#!/usr/bin/perl

use 5.018003;
use warnings;

use Cwd qw( abs_path );
use Path::Tiny;
use File::Spec;

my @pth = qw(
    /a/b/c/d/../../../e
    /a/../b/./c//d
    ../scripting
    ./tmp
    /tmp/../../../tmp
    );

sub resolves {
    my ($p, $r) = @_;
    printf "%-20s -> %s\n", $p, $r // "$p does not resolve";
    } # resolves

say "OP";
foreach my $pth (@pth) {
    my @c = reverse split m{/+}, $pth; # /+ removes empty elements
    my @c_new;
    while (@c) {
        my $component = shift @c;
        next unless length ($component);
        $component eq "." and @c and next;
        if ($component eq ".." and @c) {
            my $i = 0;
            while ($i <= $#c && $c[$i] =~ m/^\.{0,2}$/) {
                $i++;
                }
            splice @c, $i, 1;
            next;
            }
        push @c_new => $component;
        }
    @c = reverse @c_new;
    $c[0] =~ m/^\.\.?$/ or unshift @c => "";
    resolves $pth, join "/" => @c;
    }

say "Cwd::abs_path";
foreach my $pth (@pth) { resolves $pth, abs_path ($pth);                }

say "Path::Tiny::path";
foreach my $pth (@pth) { resolves $pth, Path::Tiny::path ($pth);        }

say "File::Spec::canonpath";
foreach my $pth (@pth) { resolves $pth, File::Spec->canonpath ($pth);   }