multi-output-sigs.txt

#!/usr/bin/env perl6

use Test;
use File::Temp;

multi sub dtext(IO::Handle:D $f, Str $str is copy, Bool :$triple = False) {
    my $s = $str ~ $str;   # double the input text
    $s ~= $str if $triple; # or triple it
    $f.say: $s;
}
multi sub dtext(Str:D $str is rw, Bool :$triple = False) {
    # internal temp file name ($f) and its handle ($fh)
    my ($f, $fh) = tempfile; # note temp file are opened rw
    my $s = $str;
    dtext($fh, $s, :$triple); # double the text

    # assign the file contents to the incoming text
    $str = slurp $f;
}

my $f   = 'test-file.txt';
my $sr  = 'text';
my $srw = $sr;
# expected output:
my $res2 = "texttext\n";
my $res3 = "texttexttext\n";

# the default double-text option
my $fh = open $f, :w;
dtext($fh, $sr);            # output to file
my $sr-out = slurp $f;
dtext($srw);                # output to string

# try the triple option
$fh = open $f, :w;
dtext($fh, $sr, :triple);   # output to file
my $sr3-out = slurp $f;
my $srw3 = $sr;
dtext($srw3, :triple);      # output to string

# test all
is $sr-out, $res2;
is $srw,    $res2;

is $sr3-out, $res3;
is $srw3,    $res3;

done-testing