I can create filehandles to strings in Perl 5, how do I do it in Perl 6?

Question

In Perl 5, I can create a filehandle to a string and read or write from the string as if it were a file. This is great for working with tests or templates.

For examp

Answer 1

Reading

The idiomatic way to read line-by-line is the .lines method, which is available on both Str and IO::Handle.

It returns a lazy list which you can pass on to for, as in

my $text = "A\nB\nC\n";

for $text.lines -> $line {
     # do something with $line
}

Writing

my $scalar;
my $fh = IO::Handle.new but
         role {
             method print (*@stuff) { $scalar ~= @stuff };
             method print-nl        { $scalar ~= "\n" }
         };

$fh.say("OH HAI");
$fh.say("bai bai");

say $scalar
# OH HAI
# bai bai

(Adapted from #perl6, thanks to Carl Mäsak.)

More advanced cases

If you need a more sophisticated mechanism to fake file handles, there's IO::Capture::Simple and IO::String in the ecosystem.

For example:

use IO::Capture::Simple;
my $result;
capture_stdout_on($result);
say "Howdy there!";
say "Hai!";
capture_stdout_off();
say "Captured string:\n" ~$result;