

use Data::Dumper;
use warnings; 
use strict;

my $str_2 = "{cow}{black}{tasty_milk}";
my %hash;
my $ref =\%hash;
my $val;
my $lp = () = $str_2=~m/\}/g; #count the number of }
my $i = 1;
while($str_2=~m/\{(\w+)\}/g)
{
    $val = $1;

    last if ($lp == $i); 

    $ref->{$val} = {}; #make the anonymous hash        

    $ref = $ref->{$val};   #add the data into anonymous hash

    $i++;

}
$ref->{$val} = "value"; #add the last value

print Dumper \%hash;

Upvotes: 0

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