gistfile1.txt

use v6;

role Finalizable[Callable $finalizer] {
    method finalize() {
        $finalizer();
    }
}

multi sub infix:<do>(Finalizable $finalizable, Callable $callable) {
    # XXX should call $callable in caller's context
    $callable($finalizable);
    
    # RAKUDO: LEAVE is nyi
    #LEAVE { $finalizable.finalize }
    $finalizable.finalize;
}

sub my_chdir($dir) {
    my $prev = cwd;
    chdir $dir;
    $dir does Finalizable[{ chdir $prev }];
}

sub my_open($file, *%mode) {
    my $fh = open $file, |%mode;
    $fh does Finalizable[{ $fh.close }];
}

my_chdir('~/tmp') do {
    say cwd;

    my_open('greeting.txt', :w) do -> $file {
        $file.say('hello');
    }
}

say cwd;