The typical approach in Perl would be a while loop...

my $it = tqdm(100);
while (my $i = $it->next) {
    ...
}

[download]

Plenty of variations are possible, for example, $it doesn't need to be an object, it could just be a code ref; or, if it is an object, it can overload the <> operator (while(<$it>)), etc.

BTW, Higher-Order Perl is great for this kind of stuff.

Update: One advantage of overloading <> is that a while(<$it>) is automatically translated to while (defined($_ = readline $it)), meaning that only undef terminates the sequence, and not other false values like 0:

use warnings;
use strict;

{
    package Iterator;
    use overload '<>' => sub {
        my $self = shift;
        if (wantarray) {
            my @all;
            while (defined( my $x = $self->() ))
                { push @all, $x }
            return @all;
        }
        else { return $self->() }
    };
    sub new {
        my $class = shift;
        my @values = @_;
        my $i=0;
        return bless sub {
            if ($i>=@values) { $i=0; return }
            return $values[$i++];
        }, $class;
    }
}

use Test::More tests=>2;

my $it1 = Iterator->new(-5..5);
my @o1;
while (<$it1>) {
    push @o1, $_;
}
is_deeply \@o1, [-5,-4,-3,-2,-1,0,1,2,3,4,5];

SKIP: {
    skip "need Perl >= v5.18 for overloaded <> in list context",
        1 unless $] ge '5.018'; # [perl #47119]
    my $it2 = Iterator->new(-5..5);
    is_deeply [<$it2>], [-5,-4,-3,-2,-1,0,1,2,3,4,5];
}

[download]

In reply to Re: Porting tqdm to Perl (updated) by haukex
in thread Porting tqdm to Perl by perlancar

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